700/23 vs 700/25 tires ?
jeffreybike
speed. Will 2mm make you that slower or faster?
thanks, Jeff
Chalo
>
> Is there any real difference between 23mm and 25mm tires as far as
> speed. Will 2mm make you that slower or faster?
There is no significant difference in speed between those two sizes of
tire. Too narrow a tire will slow you down quite a lot when you get a
pinch flat and have to stop and repair it.
Instrumented tests have shown that for tires of equal construction,
wider tires have slightly less rolling resistance at the same
pressure. Narrower tires have slightly less aerodynamic drag. While
these factors mostly offset each other, all other benefits (rim
protection, ride quality, wear life, pinch flat resistance, traction)
give the advantage to the wider tire.
Sport road bikes generally work best with the widest tire that will
fit under the brakes and between the chainstays with adequate
clearance. This is often a 28mm tire.
Chalo
John Forrest Tomlinson
<chalo....@gmail.com> wrote:
>Instrumented tests have shown that for tires of equal construction,
>wider tires have slightly less rolling resistance at the same
>pressure. Narrower tires have slightly less aerodynamic drag. While
>these factors mostly offset each other, all other benefits (rim
>protection, ride quality, wear life, pinch flat resistance, traction)
>give the advantage to the wider tire.
This depends on how much one weighs and what sort of roads the person
is riding on.
John Forrest Tomlinson
And also the speeds at which the person is riding.
Pete Biggs
> jeffreybike wrote:
>>
>> Is there any real difference between 23mm and 25mm tires as far as
>> speed. Will 2mm make you that slower or faster?
>
> There is no significant difference in speed between those two sizes of
> tire. Too narrow a tire will slow you down quite a lot when you get a
> pinch flat and have to stop and repair it.
The rider will never get a pinch flat if it can be inflated highly enough to
support his weight when the tyre is slammed into potholes, etc.
> Instrumented tests have shown that for tires of equal construction,
> wider tires have slightly less rolling resistance at the same
> pressure.
But wider tyres should not be inflated so highly to provide the same
suspension and traction, so then they are slower on the smoothest surfaces,
though faster on bumpy surfaces.
> Narrower tires have slightly less aerodynamic drag.
And less weight.
> While
> these factors mostly offset each other, all other benefits (rim
> protection, ride quality, wear life, pinch flat resistance, traction)
> give the advantage to the wider tire.
>
> Sport road bikes generally work best with the widest tire that will
> fit under the brakes and between the chainstays with adequate
> clearance. This is often a 28mm tire.
Often 25mm too, sometimes only 23mm.
~PB
russell...@yahoo.com
I used to use 23 mm tires exclusively. Fashion I suppose. I now use
mostly 25mm tires. I can't tell any difference in speed, comfort,
traction, flat rate, or anything else.
Peter Cole
I went through the same process, then went on to 28mm, 32mm, and now
35mm on one bike. Fatter tires might be slightly slower, but it's small
enough to not be obvious. The difference in comfort is pretty obvious.
Frank Krygowski
The first thing to realize is that tire sizes are nominal, not
actual. For many, many years tire manufacturers have mislabeled their
tires.
Why? Because many cyclists think any tiny difference will make
tremendous changes in their riding - especially differences in
weight. So Company X makes a 23 mm tire, but labels it a 25 mm tire.
And the deluded consumer looks in the catalog and says "Wow, Company X
makes a 25 that's fifteen whole grams lighter than that of Company
Y!" He buys it under false pretenses.
One of my riding buddies has always been very evenly matched with me.
In the past ten years, he's gradually gone to carbon fiber everything,
and his tires are now down to 19 mm that he says he inflates to 160
psi, to avoid pinch flats. I'm still on the same touring bike, riding
(actual measurement) 26 mm tires. He's still evenly matched with me.
It takes a big change in weight or rolling resistance to be
detectable.
Keep in mind, tires not only support your weight and give traction,
but they also provide suspension. Narrower tires are more like solid
rubber tires. A thin coating of solid rubber would have the lowest
rolling resistance on a perfectly smooth surface, but only track
racing takes place on perfectly smooth surfaces. On our roads, my
friends 19s are probably slower than my 26s.
- Frank Krygowski
landotter
I like 28-32s for road riding, whether I'm on my fixed gear or my
racked up bike. Being able to run 80psi up front makes a whole world
of comfort open up. I weigh about 170 at 6'1", another factor to
consider, and I can't understand why anyone heavier would want to ride
a 23 except for two reasons: they came with the bike, or perhaps
caught a great sale on some Vredesteins and couldn't pass em up. ;-)
To be more accurate--I like tires that weigh around 350g. With
Panaracers--that's nice puffy 32mm that rolls super fast due to the
flexible carcass. I've ridden 35-38s that are a hundred grams more--
and I do feel a bit slower. There are also terrible skinnier tires
that have a lot of rolling resistance. Worst are the "armored up"
tires that feel like garden hoses and need four tire levers to
install. They can be wide and fairly low pressure--yet still ride
terrible.
At any rate, to the OP: ride 25s for crying out loud. If you weigh
more than I do and can fit 28s, go for it. If you're not racing, the
durability and longevity is worth the tiny tradeoff in psychological
benefit that one gets by mounting ridiculously narrow tires. ;-)
Clive George
news:ff50ad56-d42d-4c7d...@m22g2000vbp.googlegroups.com...
>I used to use 23 mm tires exclusively. Fashion I suppose. I now use
>mostly 25mm tires. I can't tell any difference in speed, comfort,
>traction, flat rate, or anything else.
Didn't tyre sizes become more realistic recently? So yesterday's 23 is
today's 25, or something like that?
John Forrest Tomlinson
<land...@gmail.com> wrote:
> I can't understand why anyone heavier would want to ride
>a 23 except for two reasons: they came with the bike, or perhaps
>caught a great sale on some Vredesteins and couldn't pass em up. ;-)
This guy weighs over 180s and is using 23s in the picture. He wants
to go fast and they work well for that in races.
http://www.cyclingnews.com/photos.php?id=/photos/2006/jun06/harlem06/andyshen226
landotter
wrote:
> On Thu, 29 Jan 2009 08:21:29 -0800 (PST), landotter
>
> > I can't understand why anyone heavier would want to ride
> >a 23 except for two reasons: they came with the bike, or perhaps
> >caught a great sale on some Vredesteins and couldn't pass em up. ;-)
>
> This guy weighs over 180s and is using 23s in the picture. He wants
> to go fast and they work well for that in races.
>
Where's the evidence that he couldn't roll faster on 25s? It probably
wouldn't make a difference, ultimately. For folks that aren't racing,
you get a little more durability and comfort at the expense of
nothing.
90% of folks flatted out on the local greenway are riding 23s. There's
zero glass there, so I guess it's just fashionable to pinch flat!
gnu / linux
I use a 23 on the front, 25 on the back of my trek 2300
russell...@yahoo.com
> <russellseat...@yahoo.com> wrote in message
I think just opposite. Labeled 25 but really only 23 wide. And
labeled 23 but just 21 wide. My Vittoria Open Pro Evo CX something or
other tires are available in 23 and 25 labeled widths from the
manufacturer. I'm using the 25 labeled model. How wide they really
are, don't know. They do look wider than a 23 labeled model I have on
another bike in front. Different brand tire though. Some day I might
try a 28 labeled tire. I think they will fit on some of my road
bikes. But I have lots of 25 labeled tires to wear out first before
wasting money on more bike tires.
John Forrest Tomlinson
<land...@gmail.com> wrote:
>On Jan 29, 10:47 am, John Forrest Tomlinson <usenetrem...@jt10000.com>
>wrote:
>> On Thu, 29 Jan 2009 08:21:29 -0800 (PST), landotter
>>
>> <landot...@gmail.com> wrote:
>> > I can't understand why anyone heavier would want to ride
>> >a 23 except for two reasons: they came with the bike, or perhaps
>> >caught a great sale on some Vredesteins and couldn't pass em up. ;-)
>>
>> This guy weighs over 180s and is using 23s in the picture. He wants
>> to go fast and they work well for that in races.
>>
>> http://www.cyclingnews.com/photos.php?id=/photos/2006/jun06/harlem06/...
>
>Where's the evidence that he couldn't roll faster on 25s?
Your question was you cant' understand why anyone would make a choice
other than your, not for evidence.
That said, I have seen evidence, which I'll be too lazy to find now,
that tires the same width as the have less wind resistance than tires
that are wider.
Do you accept that? If not, I'll try to find more info.
>It probably
>wouldn't make a difference, ultimately
> For folks that aren't racing,
>you get a little more durability and comfort at the expense of
>nothing.
Ohhhh, so when you said you don't understand why anyone heavier would
want to ride a 23 you meant you don't understand why anyone heavier
doing the sort of riding *you* do would want to ride a 23. Is that
it?
John Forrest Tomlinson
<land...@gmail.com> wrote:
>90% of folks flatted out on the local greenway are riding 23s. There's
>zero glass there, so I guess it's just fashionable to pinch flat!
So let me get this straight, if I weigh 155 pounds and ride 28s I can
mock you for your tire choice and say how you seem to love risking
pinch flats, since I'm on fatter tires? And if someone the same
weight was on 35s and saw me, he could mock me?
Is that the way it works? Rather than just saying there are
tradeoffs, we can also say the person riding tires smaller than us is
making a mistake and as long as we're on larger tires than they are,
we've made the smarter choice?
OK I understand now.
Chalo
>
> John Forrest Tomlinson wrote:
> >
> >Chalo wrote:
> >>
> >>Instrumented tests have shown that for tires of
> >>equal construction, wider tires have slightly less
> >>rolling resistance at the same pressure. Narrower
> >>tires have slightly less aerodynamic drag. While
> >>these factors mostly offset each other, all other
> >>benefits (rim protection, ride quality, wear life,
> >> to the wider tire.
> >
> >This depends on how much one weighs and what sort
> > of roads the person is riding on.
In my observation, the road surface has a much bigger role in
dictating the appropriate minimum tire size. It is true that fatter
tires usually have a higher weight rating, and when the rider's weight
goes high enough, this becomes a consideration.
> And also the speeds at which the person is riding.
The faster you ride, the more you need in terms of rim protection,
shock absorption, wear resistance, pinch flat resistance, and
traction. So the faster you go, the more you can benefit from a wider
tire.
Chalo
John Forrest Tomlinson
<chalo....@gmail.com> wrote:
>
>The faster you ride, the more you need in terms of rim protection,
>shock absorption, >wear resistance, pinch flat resistance, and
>traction. So the faster you go, the more you can benefit from a wider
>tire.
I can see that for traction, though very few people go near the limits
of traction on moderatley narrow tires.
But why dod you need more for rim protection when going fast? Or
shock absorbtion? Or wear resistance?
And more to the point, do people trying to go fast care about a little
extra shock absorbtion?
When I'm going fast there's more weight on my legs and less on my
hands and butt, so I notice shocks less than when just rolling along
slowly.
And Chalo - I have a couple friends who weigh 100-105 lbs. In your
scheme of things, are they allowed to ride 23s or woudl you tell them
they'd be better off riding 25s or larger? Not knowing them or their
riding goals. Well?
Carl Sundquist
> John Forrest Tomlinson wrote:
>> John Forrest Tomlinson wrote:
>>> Chalo wrote:
>>>> Instrumented tests have shown that for tires of
>>>> equal construction, wider tires have slightly less
>>>> rolling resistance at the same pressure. Narrower
>>>> tires have slightly less aerodynamic drag. While
>>>> these factors mostly offset each other, all other
>>>> benefits (rim protection, ride quality, wear life,
>>>> pinch flat resistance, traction)give the advantage
>>>> to the wider tire.
>>> This depends on how much one weighs and what sort
>>> of roads the person is riding on.
>
> In my observation, the road surface has a much bigger role in
> dictating the appropriate minimum tire size. It is true that fatter
> tires usually have a higher weight rating, and when the rider's weight
> goes high enough, this becomes a consideration.
Yes, we know that you have special considerations where weight is a
concern. But in that regard, you are an outlier. We all have personal
agendas though. I, for one, tend to think generally from sporting angles
rather than utilitarian, though I do love the utilitarian aspect of my
bikes.
Sandy
news:f10a689b-053e-4860...@n33g2000pri.googlegroups.com...
>
> The faster you ride, the more you need in terms of rim protection,
> shock absorption, wear resistance, pinch flat resistance, and
> traction. So the faster you go, the more you can benefit from a wider
> tire.
>
> Chalo
I am not convinced from my experience. Those who are going faster are
lighter, when you look at broad rider weight categories. I think that's
quite obvious, but maybe you disagree. Shock absorption matters little in
racing. Crossing a pothole faster means less drop, so less likelihood of
pinch flats, not to mention that higher pressure likely allows greater
resistance to the deformations leading to them. (I can't recall a single
incident of flatting while crossing low traffic circles, and fast riders
don't ride into curbs regularly.) Wear resistance is not really a big
consideration _in racing_ so budget accordingly. And when you accumulate
all the small weight savings on a bike weighing 10 kg against one weighing 8
kg, it makes for a competitive difference.
If by "fast" you were aiming at 14 mph rather than 11 mph, then I am not
sure my observations apply.
--
Bonne route !
Sandy
Verneuil-sur-Seine FR
Nick L Plate
painful if you're 3+ hours in the saddle. Rider fatigue caused by
constant road shock will slow you more over a long ride, than a less
than optimum aero tyre/rim combination.
If you 'need' narrow tyres, use tubs, a 23mm tub is more comfortable
and grips better in the corners(than 25mm wired) due to a longer
contact patch at an appropriate riding pressure. Steering response
will also become less jittery with a short trail set up. Confidence
in cornering over rough surfaces improves reducing rider tension and
improves speed through corners.
carl...@comcast.net
<usenet...@jt10000.com> wrote:
>On Thu, 29 Jan 2009 10:12:44 -0800 (PST), Chalo
><chalo....@gmail.com> wrote:
>
>>
>>The faster you ride, the more you need in terms of rim protection,
>>shock absorption, >wear resistance, pinch flat resistance, and
>>traction. So the faster you go, the more you can benefit from a wider
>>tire.
>
>I can see that for traction, though very few people go near the limits
>of traction on moderatley narrow tires.
>
>But why do you need more for rim protection when going fast?
[snip]
Dear John,
The faster the hammer hits the nail, the deeper the nail goes into the
wood.
More rim protection is needed at higher speeds because impact roughly
corresponds to kinetic energy, which is half the mass times the square
of the velocity--it rises even faster than the speed.
At 20 mph, a rider hits a chunk of gravel (oops!) with an impact of
20^2 whomps, or 400 whomps.
At 25 mph, the same rider hits the same chunk of gravel at 25^2
whomps, or 625 whomps.
At 30 mph, he hits it at 30^2 whomps, or 900 whomps, more than twice
as hard.
That's why drivers slow down on rough roads and why faster riders get
more pinch flats on bicycles.
Cheers,
Carl Fogel
Jay Beattie
wrote:
> On Thu, 29 Jan 2009 10:12:44 -0800 (PST), Chalo
>
It's funny. I remember when 23mms were considered fat. We were
racing on 19mm and 20mm clinchers or on sewups (my racing weight
187-195). When I switched to 23s, it made a difference, but that was
probably because I changed over to team supplied Conti 23s that were
probably 25s. They were squishier, and I didn't like them (yah, I
know that is impossible if both tires had the same inflation pressure
-- but it was squishier).
Also, the difference between 23mm and 25mm is sometimes just a label
-- being that nominal sizes are often wrong. I have found differences
in tires of the same size, though. For example, a 23mm kevlar belted
bomb-proof tire like a Bontrager Hardcase will not roll as well as a
23mm ProRace. Whether that affects your result in a race is hard to
say.
I use big fat tires during winter (28-35mm) because they give me
better traction on wet pavement and more float in the post-snow
gravel. They do not ride like 23mm ProRaces, and the penalty is
significant IMO -- particularly slogging through the hills. I would
not ride them in a race except maybe a cross race on packed dirt.- Jay
Beattie.
Keiron
> jeffreybike wrote:
>>
>> Is there any real difference between 23mm and 25mm tires as far as
>> speed. Will 2mm make you that slower or faster?
>
> There is no significant difference in speed between those two sizes of
> tire. Too narrow a tire will slow you down quite a lot when you get a
> pinch flat and have to stop and repair it.
>
> Instrumented tests have shown that for tires of equal construction,
> wider tires have slightly less rolling resistance at the same pressure.
--snip--
According to Sheldon this is rather moot as generally speaking wider tyres
at the same pressure are over inflated or narrow tyres at a same pressure
to wider ones will be under inflated (and so not being used optimality
presumably). As I understand it anyway. Might not be that relevant with
the 2mm difference but just throwing out there.
Having said that: in reality little difference in speed I suppose.
John Forrest Tomlinson
<tj-...@blueyonder.co.uk> wrote:
>Confidence
>in cornering over rough surfaces improves reducing rider tension and
>improves speed through corners.
Good point.
pm
Additionally, at equal pressures a wider tire will give a _worse_ ride
than a narrower tire. (consider how the size and shape of the contact
patch varies with the amount of compression)
-pm
Frank Krygowski
>
> Also, the difference between 23mm and 25mm is sometimes just a label
> -- being that nominal sizes are often wrong. I have found differences
> in tires of the same size, though. For example, a 23mm kevlar belted
> bomb-proof tire like a Bontrager Hardcase will not roll as well as a
> 23mm ProRace. Whether that affects your result in a race is hard to
> say.
I think it's well documented that Kevlar belts increase rolling
resistance significantly. It's something I noticed and disliked. In
fact, I gave away a set of belted tires because they felt so dead to
me.
- Frank Krygowski
Chalo
>
> Chalo wrote:
>
> >The faster you ride, the more you need in terms of rim protection,
> >shock absorption, >wear resistance, pinch flat resistance, and
> >traction. So the faster you go, the more you can benefit from a wider
> >tire.
>
> I can see that for traction, though very few people go near the limits
> of traction on moderatley narrow tires.
>
> But why dod you need more for rim protection when going fast? Or
> shock absorbtion? Or wear resistance?
Because the energy contained in bumps goes up as the square of the
speed. It's four times easier to pinch flat or flat spot a rim at
30mph than at 15mph.
> And more to the point, do people trying to go fast care about a little
> extra shock absorbtion?
Why wouldn't they? Every watt of muscle power they spend absorbing
bumps is a watt that doesn't make them go any faster.
http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm
http://davesbikeblog.squarespace.com/storage/Speed04.jpg
http://www.fredrompelberg.com/upload/algemeen/Wereldrecord_fiets.JPG
These are bikes which went very fast indeed, for which rolling
resistance was a primary limiting factor in the speeds they reached,
and which used both fat tires and front suspension even though they
rode on one of the smoothest, least blemished surfaces available
anywhere.
> And Chalo - I have a couple friends who weigh 100-105 lbs. In your
> scheme of things, are they allowed to ride 23s or woudl you tell them
> they'd be better off riding 25s or larger? Not knowing them or their
> riding goals.
If they ride on the streets I ride on, the smallest I could recommend
is 28mm. That's what my wife uses, and she rides about as slowly and
sedately as any able-bodied person could. For much smoother and
better maintained streets, perhaps a narrower tire would be
acceptable.
Chalo
John Forrest Tomlinson
<chalo....@gmail.com> wrote:
>> And Chalo - I have a couple friends who weigh 100-105 lbs. In your
>> scheme of things, are they allowed to ride 23s or woudl you tell them
>> they'd be better off riding 25s or larger? Not knowing them or their
>> riding goals.
>
>If they ride on the streets I ride on, the smallest I could recommend
>is 28mm. That's what my wife uses, and she rides about as slowly and
>sedately as any able-bodied person could.
OK I have to say it - you're a dogmatic idiot on tire size. To make
such a suggestion based on your wife, w/o knowing them. The correct
answer to my question is some other questions: "What kind of riding
are they doing? On what roads? What are their goals." Not some huge
boy dogma.
Why TF should people who weigh 100 pounds and compete in some of the
toughest bike races in the US use 28s? It's absurd. It's saying "I
want to do worse than I can."
John Forrest Tomlinson
<chalo....@gmail.com> wrote:
>> But why dod you need more for rim protection when going fast? Or
>> shock absorbtion? Or wear resistance?
>
>Because the energy contained in bumps goes up as the square of the
>speed. It's four times easier to pinch flat or flat spot a rim at
>30mph than at 15mph.
Bumps have only a horizontal component? Interesting.
John Forrest Tomlinson
<chalo....@gmail.com> wrote:
>> And more to the point, do people trying to go fast care about a little
>> extra shock absorbtion?
>
>Why wouldn't they? Every watt of muscle power they spend absorbing
>bumps is a watt that doesn't make them go any faster.
>
>http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm
>http://davesbikeblog.squarespace.com/storage/Speed04.jpg
>http://www.fredrompelberg.com/upload/algemeen/Wereldrecord_fiets.JPG
Interesting. And all the bike racers who do well around the world on
fairly narrow tires are choosing the wrong equipment I suppose?
John Forrest Tomlinson
>At 20 mph, a rider hits a chunk of gravel (oops!) with an impact of
>20^2 whomps, or 400 whomps.
>
>At 25 mph, the same rider hits the same chunk of gravel at 25^2
>whomps, or 625 whomps.
>
>At 30 mph, he hits it at 30^2 whomps, or 900 whomps, more than twice
>as hard.
Interesting. I would have thought there woudl be some vertical
componenent in many pinch flats regardless of speed, but then I don't
know much about physics and you clearly do.
bjwe...@gmail.com
> John Forrest Tomlinson wrote:
>
> > Chalo wrote:
>
> > >The faster you ride, the more you need in terms of rim protection,
> > >shock absorption, >wear resistance, pinch flat resistance, and
> > >traction. So the faster you go, the more you can benefit from a wider
> > >tire.
>
> > I can see that for traction, though very few people go near the limits
> > of traction on moderatley narrow tires.
>
> > But why dod you need more for rim protection when going fast? Or
> > shock absorbtion? Or wear resistance?
>
> Because the energy contained in bumps goes up as the square of the
> speed. It's four times easier to pinch flat or flat spot a rim at
> 30mph than at 15mph.
How do you know that likelihood of pinch flatting
goes up as the kinetic energy?
I'm not trying to get involved in flaming over tires.
You and JFT have opinions and are entitled to them.
But it drives me a little nuts when people on RBT
assert that something scales as such-and-such
without proof. In this case, it seems at least possible
to me that likelihood of pinch-flatting goes as the
momentum, linearly with velocity.
I have not worked it out in detail, but it seems plausible
that the compression of a tire hitting a bump or
edge is linear with the momentum and inversely
proportional to the tire pressure (and of course
the tire has to compress by roughly one diameter
to pinch flat, so larger tires resist better).
Ben
carl...@comcast.net
<usenet...@jt10000.com> wrote:
>On Thu, 29 Jan 2009 13:31:29 -0700, carl...@comcast.net wrote:
>
>>At 20 mph, a rider hits a chunk of gravel (oops!) with an impact of
>>20^2 whomps, or 400 whomps.
>>
>>At 25 mph, the same rider hits the same chunk of gravel at 25^2
>>whomps, or 625 whomps.
>>
>>At 30 mph, he hits it at 30^2 whomps, or 900 whomps, more than twice
>>as hard.
>
>Interesting. I would have thought there woudl be some vertical
>component in many pinch flats regardless of speed, but then I don't
>know much about physics and you clearly do.
Dear John,
It's a tricky situation to model.
There's always a vertical component.
The simplest example is something that sticks up vertically, like a
chunk of gravel, a stone, the lip of a nasty crack, a jutting
cobble-stone, a small branch, or a piece of automotive debris. The
faster you go, the harder you hit these things, the more likely you
are to pinch-flat or damage a rim.
The opposite example is a hole of some kind--a wide crack or a
pothole. They provide the kind of vertical component and complication
that you may be thinking of, namely how far the wheel drops down.
At a really slow speed with a big enough hole, the wheel just rolls
down one side, across the bottom, and up the other side, without much
trouble.
At a faster speed with a wide enough hole, you start to fly off the
near edge of the hole and land on the bottom. There's more impact
here, but a smooth landing isn't likely to damage things.
Go a little faster into a narrower hole, and you fly off the edge,
drop toward the bottom, and slam into the base of the far side of the
hole as if it's a wall--ouch! Damage is much more likely.
At higher speeds, the good thing is that you don't drop as far down
into the hole, so you hit higher up on the far side, effectively
reducing the height of the obstacle and making things more gentle.
The bad thing is that you're hitting higher up, but much harder--the
higher speed that reduced how far you dropped raises the impact with
the square of the velocity. Ouch!
Every year, the cobblestones of Paris-Roubaix illustrate the problem.
The riders go like crazy over badly-mismatched chunks of stone and
pretty much expect to pinch-flat and crash.
Sometimes they talk about getting up enough speed to smooth things out
on certain stretches. If you go fast enough, you may skim over the
nasty cracks and avoid pinch flats.
Unfortunately, you also lose some control when the tire is in the air.
With dozens of cobblestones coming the riders at 30 to 40 feet per
second, crashes are routine in Paris-Roubaix, even for riders who can
do the whole Tour de France without any road rash.
One reason those pros like tubulars is that the rounded rim of a
tubular reduces the chance of a pinch flat, compared to the flange
sticking up on a clincher.
Pros have to worry more about pinch flats because they go faster and
thus hit things harder than slower ordinary riders.
Pros also can expect more pinch flats because they have less time to
react and avoid hitting things. Road hazards come at them faster, and
only the lead rider has a clear view of what's coming up. Anyone
drafting has to hope that the lead rider picks a smooth path--and pay
constant attention to the wheel a foot or so in front of him.
And pros naturally want the narrowest tires and thinnest tread and
tubes, which make pinch flats more likely. Road racing produces more
failures because the riders are going faster and insisting on lighter
components.
Of course, pros probably avoid many pinch flats that would victimize
ordinary riders because pros usually have better reflexes, pay more
attention, and have more experience. The rider who puts in 20,000
miles a year at high speeds next to other racers is probably better at
handling potholes than the guy who commutes 5,000 miles a year at
lower speeds, often daydreaming.
The other thing that helps the pro peloton avoid pinch flats is that
they usually race on good roads and can use the whole width of the
road, which is even swept nowadays for some events like the Tour de
France.
Cheers,
Carl Fogel
Chalo
>
> Chalo wrote:
> >
> >>
> >> And more to the point, do people trying to go fast care about a little
> >> extra shock absorbtion?
> >
> >Why wouldn't they? Every watt of muscle power they spend absorbing
> >bumps is a watt that doesn't make them go any faster.
> >
> >http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm
> >http://davesbikeblog.squarespace.com/storage/Speed04.jpg
> >http://www.fredrompelberg.com/upload/algemeen/Wereldrecord_fiets.JPG
>
> Interesting. And all the bike racers who do well around the world on
> fairly narrow tires are choosing the wrong equipment I suppose?
How would one know whether they were using the optimum size? When was
the last time a pro road racer used 700x28s other than on
cobblestones?
Major Taylor used roughly 1.5" (38mm) tires. and he was racing on
highly groomed 'dromes and board tracks. I reckon he wanted to win
races too.
Chalo
>
> Chalo wrote:
> >
> >>
> >> But why dod you need more for rim protection when going fast? Or
> >> shock absorbtion? Or wear resistance?
>
> >Because the energy contained in bumps goes up as the square of the
> >speed. It's four times easier to pinch flat or flat spot a rim at
> >30mph than at 15mph.
>
> Bumps have only a horizontal component? Interesting.
Do you think the speed of travel has nothing to do with the vertical
rate of acceleration of a bump?
Chalo
>
> Chalo wrote:
> >
Why should they opt into a more punishing ride, sapping more of their
strength and inducing more fatigue than necessary, just to reap a few
grams of weight reduction? A larger tire provides a measure of
suspension that as any motorcyclist will attest is essential for going
fast.
Chalo
carl...@comcast.net
Dear Chalo,
Unfortunately, citing racers' equipment is a double-edged sword.
All too often, we have no real evidence whether they won because or in
spite of their equipment.
Here's a nice 1898 photo of Major Taylor, a fearsome racer in events
around the world at the turn of the century, showing what would be
considered ridiculous balloon tires:
http://www.ltolman.org/chainless-b2.jpg
Racing tires of that era tended toward the notion that if a little is
good, a lot is better. The pneumatic tire had been invented only ten
years earlier, in 1889, and replaced the solid and hollow-cushion
tires in a year or so, partly because of the comfort and partly
because of Dunlop's original reason for trying inflation--they roll a
hell of a lot faster than solid tires.
But if you look at that photo again, you'll see that Major Taylor was
riding on a Sager roller-pin chainless shaft-drive bicycle, which has
a lower transmission efficiency than a chain. Taylor won races, as far
as anyone can tell, in spite of the handicap of a shaft drive.
Here's another photo of Taylor:
http://www.virginmedia.com/digital/galleries/techbikes.php?ssid=2
Don't worry about the tire size, which is hard to make out. Look at
the frame. That's a quad-stay Eagle design, with two chainstays.
Here's a page with lots of photos of a quad stay:
http://www.theracingbicycle.com/Eagle.html
http://www.theracingbicycle.com/images/Eagle_Quad_stays.jpg
Whatever slight stiffness might have been gained was probably more
than offset by the extra weight.
And here's Taylor with an even stranger bit of equipment, during his
triumphant tour down under:
http://i23.tinypic.com/jqqhcx.jpg
It's hard to see how that projecting front gear could do anything
except increase transmission losses and add weight.
Like many racers, Taylor was perfectly willing to try odd equipment,
partly in hopes of finding something that worked better and partly in
certainty that a sponsor would pay him.
Over the years, shaft drive was dropped for racing, extra chainstays
vanished, oddball projecting gears never appeared north of the
equator, and racing bicycle tires got narrower and narrower
Things are often more complicated than they seem. The wider, cushier
tire sounds like a good idea that would lose less power through better
suspension and lower rolling resistance. But the extra wind drag of
the wider tires (and frames) seems to outweigh such gains in
high-level racing.
Here's Sam Whittingham talking about the complications of the tires
used on the Varna Diablo:
"In 1998, in Montreal at the PMG test track we had the luxury of
testing many things over the few weeks we were there including
different tire configurations. John Tetz showed us how to do some low
speed roll down tests that transferred quite well to the higher speeds
(60mph)."
"At that time we found the best rolling tire to be a continental tempo
track tubular at 175psi ($100) we still use this on the back of
Diablo. Last year when I went 81mph we tried some Vittoria track
tubulars ($125) because they pumped up to 240psi. We gave up on them
because they were as much as 1/4 inch out of round!"
"The tire that performed almost as well and has been my front tire for
7 years is a panaracer technova clincher at 135psi ($11.99) very
cheap! This is also one of the roundest tires I have ever found.
Obviously cost has nothing to do with performance!"
"We also tested the tufo tires. They seemed like the perfect solution.
They could take ridiculous amounts of pressure. Because they are
rolled in there construction rather than sewed they are the most round
and uniform tire I've ever seen. They also have sturdy side walls and
are reasonably inexpensive. Seems perfect right? One big flaw, slow as
molasses. I was as much as 4 mph slower on these tires even at
200psi."
"I spent a few days trying to top 96km/h in Montreal. I switched to
the panaracers and immediately went 101km/h several times. This was
shown in our rolldown test as well when I rolled nearly 50% further on
the cheap panaracers. Even on my road racing bike I could feel that
the tufo's were sluggish."
"I soon realized that you could easily guess a tire's rolling
resistance by the suppleness of the sidewall. The lighter and more
flexible the faster it rolls. Problem is, it doesn't give you much
room for scrubbing the fairing. So to go fast you need a tire with an
inherently fragile sidewall and pray you don't knick it. Hence, my
80mph blow-out It was one of my beloved panaracers that gave out on
me. Several factors caused this:"
"First: the tire was old. We also found older tires roll better.
probably because the sidewalls have broken down a little. We had
checked it before every run and it was still good but not great. I
could see some threads starting to fray, but nothing I considered
dangerous."
"Second: The pressure on the side said 125psi we were running them at
175psi. We had tested several the panaracers at over 200psi for
several days with no bulging or any deterioration. We ran at 175psi
all week and the tires were fine after every run. Slightly larger but
still round."
http://www.recumbent-bikes-truth-for-you.com/newsletter-october-2003.html
I think that the 24" Panaracer Tecnova was 25 mm or even wider.
Cheers,
Carl Fogel
John Forrest Tomlinson
>It's a tricky situation to model.
>
>There's always a vertical component.
Dear Carl,
I was surpised that someone as good as physics left it out earlier but
I assume you did that to simplify the subject for simple people like
me.
Thank you.
John Forrest Tomlinson
>The other thing that helps the pro peloton avoid pinch flats is that
>they usually race on good roads and can use the whole width of the
>road, which is even swept nowadays for some events like the Tour de
>France.
Dear Carl.
You again demonstrate a lack of knowledge of bike racing.
Cheers,
John Forrest Tomlinson
<chalo....@gmail.com> wrote:
>Why should they opt into a more punishing ride, sapping more of their
>strength and inducing more fatigue than necessary, just to reap a few
>grams of weight reduction? A larger tire provides a measure of
>suspension that as any motorcyclist will attest is essential for going
>fast.
>
Dear Chalo,
Is there any possible answer that will satisfy a big boy like that
some people can ride 23s? It seems not.
You know, we can learn a lot from outliers like you, but your dogma
about it is really unfortunate.
John Forrest Tomlinson
Hahaha. You're flailing now.
You pull out a handful of examples of bike racers to support your
argument, and then when I pull out massive numbers of bike racers to
support mine you question their decisions. Lame.
In a competitive endeavour, if large number of people, particularly
the people doing something successful, make a certain choice, in the
absense of firmer evidence to the contrary, their choice is almost
certainly correct.
John Forrest Tomlinson
>Unfortunately, citing racers' equipment is a double-edged sword.
>
>All too often, we have no real evidence whether they won because or in
>spite of their equipment.
Yes, so far better to rely on the clear thinking ideas of a person who
as far as we know has zero practical experience in bike racing as a
rider, coach, mechanic, or any other capacity such as Carl Fogel.
But perhaps I misspoke, and should clarify things:
Carl, do you have any practical experience in bike racing whatsoever?
And if so, did you achieve success of any kind?
Clive George
>> Why TF should people who weigh 100 pounds and compete in some of the
>> toughest bike races in the US use 28s? It's absurd. It's saying "I
>> want to do worse than I can."
>
>Why should they opt into a more punishing ride, sapping more of their
>strength and inducing more fatigue than necessary, just to reap a few
>grams of weight reduction? A larger tire provides a measure of
>suspension that as any motorcyclist will attest is essential for going
>fast.
Maybe there was an element of superstition in tyre choice for pros a while
back. But if you reckon that people in a sport notorious for trying almost
anything to get a couple of seconds, with the backup of quite a lot of
actual measuring, haven't considered different tyres in the quest for speed,
I reckon you're probably a bit deluded ;-)
(the answer to your question would be "because it's faster", and not just
because of weight reduction)
russell...@yahoo.com
wrote:
> On Fri, 30 Jan 2009 00:46:50 -0700, carlfo...@comcast.net wrote:
> >Unfortunately, citing racers' equipment is a double-edged sword.
>
> >All too often, we have no real evidence whether they won because or in
> >spite of their equipment.
>
> Yes, so far better to rely on the clear thinking ideas of a person who
> as far as we know has zero practical experience in bike racing as a
> rider, coach, mechanic, or any other capacity such as Carl Fogel.
And how many of the bikes or equipment used by Armstrong was designed
by a professional bike racer or director? None. It was designed by
engineers who likely know how to ride a bike assigned to the job by
Trek or some other company. Having specific experience is
unnecessary. How many Nascar cars or Goodyear tires are designed by
people who have driven at 200 mph on 45 degree banked tracks? None.
Where do you get this idea that a person needs specific experience to
make something? Oppenheimer was not a pilot or soldier so he should
not have been able or qualified to make an atomic bomb.
dusto...@mac.com
> It's a tricky situation to model.
> Every year, the cobblestones of Paris-Roubaix illustrate the problem.
> The riders go like crazy over badly-mismatched chunks of stone and
> pretty much expect to pinch-flat and crash.
Not that they want to, of course <g>.
> Sometimes they talk about getting up enough speed to smooth things out
> on certain stretches. If you go fast enough, you may skim over the
> nasty cracks and avoid pinch flats.
You go as fast as you can and lift over the big stuff, or when the guy
ahead of you lifts, if you can't see exactly what he lifted for.
Do it right, you can ride over/through anything.
> Unfortunately, you also lose some control when the tire is in the air.
> With dozens of cobblestones coming the riders at 30 to 40 feet per
> second, crashes are routine in Paris-Roubaix, even for riders who can
> do the whole Tour de France without any road rash.
Sometimes you don't make it. Doesn't mean you won't the next time <g>.
> One reason those pros like tubulars is that the rounded rim of a
> tubular reduces the chance of a pinch flat, compared to the flange
> sticking up on a clincher.
IME it takes a fat clincher tire to have the pop resistance of a 23mm
tubular like the late lamented Vittoria CG (moment of silence). Like,
at least 25mm, maybe 28mm, about the size of the Specialized Touring
II "1-1/8" I used to use on the dirts when not riding sewups. Size,
plus the thick, inflexible sidewalls those things had. Slow tires, no
wet pavement traction, but tough and cheap, and "when they (sewup
riders) started popping, I started popping".
> The other thing that helps the pro peloton avoid pinch flats is that
> they usually race on good roads and can use the whole width of the
> road, which is even swept nowadays for some events like the Tour de
> France.
To the best of my knowledge, the only "sweeping" in pro road races is
done by lead vehicles. And the broom wagon <g>.
As an American (USA) Cat III Forever parking-lot racer, the few times
I've been in a real, open road race were really *eye* opening-- junk
in the road, glass, nails, badly angled seams, potholes, all of the
real stuff out there, and "deal with it". Terrifying, gives you a good
look at what the pros really have to live with and another measure of
respect for their abilities. IOW, not a football field or a golf
course <g>.
I've ridden 23's while weighing over 240lbs on ordinary country
roads-- some fairly rough, few really smooth, with no problems, at
115lbs max inflation pressure. SWMBO used to use my race-prize 20mm
tires back in the day, and she had exactly one flat in a fair amount
of country road riding with me and with me and the boys (not during
the heavy dirt road riding era) that was a puncture, not a pop. I
couldn't ride those tires across sidewalk cracks without popping (from
experience. Hey, they were "free"!).
I put a 25mm Conti on the back of my "usual" bike a few weeks ago. A
little more protection, not much ride diff. We've been exploring on
the Sunday rides recently, nothing like searching for and riding the
gnarliest dirts as in the salad days but we've seen a few stretches of
"unpavement" including some rocky gravel. Kinda fun, and if I ever get
around to using my (Christmas present) bike shop gift card, I'll put a
25 on the front, too just for grins. NBD. I don't think a 28mm tire
will fit (Litespeed Catalyst) at least in the back but I don't need a
28 for these rides, and I've ridden 28's in my time and don't unless I
need to, because the smaller tires ride better for my use. --D-y
carl...@comcast.net
Dear John,
As usual, it was only left out in your imagination.
Cheers,
Carl Fogel
carl...@comcast.net
Dear John,
Ah, your usual signal that you have no argument!
Cheers,
Carl Fogel
Chalo
>
> Chalo wrote:
> >
> > JFT wrote:
> >>
> >>
> >> toughest bike races in the US use 28s? It's absurd. It's saying "I
> >> want to do worse than I can."
>
> >Why should they opt into a more punishing ride, sapping more of their
> >strength and inducing more fatigue than necessary, just to reap a few
> >grams of weight reduction? A larger tire provides a measure of
> >suspension that as any motorcyclist will attest is essential for going
> >fast.
>
> Maybe there was an element of superstition in tyre choice for pros a while
> back. But if you reckon that people in a sport notorious for trying almost
> anything to get a couple of seconds, with the backup of quite a lot of
> actual measuring, haven't considered different tyres in the quest for speed,
> I reckon you're probably a bit deluded ;-)
>
> (the answer to your question would be "because it's faster", and not just
> because of weight reduction)
I really doubt measurement has much to do with it. As I've pointed
out, early 20th century racers used tires about 1.5" wide on their
bikes, thinking that was faster than the alternatives. Twenty years
ago, many racers were using 19s and 20s on their bikes, thinking that
was faster. Now they're using 23s, thinking that's faster.
Is every such fashion change for the faster? How could it be? But
that's the nature of fashion-- as long as everybody adopts it, then
you never have to know one way or the other. I'm sure that if Lance
in his heyday had used 700x18s and won on them, everybody else would
have switched to those. And if he'd used 700x32s and won on them,
everybody would have switched to those.
The truth of the matter is that Lance probably could have run anything
short of knobbies and won the races he did, by maintaining his mental
and physical and tactical advantage. It's the mental advantage that
racers don't want to concede to their opponents by using something
that is perceived, correctly or incorrectly, as slower equipment.
Thus we'll never really know whether a high quality race tire built
in 28mm or 32mm casing width would be as fast in races as 23mm or 25mm
tires. If anyone demonstrates racing success with an unorthodox tire
size-- whether or not that success is related to the tires-- the
entire population of racers will switch to the novel size.
Chalo
Clive George
>Thus we'll never really know whether a high quality race tire built
>in 28mm or 32mm casing width would be as fast in races as 23mm or 25mm
>tires. If anyone demonstrates racing success with an unorthodox tire
>size-- whether or not that success is related to the tires-- the
>entire population of racers will switch to the novel size.
I really think you're underestimating the effort people go to to work such
things out. There are people out there spending a lot of time with wind
tunnels etc trying to squeeze seconds for races. It's more pertinent for
stuff against the clock (TTs, pursuits, etc), but that's quite strong over
here.
Sure, the superstitious mentality you're describing exists, but at the very
top level it is backed up by actual research.
Ryan Cousineau
"Clive George" <cl...@xxxx-x.fsnet.co.uk> wrote:
> "Chalo" <chalo....@gmail.com> wrote in message
> news:12afe23d-acf6-470a...@o40g2000prn.googlegroups.com...
>
> >Thus we'll never really know whether a high quality race tire built
> >in 28mm or 32mm casing width would be as fast in races as 23mm or 25mm
> >tires. If anyone demonstrates racing success with an unorthodox tire
> >size-- whether or not that success is related to the tires-- the
> >entire population of racers will switch to the novel size.
<http://www.bikeradar.com/road/news/article/bikes-of-paris-roubaix-fair-w
eather-friends-15792>
Pozzatto had a spare bike set up with 27mm Vittoria tubular tires for
the 2008 Paris-Roubaix. Conditions on the day were dry, and he never
used it. So the experiments are there.
The notable counterexample of your theory was the era of the Roubaix
suspension forks. DuClos-LaSalle won the race on a Rock Shox fork
(Paris-Roubaix or Ruby; I'm not sure which model), other elite riders
used them.
Then they stopped. Today, there are still some experiments with
suspension, but they are modest: Specialized's rubber inserts in forks
and chainstays, Trek's curious soft-tail OCLV, built for the 2005 race:
<http://www.cyclingnews.com/road/2005/apr05/roubaix05/tech/?id=/tech/2005
/features/hincapie_bike>
Further tales of suspension at Roubaix:
<http://www.cyclingnews.com/tech.php?id=tech/2005/news/04-27>
> I really think you're underestimating the effort people go to to work such
> things out. There are people out there spending a lot of time with wind
> tunnels etc trying to squeeze seconds for races. It's more pertinent for
> stuff against the clock (TTs, pursuits, etc), but that's quite strong over
> here.
>
> Sure, the superstitious mentality you're describing exists, but at the very
> top level it is backed up by actual research.
I think there's another thing going on. In the era of the fattest
balloon tires, aside from everything else, the fat tires may have been
faster over the often-unpaved roads of the day.
In the era of 19mm tires, it was an experiment that was down to a lack
of evidence. I don't know how fast the trickle of information was, but
it appears at some point tires evolved back to the 23mm range of today.
As much as anything, that may speak to the subtlety of the advantages.
Meanwhile, there's been a lot of aerodynamic research in bike racing the
last decade or so. Both TT bikes and road bikes (and most notably,
individual riders, thanks to position tuning) have benefitted, but it
means that a lot of the questions about tire widths today come down to
"what's aerodynamic?"
The reason is that racers can live with 21-23mm tires most days, can
switch wheels easily when it's not possible, and want to optimize for a
wheelset (including the tires and their widths) that is as aero as
possible, as light as possible, and as durable as possible, and of
course within the project budget. So far, 23mm seems to be the current
answer.
Amateur racers tend to ape pro racing choices, but the reason isn't just
fashion: absent big budgets to test aerodynamics themselves, all an
amateur can do is trust in the implicit results from better-backed
riders, and emulate same. There's also some reading and some home-brewed
techniques (photographic frontal-area analysis is cheap and clever) that
will pay performance dividends for the amateur TTist. Yes, it's just a
hobby, but it's not a bad one.
In conclusion: conditions change, technologies change, and so does
equipment. Bike racers will try almost anything once. Bad ideas tend to
fall away, sometimes quickly, sometimes slowly. The most likely reason
that most pros don't use 27mm tires is because they're slower than 23mm
tires.
--
Ryan Cousineau rcou...@gmail.com http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."
Ryan Cousineau
John Forrest Tomlinson <usenet...@jt10000.com> wrote:
JT:
I've raced. I've driven mechanical support vehicles in races. As a
neutral support vehicle mechanic, I've changed a wheel for a racer
(badly). I've won races, albeit pointless amateur low-cat ones. I've
done all the mechanical work on all my racing bicycles. I've ridden
road, crits, TTs, track (not in competition yet), cyclocross, mountain
bikes, and if it wasn't for the narrow-mindedness of the local racing
association, would have raced cyclocross on a tandem. I've built up a
Giant TCR 0 from a frame and a bunch of boxes of Dura-Ace parts. Are my
bona fides sufficient?
I agree with Carl's claim that "all too often, we have no real evidence
whether [racers] won because or in spite of their equipment."
Any questions?
carl...@comcast.net
Dear Clive,
I'm inclined to agree with you . . .
But then I ask myself where the actual research is?
That is, do you have any links to actual research that shows that an
actual rider on a reasonably normal road course is measurably faster
on 20, 23, or 25 mm tires?
I mean actual results for a real rider over an hour or more on a road
surface, to overcome the many complications of road surface versus
smooth drum, wider tire wind drag, frame size affecting aerodynamics,
tire pressure, rider fatigue, and so on.
The more I think about it, the more that I wonder if there are no such
tests. The kinds of differences predicted by isolated theory and
laboratory tests might well be lost in the noise.
Heck, it isn't usually even possible to find out what tire pressures
are actually used in the TDF. And the riders, who tend to stay in the
same pack most days, use a wide variety of tires (often re-badged to
suit their preferences), despite any lab test results indicating which
one has the best theoretical rolling resistance.
Come to think of it, is there a lot of research that shows that 700c
tires, front and rear, are the very best height for speed on
traditional road bicycles?
Cheers,
Carl Fogel
Clive George
news:87r6o4h09r5thq0a3...@4ax.com...
>>Sure, the superstitious mentality you're describing exists, but at the
>>very
>>top level it is backed up by actual research.
>
> Dear Clive,
>
> I'm inclined to agree with you . . .
>
> But then I ask myself where the actual research is?
Well, I do know that the GB track team were researching lots of things, and
I also know they're darned secretive.
Ben C
[...]
> I really doubt measurement has much to do with it. As I've pointed
> out, early 20th century racers used tires about 1.5" wide on their
> bikes, thinking that was faster than the alternatives.
The roads were probably a bit rougher back then.
carl...@comcast.net
Dear Clive,
Hmmm . . . track teams, not road teams.
Still, it would be interesting to know whatever they learned in their
research.
An often-overlooked problem with the popularity-contest approach to
technology in bicycling (all the racers do it, so it must be right) is
the self-reinforcing nature of the game.
Every racer starts out as an amateur.
He naturally imitates whatever the fastest riders are doing. The more
interested he is, the more detail he puts into his imitation, until he
ends up preferring a particular brand of chain oil, carbon fork, or
spoke.
Whether the chain oil, fork, or spoke-brand has any effect on speed,
good or bad, is not something that can be easily determined, since so
many factors affect speed.
Curiously, the smaller the theoretical improvement, the more
vehemently people will insist on it and its importance, particularly
if there's no actual evidence that it exists.
Ceramic bearings are a fairly good example of the process. For bicycle
wheels, despite some amazing claims, it seems likely that the alleged
improvements are due more to the drag of the rubber dust covers than
anything else, but we'll never convince people of this if they're
desperate for any advantage, no matter how tiny, and afraid that
someone will beat them by spending a few hundred dollars on what must
obviously be a secret weapon.
For some reason, the argument that something must be the best because
it's preferred by the vast majority of experts/pros/users is rarely
applied on RBT to computer operating systems.
I'd still like to think that you're right and that 23 mm is the best
choice for going fast at the pro level in road racing--it was 23 mm,
wasn't it, not 21, 22, 24, or 25, right?)
But if so, I suspect that it was arrived at by an evolutionary
process, not any research.
Cheers,
Carl Fogel
Chalo
>
> Chalo wrote:
> >
> > I really doubt measurement has much to do with it. As I've pointed
> > out, early 20th century racers used tires about 1.5" wide on their
> > bikes, thinking that was faster than the alternatives.
>
> The roads were probably a bit rougher back then.
But most racing in those days was on fresh new 'dromes and board
tracks. Those surfaces were not only smoother than today's roads,
they were smoother than most of today's broken-down old velodromes.
Chalo
Nick L Plate
>
> I really think you're underestimating the effort people go to to work such
> things out. There are people out there spending a lot of time with wind
> tunnels etc trying to squeeze seconds for races. It's more pertinent for
> stuff against the clock (TTs, pursuits, etc), but that's quite strong over
> here.
>
> Sure, the superstitious mentality you're describing exists, but at the very
> top level it is backed up by actual research.
No matter what research is done, it really is dow to the individual
rider, who may perform better on a wider tyre, wether perceived or
actual. I suspect the return to wider tyres has been due to the
availability of rims. Deep stiff rims mean the tyre has to work more
in minimising shock and maintaining grip. Late 80's - Only the
incorrect labeling of tyres by Specialized did I use tyres less than
23mm(actual 21mm-label 25) good tyre but still overtly narrow which
encouraged slipout. High pressure to avoid pinch flats means a
shorter contact patch. I had no choice in pressure, they had to be at
120psi, this was also a bit juddery at times and felt inefficient over
rough ground.
Pete Biggs
>
> The faster the hammer hits the nail, the deeper the nail goes into the
> wood.
>
> More rim protection is needed at higher speeds because impact roughly
> corresponds to kinetic energy, which is half the mass times the square
> of the velocity--it rises even faster than the speed.
>
> At 20 mph, a rider hits a chunk of gravel (oops!) with an impact of
> 20^2 whomps, or 400 whomps.
>
> At 25 mph, the same rider hits the same chunk of gravel at 25^2
> whomps, or 625 whomps.
>
> At 30 mph, he hits it at 30^2 whomps, or 900 whomps, more than twice
> as hard.
>
> more pinch flats on bicycles.
I'm not going to care about the tyre if I hit something at 30 mph that's bad
enough to cause a pinch flat to a properly inflated tyre, because I'll be
lying in the road worying about my broken bones.
"Properly inflated" for me means hard enough to survive anything at 20
(maybe 25) mph. In fact I've never had a pinch flat with anything other
than a very soft tyre, despite running into square-edged holes that were
deep enough to bend the wheels, send the bike flying one way and me the
other. The tyres and tubes were fine.
~PB
Pete Biggs
> I'm not going to care about the tyre if I hit something at 30 mph
> that's bad enough to cause a pinch flat to a properly inflated tyre,
> because I'll be lying in the road worying about my broken bones.
>
> "Properly inflated" for me means hard enough to survive anything at 20
> (maybe 25) mph. In fact I've never had a pinch flat with anything
> other than a very soft tyre, despite running into square-edged holes
> that were deep enough to bend the wheels, send the bike flying one
> way and me the other. The tyres and tubes were fine.
ps. That includes 23mm tyres.
> ~PB
Michael Press
<9c71b400-7687-4de7...@r15g2000prd.googlegroups.com>,
Chalo <chalo....@gmail.com> wrote:
> John Forrest Tomlinson wrote:
> >
> > Chalo wrote:
> > >
> > > JFT wrote:
> > >>
> > >> And more to the point, do people trying to go fast care about a little
> > >> extra shock absorbtion?
> > >
> > >Why wouldn't they? Every watt of muscle power they spend absorbing
> > >bumps is a watt that doesn't make them go any faster.
> > >
> > >http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm
> > >http://davesbikeblog.squarespace.com/storage/Speed04.jpg
> > >http://www.fredrompelberg.com/upload/algemeen/Wereldrecord_fiets.JPG
> >
> > Interesting. And all the bike racers who do well around the world on
> > fairly narrow tires are choosing the wrong equipment I suppose?
>
> How would one know whether they were using the optimum size? When was
> the last time a pro road racer used 700x28s other than on
> cobblestones?
>
> Major Taylor used roughly 1.5" (38mm) tires. and he was racing on
> highly groomed 'dromes and board tracks. I reckon he wanted to win
> races too.
Tire losses are in flexing the sidewall and flexing the tread.
Thinner side walls dissipate less energy flexing.
Same for tread. But a wider tire cannot have a sidewall as
thin as a narrower tire because of the way the forces work.
Therefore wider tires have thicker casing and dissipate more
energy flexing. The sweet spot for low rolling resistance
is around 21-25 mm width tires.
I see the experiment every day. Rolling along our streets,
stop pedaling and continue to gain on other bicycles with
wide tires.
--
Michael Press
Ryan Cousineau
carl...@comcast.net wrote:
Well, there was a brief trend of using 650c wheels (and also "funny
bikes" with mismatched-size wheels). The theory that the smaller wheels
meant a lower frontal area didn't work out in the wind tunnel, and funny
bikes were banned (UCI rules say the wheels have to be the same size).
Today, all pros (and, I think, all pro Triathletes) use 700c wheels for
road and TTing, excepting only a few very short riders who might be
using 650c.
Chalo
>
> Tire losses are in flexing the sidewall and flexing the tread.
> Thinner side walls dissipate less energy flexing.
> Same for tread. But a wider tire cannot have a sidewall as
> thin as a narrower tire because of the way the forces work.
> Therefore wider tires have thicker casing and dissipate more
> energy flexing.
Don't think so. Fatter tires have to distort much less to establish a
given contact patch. Even if there is less rubber being worked in a
narrow tire, it is being worked to a much higher degree of
deflection. This accounts for the roller tests Jobst Brandt has
posted many times which show that wider tires of equal construction
exhibit lower rolling resistance than narrower ones.
> The sweet spot for low rolling resistance
> is around 21-25 mm width tires.
That's entirely dependent upon load and surface quality. Just like a
suspended vehicle can maintain a higher speed than an unsuspended
vehicle past a certain function of surface roughness and speed, a
wider, softer tire can be faster when surface quality is taken into
account. Were that not the case, MTB racers could use 1.5" tires or
even road bike tires. But in fact they would not be competitive if
they did so.
> I see the experiment every day. Rolling along our streets,
> stop pedaling and continue to gain on other bicycles with
> wide tires.
I do that on 700x60 tires, merely on the basis of my superior
mass:frontal area ratio and the fact that my bike is in good running
condition. It's the same whether I'm running 700x32 Paselas or 700x60
Big Apples.
Chalo
John Forrest Tomlinson
Dear er,
John Forrest Tomlinson
wrote:
>In the era of 19mm tires, it was an experiment that was down to a lack
>of evidence. I don't know how fast the trickle of information was, but
>it appears at some point tires evolved back to the 23mm range of today.
>As much as anything, that may speak to the subtlety of the advantages.
Yes - excellent point..
John Forrest Tomlinson
If the tests don't exist or can't exist, then you should be looking at
practice by the people who succeed in the endeavour, rather than the
ideas of some slow guy who like to use examples from the 1920 to talk
about racing equipment, or some huge guy who weighs more than twice
what a lot of good bike racers do.
John Forrest Tomlinson
>On Jan 30, 6:39 am, John Forrest Tomlinson <usenetrem...@jt10000.com>
>wrote:
>> On Fri, 30 Jan 2009 00:46:50 -0700, carlfo...@comcast.net wrote:
>> >Unfortunately, citing racers' equipment is a double-edged sword.
>>
>> >All too often, we have no real evidence whether they won because or in
>> >spite of their equipment.
>>
>> Yes, so far better to rely on the clear thinking ideas of a person who
>> as far as we know has zero practical experience in bike racing as a
>> rider, coach, mechanic, or any other capacity such as Carl Fogel.
>
>And how many of the bikes or equipment used by Armstrong was designed
>by a professional bike racer or director? None. It was designed by
>engineers who likely know how to ride a bike assigned to the job by
>Trek or some other company. Having specific experience is
>unnecessary. How many Nascar cars or Goodyear tires are designed by
>people who have driven at 200 mph on 45 degree banked tracks? None.
>Where do you get this idea that a person needs specific experience to
>make something? Oppenheimer was not a pilot or soldier so he should
>not have been able or qualified to make an atomic bomb.
>
They have practical experience of working in the milieu. They do not
leave grad school having studied airplane wind design and make
recommendation that are valid in bikes from the start. Rather they
work with the competitors, looking at the actual situations and
practices and seeing how they can be improved.
That is practical experience.
Carl Fogel and some engineers in this group do not understand the
demands or issues in bike racing, and w/o understanding the issues
facing the product being studied, even a good engineer will often be
off-base.
John Forrest Tomlinson
>
>Dear John,
>
>Ah, your usual signal that you have no argument!
Dear Carl,
As usual you are a coward who refuses to answer relevant questions
about himself.
John Forrest Tomlinson
wrote:
>I've raced. I've driven mechanical support vehicles in races. As a
>neutral support vehicle mechanic, I've changed a wheel for a racer
>(badly). I've won races, albeit pointless amateur low-cat ones. I've
>done all the mechanical work on all my racing bicycles. I've ridden
>road, crits, TTs, track (not in competition yet), cyclocross, mountain
>bikes, and if it wasn't for the narrow-mindedness of the local racing
>association, would have raced cyclocross on a tandem. I've built up a
>Giant TCR 0 from a frame and a bunch of boxes of Dura-Ace parts. Are my
>bona fides sufficient?
>
>I agree with Carl's claim that "all too often, we have no real evidence
>whether [racers] won because or in spite of their equipment."
>
>Any questions?
Yes -- one:
So who do you think is more likely to be right about tire choice for
racing: you who've used tires in races, looked closely at other tires
that successful racers use, or Carl?
Ryan Cousineau
John Forrest Tomlinson <usenet...@jt10000.com> wrote:
Carl, in my opinion, has thought about this question as carefully as
most bike racers. He has thought about it at least as carefully as I
have. I would say that my opinions about tire choices in races are first
informed by price (no seriously, I get a really good local deal on Kenda
Kaliente 23mm clinchers, so I use those), and the opinion I give to
those who ask me is to not worry much about tires, and probably to run
at least a 23.
So Carl's advice is as good as mine.
More to the point, Carl is right: there's a lot of equipment choices in
bike racing that are either hard to analyze, or hard to defend.
Don't get me started on cellar tire aging, and yet that's something the
Discovery/Postal mechanics were very keen on. It probably didn't hurt or
help,
carl...@comcast.net
Dear Pete,
What do you think causes all those flat in Paris-Roubaix?
Cheers,
Carl Fogel
Ryan Cousineau
Phil W Lee <phil(at)lee-family(dot)me(dot)uk> wrote:
> Ryan Cousineau <rcou...@gmail.com> considered Sat, 31 Jan 2009
> I'd understood that the wind tunnel confirmed that they DID give an
> advantage, and that was why UCI banned them. Rumour was they didn't
> fancy the thought that someone might just embarass the rest of the
> peloton in a major event riding a "funny looking bike".
> Not much risk of that if it doesn't actually have any advantage, so
> UCI obviously beleived it did - they would have more than happy to see
> funny looking bikes coming in last, but it just wasn't going to
> happen.
The UCI banned mismatched wheel sizes (don't ask me why), but two 650c
wheels are just fine. It's possible a funny bike (650c up front only)
would give an aero advantage where a bike with two 650c wheels wouldn't,
but it's not obvious how. Nonetheless, there were riders in both
Triathlons and TTs who for a time used 650c wheels, and it was not the
rules that made them stop.
The relevant regulations are these two:
1.3.006
The bicycle is a vehicle with two wheels of equal diameter. The front
wheel shall be steerable; the rear wheel shall be driven through a
system comprising pedals and a chain.
1.3.018
Wheels of the bicycle may vary in diameter between 70 cm maximum and 55
cm minimum, including the tyre. [it goes on, but is not relevant here]
The whole of the UCI's sporting regulations are here:
<http://www.uci.ch/templates/UCI/UCI2/layout.asp?MenuId=MTkzNg>
Part I, "General Organization of Cycling as a Sport" is the document rbt
types interested in racing should pay attention to: Chapter 3, sections
1 & 2 deal with the rules about the design of the bicycle. Most
entertaining reading, and note that these sections are far more detailed
than they were in, oh, 1980.
<http://www.uci.ch/includes/asp/getTarget.asp?type=FILE&id=34033>
82-page PDF.
650c wheels are ISO 571; well within the minimum diameter. On the top
end, a 27" wheel (ISO 630) would definitely be okay, and even a 700B
(ISO 635) might work.
> So it doesn't really pay to do real research - you could spend a
> fortune doing it and they'd just ban the fruits of it anyway.
> > and funny
> >bikes were banned (UCI rules say the wheels have to be the same size).
> >
> >Today, all pros (and, I think, all pro Triathletes) use 700c wheels for
> >road and TTing, excepting only a few very short riders who might be
> >using 650c.
The major result of the 650c fad is that nowadays, the best way to get a
decent TT bike on the cheap is to look for a triathlete desperate to
dump their 650c rig. If you're on the tall side, this will result in a
very funny-looking bike, but it should be legal.
Frank Krygowski
wrote:
> On Fri, 30 Jan 2009 07:04:38 -0800 (PST), "russellseat...@yahoo.com"
>
>
>
> <russellseat...@yahoo.com> wrote:
> >On Jan 30, 6:39 am, John Forrest Tomlinson <usenetrem...@jt10000.com>
> >wrote:
> >> On Fri, 30 Jan 2009 00:46:50 -0700, carlfo...@comcast.net wrote:
> >> >Unfortunately, citing racers' equipment is a double-edged sword.
>
> >> >All too often, we have no real evidence whether they won because or in
> >> >spite of their equipment.
>
> >> Yes, so far better to rely on the clear thinking ideas of a person who
> >> as far as we know has zero practical experience in bike racing as a
> >> rider, coach, mechanic, or any other capacity such as Carl Fogel.
>
> >And how many of the bikes or equipment used by Armstrong was designed
> >by a professional bike racer or director? None. It was designed by
> >engineers who likely know how to ride a bike assigned to the job by
> >Trek or some other company. Having specific experience is
> >unnecessary. How many Nascar cars or Goodyear tires are designed by
> >people who have driven at 200 mph on 45 degree banked tracks? None.
> >Where do you get this idea that a person needs specific experience to
> >make something? Oppenheimer was not a pilot or soldier so he should
> >not have been able or qualified to make an atomic bomb.
>
> They have practical experience of working in the milieu. They do not
> leave grad school having studied airplane wind design and make
> recommendation that are valid in bikes from the start. Rather they
> work with the competitors, looking at the actual situations and
> practices and seeing how they can be improved.
Do you seriously think all the engineers who post to r.b.tech just
graduated and know more about wing design than about bicycles?
> Carl Fogel and some engineers in this group do not understand the
> demands or issues in bike racing, and w/o understanding the issues
> facing the product being studied, even a good engineer will often be
> off-base.
You've repeatedly claimed that those disagreeing with you on these
matters "don't understand the issues in racing." Since some of us
have raced, I don't quite believe that, but - why not take the time to
explain "the issues"?
- Frank Krygowski
carl...@comcast.net
wrote:
[snip]
>1.3.006
>The bicycle is a vehicle with two wheels of equal diameter. The front
>wheel shall be steerable; the rear wheel shall be driven through a
>system comprising pedals and a chain.
>
>1.3.018
>Wheels of the bicycle may vary in diameter between 70 cm maximum and 55
>cm minimum, including the tyre. [it goes on, but is not relevant here]
>
>The whole of the UCI's sporting regulations are here:
>
><http://www.uci.ch/templates/UCI/UCI2/layout.asp?MenuId=MTkzNg>
[snip]
Dear Ryan,
Illegal! The chain drive doesn't matter--the wheels are not of equal
diameter and they're also over 70 cm, even without the tire:
http://www.rover-v8.nl/dutchroverarchives/fiets/safety/007.jpg
(Its left-hand drive should also probably be illegal.)
Illegal! No damned shaft drives allowed!
http://www.majortaylor.com/page40.html
Illegal! Different size wheels, wheel too big, treadle drive:
http://www.copakeauction.com/bicycles/2003-bicycles/003a.jpg
No, no, no! Two chains won't make it legal--they're on the front, the
wheels are different sizes, and the front wheel is too damned big!
http://www.jimlangley.net/ride/kangaroo.htm
Thank heavens the UCI has conducted research to determine the proper
kind of bicycle, sparing us such horrors.
These two, however, are presumably legal, since they use a chain and
pedal drive and have wheels of the same size, well within the limits:
http://i9.tinypic.com/4taqys4.jpg
http://www.automag.be/IMG/jpg/Levocyclette.jpg
Cheers,
Carl Fogel
Ryan Cousineau
carl...@comcast.net wrote:
> On Sat, 31 Jan 2009 04:37:10 GMT, Ryan Cousineau <rcou...@gmail.com>
> wrote:
>
> [snip]
>
> >1.3.006
> >The bicycle is a vehicle with two wheels of equal diameter. The front
> >wheel shall be steerable; the rear wheel shall be driven through a
> >system comprising pedals and a chain.
> >
> >1.3.018
> >Wheels of the bicycle may vary in diameter between 70 cm maximum and 55
> >cm minimum, including the tyre. [it goes on, but is not relevant here]
> >
> >The whole of the UCI's sporting regulations are here:
> >
> ><http://www.uci.ch/templates/UCI/UCI2/layout.asp?MenuId=MTkzNg>
>
> [snip]
>
> Dear Ryan,
>
> Illegal! The chain drive doesn't matter--the wheels are not of equal
> diameter and they're also over 70 cm, even without the tire:
> http://www.rover-v8.nl/dutchroverarchives/fiets/safety/007.jpg
> Thank heavens the UCI has conducted research to determine the proper
> kind of bicycle, sparing us such horrors.
>
> These two, however, are presumably legal, since they use a chain and
> pedal drive and have wheels of the same size, well within the limits:
> http://i9.tinypic.com/4taqys4.jpg
> http://www.automag.be/IMG/jpg/Levocyclette.jpg
Dear Carl: shows what you know about racing!
The Levocyclette is likley to fall afoul of the "in a circular motion"
regulation:
1.3.010
The bicycle shall be propelled solely, through a chainset, by the legs
(inferior muscular chain) moving in a circular movement, without
electric or other assistance.
I'll never let you fix my bike again.
carl...@comcast.net
wrote:
Dear Ryan,
That sounds like a circular argument.
Cheers,
Carl Fogel
Ben C
Interesting. It may be that they figured out the wider tyres gave them
lower rolling resistance but didn't account for their extra aero drag
(which is harder to measure).
Or maybe it was just old wives' tales, or a bit of both.
dusto...@mac.com
> I really doubt measurement has much to do with it. As I've pointed
> out, early 20th century racers used tires about 1.5" wide on their
> bikes, thinking that was faster than the alternatives.
Tire construction, materials and technology, were not nearly as good
as in recent times. Notice multiple spare tires being carried on old
autos; my grandmother told me they'd usually have at least one flat
per excursion. Of course roads (speaking of the 20's) were not the
equal of the good roads of more recent times.
> Twenty years
> ago, many racers were using 19s and 20s on their bikes, thinking that
> was faster. Now they're using 23s, thinking that's faster.
>
> Is every such fashion change for the faster? How could it be? But
> that's the nature of fashion-- as long as everybody adopts it, then
> you never have to know one way or the other.
I think the "too many flats" equation was finally solved <g>.
> I'm sure that if Lance
> in his heyday had used 700x18s and won on them, everybody else would
> have switched to those. And if he'd used 700x32s and won on them,
> everybody would have switched to those.
Flip side, Lance didn't "switch", probably for good reason.
IMHO it goes to flats-- you use the smallest (lightest, most aero)
tire you can that doesn't "flat too often".
Note the handling problems seen on the TT bikes, where they're using
small-section tires pumped hard. That tells you something about
"priorities", which may have a basis in wind tunnel testing-- and
probably does with LanceCo.
> Thus we'll never really know whether a high quality race tire built
> in 28mm or 32mm casing width would be as fast in races as 23mm or 25mm
> tires.
You have a tire bias, Chalo!
--D-y
andre...@aol.com
wrote:
> On Fri, 30 Jan 2009 14:28:19 -0700, carlfo...@comcast.net wrote:
> >On Fri, 30 Jan 2009 19:49:09 -0000, "Clive George"
> ><cl...@xxxx-x.fsnet.co.uk> wrote:
>
Or, simply try stuff and see if you notice a difference. I have some
michelin dynamic tires. They are fat and heavy. I used them for a
while and couldn't tell much difference riding in groups. But, they
looked fat and slow. So, I replaced them with thinner lighter tires.
Don't know if it makes a difference but psychologically I think that
it may. Yet, other things, that don't affect me psychologically that
much. My bike is heavier and older than most and I don't feel that I
am at a disadvantage. Yet, the tires gave me the impression that I had
a disadvantage. Silly, ain't it.
Try lightweight 23 mm tires and see how you like them. They'll wear
out eventually. If you don't get flats and you feel good, keep using
the, Otherwise go to a heavier, wider tire.
If you want cheap lightweight tires to experiment with, go to
probikekit.com. You can get Michelin Lithyon for very little. Im close
to 200lbs and have ridden michelin 23 mm for a long time and like
them. They last a reasonable long time. But, I'll ride them until you
can see through them.
A Muzi
>>>>> in 28mm or 32mm casing width would be as fast in races as 23mm or 25mm
>>>>> tires. If anyone demonstrates racing success with an unorthodox tire
>>>>> size-- whether or not that success is related to the tires-- the
>>>>> entire population of racers will switch to the novel size.
>>> "Clive George" <cl...@xxxx-x.fsnet.co.uk> wrote:
>>>> I really think you're underestimating the effort people go to to work such
>>>> things out. There are people out there spending a lot of time with wind
>>>> tunnels etc trying to squeeze seconds for races. It's more pertinent for
>>>> stuff against the clock (TTs, pursuits, etc), but that's quite strong over
>>>> here.
>>>> Sure, the superstitious mentality you're describing exists, but at the very
>>>> top level it is backed up by actual research.
>> carlfo...@comcast.net wrote:
>>> I'm inclined to agree with you . . .
>>> But then I ask myself where the actual research is?
>>> That is, do you have any links to actual research that shows that an
>>> actual rider on a reasonably normal road course is measurably faster
>>> on 20, 23, or 25 mm tires?
>>> I mean actual results for a real rider over an hour or more on a road
>>> surface, to overcome the many complications of road surface versus
>>> smooth drum, wider tire wind drag, frame size affecting aerodynamics,
>>> tire pressure, rider fatigue, and so on.
>>> The more I think about it, the more that I wonder if there are no such
>>> tests. The kinds of differences predicted by isolated theory and
>>> laboratory tests might well be lost in the noise.
> John Forrest Tomlinson <usenetrem...@jt10000.com>wrote:
>> If the tests don't exist or can't exist, then you should be looking at
>> practice by the people who succeed in the endeavour, rather than the
>> ideas of some slow guy who like to use examples from the 1920 to talk
>> about racing equipment, or some huge guy who weighs more than twice
>> what a lot of good bike racers do.
andre...@aol.com wrote:
> Or, simply try stuff and see if you notice a difference. I have some
> michelin dynamic tires. They are fat and heavy. I used them for a
> while and couldn't tell much difference riding in groups. But, they
> looked fat and slow. So, I replaced them with thinner lighter tires.
> Don't know if it makes a difference but psychologically I think that
> it may. Yet, other things, that don't affect me psychologically that
> much. My bike is heavier and older than most and I don't feel that I
> am at a disadvantage. Yet, the tires gave me the impression that I had
> a disadvantage. Silly, ain't it.
>
> Try lightweight 23 mm tires and see how you like them. They'll wear
> out eventually. If you don't get flats and you feel good, keep using
> the, Otherwise go to a heavier, wider tire.
>
> If you want cheap lightweight tires to experiment with, go to
> probikekit.com. You can get Michelin Lithyon for very little. Im close
> to 200lbs and have ridden michelin 23 mm for a long time and like
> them. They last a reasonable long time. But, I'll ride them until you
> can see through them.
If you want to pursue that, try successive rides on a coarse fabric
Michelin Dynamic 23 and then a more supple 25mm Michelin Pro with finer
fabric. Or even a 28mm Pasela. Tire casing material, tread thickness and
compound matter; not just width.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
Pete Biggs
>>> I'm not going to care about the tyre if I hit something at 30 mph
>>> that's bad enough to cause a pinch flat to a properly inflated tyre,
>>> because I'll be lying in the road worying about my broken bones.
>>>
>>> "Properly inflated" for me means hard enough to survive anything at
>>> 20 (maybe 25) mph. In fact I've never had a pinch flat with
>>> anything other than a very soft tyre, despite running into
>>> square-edged holes that were deep enough to bend the wheels, send
>>> the bike flying one way and me the other. The tyres and tubes were
>>> fine.
>>
>> ps. That includes 23mm tyres.
> What do you think causes all those flat in Paris-Roubaix?
Pinch flats at 20 mph? Something wrong with their wheels? Or slow ordinary
punctures that lowered the pressure to make them soft enough to pinch-flat.
That's a common cause of pinch flats.
Those cobbles are nothing compared the potholes I've run into that bent my
wheels and sent me flying off the bike.
~PB
Chalo
I wonder. As for possible technical reasons, maybe the rubber tread
compounds then available weren't wear-resistant enough to cope with
the specific loading of a narrow tire, or the casings weren't reliable
under the pressures required for narrow tires. Perhaps glues were not
up to the job, or not considered to be up to the job of holding a
narrow tire on under racing loads.
Cycle racing was a big money sport back then (1890s-1920s), and if
anyone had thought that narrower tires would give them a winning
advantage, I'm sure they'd have tried them.
Chalo
Pete Biggs
> carl...@comcast.net wrote:
>
>>>> I'm not going to care about the tyre if I hit something at 30 mph
>>>> that's bad enough to cause a pinch flat to a properly inflated
>>>> tyre, because I'll be lying in the road worying about my broken
>>>> bones. "Properly inflated" for me means hard enough to survive anything
>>>> at
>>>> 20 (maybe 25) mph. In fact I've never had a pinch flat with
>>>> anything other than a very soft tyre, despite running into
>>>> square-edged holes that were deep enough to bend the wheels, send
>>>> the bike flying one way and me the other. The tyres and tubes were
>>>> fine.
>>>
>>> ps. That includes 23mm tyres.
>
>> What do you think causes all those flat in Paris-Roubaix?
>
> Pinch flats at 20 mph?
Or 30+
> Something wrong with their wheels? Or slow
> ordinary punctures that lowered the pressure to make them soft enough
> to pinch-flat. That's a common cause of pinch flats.
And the most likely cause, I think.
carl...@comcast.net
Dear Pete,
What do you think is "wrong" with the wheels of dozens of pro racers
in Paris-Roubaix?
And what do you think would cause all your hypothetical slow leaks in
a one-day professional race over cobblestones that you believe nothing
compared to what you hit?
Cheers,
Carl Fogel
Chalo
>
> Chalo wote:
> >
> > As I've pointed
> > out, early 20th century racers used tires about 1.5" wide on their
> > bikes, thinking that was faster than the alternatives.
>
> equal of the good roads of more recent times.
But the velodromes and tracks where most racing took place were
smoother than today's roads and most of today's 'dromes.
> IMHO it goes to flats-- you use the smallest (lightest, most aero)
> tire you can that doesn't "flat too often".
> Note the handling problems seen on the TT bikes, where they're using
> small-section tires pumped hard. That tells you something about
> "priorities", which may have a basis in wind tunnel testing-- and
> probably does with LanceCo.
There has been a whole lot less effort expended in fairing the tire to
the rim than I would expect. A tire-rim system with the shape and
width of both parts controlled to give an aerodynamically efficient
shape would yield much better results than just making the tire
smaller. Deep section rims are a move in that direction, but rims
that combine with the tire to make a streamlined unit would be much
better-- and they wouldn't have to be silly narrow either.
> > Thus we'll never really know whether a high quality race tire built
> > in 28mm or 32mm casing width would be as fast in races as 23mm or 25mm
> > tires.
>
> You have a tire bias, Chalo!
I have a bias informed by riding for many years on tires from about
21mm to 75mm wide, and observing their relative merits and drawbacks.
I like big fat tires (meaning 50mm+), but I know that they are not the
fastest or most efficient way to go. I have used really skinny tires
extensively in the past, but I know from hard-won experience that they
are neither reliable nor faster than the slightly wider
alternatives.
I find my own personal sweet spot for speed and tire reliability in
the 35-40mm range of tire width. I don't assume this would be the
same for other riders. However, I have spent a lot of time with the
urban cycling community in both Seattle and Austin, and I have seen
again and again young messengers and self-styled sport riders come to
the realization that 28mm tires are no slower than narrower ones, but
are way better at getting you there with air still in the tires and
wheels intact. I don't think this is mere coincidence. I do think
that they often stop at 28mm because so many of their bikes can't
accept a fatter tire than that.
Chalo
Carl Sundquist
> Ryan Cousineau <rcou...@gmail.com> considered Sat, 31 Jan 2009
> 00:40:19 GMT the perfect time to write:
>
>> In article <87r6o4h09r5thq0a3...@4ax.com>,
>>
>>> On Fri, 30 Jan 2009 19:49:09 -0000, "Clive George"
>>> <cl...@xxxx-x.fsnet.co.uk> wrote:
>>>
>>>> news:12afe23d-acf6-470a...@o40g2000prn.googlegroups.com...
>>>>
>>>>> Thus we'll never really know whether a high quality race tire built
>>>>> in 28mm or 32mm casing width would be as fast in races as 23mm or 25mm
>>>>> size-- whether or not that success is related to the tires-- the
>>>>> entire population of racers will switch to the novel size.
>>>> things out. There are people out there spending a lot of time with wind
>>>> tunnels etc trying to squeeze seconds for races. It's more pertinent for
>>>> stuff against the clock (TTs, pursuits, etc), but that's quite strong over
>>>> here.
>>>>
>>>> Sure, the superstitious mentality you're describing exists, but at the very
>>>> top level it is backed up by actual research.
>>>
>>> I'm inclined to agree with you . . .
>>>
>>> But then I ask myself where the actual research is?
>>>
>>> That is, do you have any links to actual research that shows that an
>>> actual rider on a reasonably normal road course is measurably faster
>>> on 20, 23, or 25 mm tires?
>>>
>>> I mean actual results for a real rider over an hour or more on a road
>>> surface, to overcome the many complications of road surface versus
>>> smooth drum, wider tire wind drag, frame size affecting aerodynamics,
>>> tire pressure, rider fatigue, and so on.
>>>
>>> The more I think about it, the more that I wonder if there are no such
>>> tests. The kinds of differences predicted by isolated theory and
>>> laboratory tests might well be lost in the noise.
>>>
>>> are actually used in the TDF. And the riders, who tend to stay in the
>>> same pack most days, use a wide variety of tires (often re-badged to
>>> suit their preferences), despite any lab test results indicating which
>>> one has the best theoretical rolling resistance.
>>>
>>> Come to think of it, is there a lot of research that shows that 700c
>>> tires, front and rear, are the very best height for speed on
>>> traditional road bicycles?
>> Well, there was a brief trend of using 650c wheels (and also "funny
>> bikes" with mismatched-size wheels). The theory that the smaller wheels
>> meant a lower frontal area didn't work out in the wind tunnel,
>
> I'd understood that the wind tunnel confirmed that they DID give an
> advantage, and that was why UCI banned them. Rumour was they didn't
> fancy the thought that someone might just embarass the rest of the
> peloton in a major event riding a "funny looking bike".
> Not much risk of that if it doesn't actually have any advantage, so
> UCI obviously beleived it did - they would have more than happy to see
> funny looking bikes coming in last, but it just wasn't going to
> happen.
I don't think the UCI banned Steve Bauer's 1993 bike. They don't get
much more ridiculous than that. Unfortunately I can't find a link on the
web.
Dan O
> Is there any real difference between 23mm and 25mm tires as far as
> speed. Will 2mm make you that slower or faster?
Not significantly - that's for sure.
To give the absolute simpleton perspective, when I was a kid, riding
20 x 1.75 tires, I found that higher pressure resulted in lower
rolling resistance and faster acceleration with less effort. I note
that narrower tires generally have higher max pressure ratings.
I run 28's on the bike I ride most. These tires are not a speed
constraint for me. There's room for at least 32's, I think, and will
probably try some eventually.
I believe that between tires that close in size, materials and
construction, including maybe esp the casing, are more important to
how tires ride.
I have 23's on my go-fast bike. They make the bike look really racy,
and the bike does go fast. I wouldn't want to ride on anything
smaller, and may very well get some 25's when I replace them.
carl...@comcast.net
Dear Chalo,
Highwheeler racers after 1885 used solid tires as narrow as 5/8" (~16
mm) on the front and 1/4" (~6 mm) on the rear:
http://americanhistory.si.edu/ONTHEMOVE/collection/object_289.html
In general, highwheelers used wider 1" (~25 mm) solid front tires.
Rolling resistance is a bit different for solid tire that's over 50
inches high. The softer the solid rubber, the more it squashes, and
the greater the drag--but the improved suspension may offset the loss
of power.
Given the same kind of solid rubber, the narrower solid tire may well
be worse in tire drag than wide solid tire. Since there's no
air-pressure to vary, both tires need roughly the same contact area to
support the weight--you can't "pump" a narrow solid tire up to get a
smaller contact patch. So the narrow solid tire ends up with a longer,
narrow contact patch than the wide solid tire, which is less
efficient, judging by studies of modern pneumatic tires, which show
that the shorter, more circular contact patch loses less energy.
However, the thinner solid highwheeler tire had an obvious attraction
that's missing from modern tires: weight.
With modern tires, we need extraordinarily accurate scales to tell the
difference in weight between two similar 700c tires of slightly
different widths. A 23 mm tire might be ~8% lighter than a 25 mm tire
of the same model, 230 grams versus 250 grams.
But a 1" tire on a 55" highwheeler is an inch-wide tube of solid
rubber over fourteen feet long.
pi * (0.5)^2 = 0.7584 inch^2 tire cross-section
55" * 3.141 = ~173 inches tire length
173 * 0.7584 = 131.2 cubic inches of 1" rubber tire
Compared to water, natural rubber has a density of 0.91:
http://www.tfmconsultants.com/Density%20of%20Polymers.html
Water weighs about 0.036 pounds per cubic inch, so natural rubber
weighs about 0.032 pounds per cubic inch:
http://ga.water.usgs.gov/edu/waterproperties.html
131.2 inch^3 rubber * 0.032 lbs/inch^3 = 4.2 lbs of front tire
That means a ~1900 gram front tire on a typical highwheeler, almost
ten times as heavy as a modern ~200 gram racing tire.
Reduce the inch-wide tire to 5/8", and the weight savings are
something that our great grandfathers could feel just by hefting the
tires in their hands:
pi * (5/8 / 2)^2 = ~0.307 inches^2 tire cross-section
55" * 3.141 = ~173 inches tire length
173 * 0.307 = 53.1 cubic inches of 5/8" rubber tire
53.1 inch^3 rubber * 0.032 lbs/inch^3 = 1.7 lbs of front tire
So a 5/8" solid front tire saved about 2.5 lbs, about 1100 grams
lighter than the ordinary 1" tire.
That's the kind of weight difference that you can easily feel--an
ordinary 4.2 lb tire weighed more than twice as much as a 1.7 pound
racing tire.
Admittedly, a 2.5-pound difference wasn't going to make much actual
difference for a 160-lb rider on a 30 to 40-lb highwheeler going in
circles on the level race track where such machines could survive.
But at least it didn't require a set of pharmacy scales to detect the
difference.
Again, the narrow tire may well have been slower, despite its light
weight, because it produced a long, inefficient contact patch.
But the results produced by such differences are so small that they
usually can't be detected in real-world results because they're lost
in the noise.
Incidentally, the early pneumatic tires were so wide and thick that
they rivalled solid 1"x55" 4.2lb highwheeler tires for weight. Here's
a weight table of 1890s Morgan & Wright pneumatic tires by pairs (you
need a pair of pneumatics, but only a single front solid on a
highwheeler):
http://www.blackbirdsf.org/m-w/tires.html
The pneumatic pairs were 3 to 6 pounds of rubber, ~700 to ~1400 grams
per tire. Racing versions, of course, were lighter.
Cheers,
Carl Fogel
carl...@comcast.net
>On Jan 30, 1:21 pm, Chalo <chalo.col...@gmail.com> wrote:
>
>> I really doubt measurement has much to do with it. As I've pointed
>> out, early 20th century racers used tires about 1.5" wide on their
>> bikes, thinking that was faster than the alternatives.
>
>Tire construction, materials and technology, were not nearly as good
>as in recent times. Notice multiple spare tires being carried on old
>autos; my grandmother told me they'd usually have at least one flat
>per excursion. Of course roads (speaking of the 20's) were not the
>equal of the good roads of more recent times.
[snip]
Dear D,
Actually, old bicycle tires were pretty thick and heavy and
flat-resistant. Solid rubber tread is solid rubber tread.
The routine flat tires of the Tour de France even into the 1950s were
partly due to what we would consider dreadful roads, with riders
zooming along dirt roads, hitting gravel and rocks.
The rocks were bad enough, but the real problem was horseshoe nails:
" . . . the Toronto Star sought a history lesson from Dansk Cyklist
Forbund - the Federation of Danish Cyclists - an organization launched
in 1905 when the pressing issue of the day was punctures resulting
from horseshoe nails littered along Copenhagen's network of horse
paths."
http://www.commondreams.org/archive/2008/03/29/7972
Even in the 1950s, roads were littered with nasty nails, often
sticking up from torn-off horseshoes.
Remember all those chunks of semi-trailer tires that you see along the
highway? Torn-off horseshoes and nails were far more common and much
harder to spot and avoid in the dirt.
People left nails, too.
Mixed in with the now-vanished horseshoe nails were all the nails from
the now-vanished hobnailed shoes. People walked a lot more, not for
exercise, but to get places, and they wore shoes full of nails, which
wore out and littered the roads:
"The other Sunday afternoon I rode over on my bicycle to see the
Hobinsons. They live seven miles away. Tomkinb and others were there.
People who live in remote country places always eeem pleased to see a
fellow creature, but Robinson and his wife are unusually hospitable
and good-natured. After I had had some tea, and thought of leaving, a
hobnail was discovered in the tyre of Tomkins's bicycle."
"Punch," 1989
http://books.google.com/books?id=RXJXAAAAMAAJ&printsec=titlepage&dq=hobnails+bicycles+punctures#PRA1-PA46,M1
The famous 1895 x-ray on the right shows the hobnails in the shoes:
http://www.slac.stanford.edu/pubs/beamline/25/2/25-2-linton.pdf
An 1895 comment from the US Consul in Germany about hobnails and
bicycle tires:
"The roads of Europe are strewn with hobnails that fall from the shoes
of peasants, and as amateurs here possess little of the ready
ingenuity of Americans for repairing punctures . . ."
http://books.google.com/books?id=c-0ZAAAAIAAJ&printsec=titlepage#PRA1-PA326,M1
The US was no better, as this Wikipedia comment about pre-1914 Rambler
automobiles emphasizes:
"The interchangeable wheel and a spare tire made travel a lot easier
on primitive roads that were littered with stray horseshoe nails."
http://en.wikipedia.org/wiki/Rambler_(automobile)
A glum British comment on the horseshoe menace:
"Early tyres were canvas tubes with a coating of rubber, by the 1930s
cord was added to the tyre making them rather more robust, but in a
world where horses were still common horseshoe nails on the roads
remained a major source of punctures."
http://www.igg.org.uk/gansg/00-app1/rt-intro.htm
Even the Michelin Man paid homage to the horseshoe enemy:
http://www.bobkestrut.com/images/bibendum1.jpg
http://www.bobkestrut.com/images/bibendum5.jpg
http://www.bobkestrut.com/2006/03/05/just-who-is-that-jolly-puffy-toff/
That's a horseshoe with nails hanging out of the goblet on the
Michelin Man's coat-of-arms.
The other great road hazard that's largely vanished is glass. Yes, RBT
is still full of complaints about glass on the roads, but the aluminum
can and the plastic bottle have reduced the broken glass problem so
much that we should be ashamed of complaining.
Cheers,
Carl Fogel
John Forrest Tomlinson
>Cycle racing was a big money sport back then (1890s-1920s), and if
>anyone had thought that narrower tires would give them a winning
>advantage, I'm sure they'd have tried them.
But now when people use narrower tires they're wrong? They just use
them for what? For fashion? Because they work worse and people like
to suffer? What?
John Forrest Tomlinson
<frkr...@gmail.com> wrote:
>You've repeatedly claimed that those disagreeing with you on these
>matters "don't understand the issues in racing." Since some of us
>have raced, I don't quite believe that, but - why not take the time to
>explain "the issues"?
For example, in an earlier discussion you didn't understand the
importance of drafting almost all the time in mass start bike racing,
saying aerodyanmics only became really important in breaks (and also
in time trials). Some of your comments about that were laughable.
Carl doesn't understand that success and failure in bike racing often
hinges on moments when riders are at their limits, and little effects
are magnified because some riders can stay within their limits and
others can't.
John Forrest Tomlinson
wrote:
>
>Carl, in my opinion, has thought about this question as carefully as
>most bike racers. He has thought about it at least as carefully as I
>have. I would say that my opinions about tire choices in races are first
>informed by price (no seriously, I get a really good local deal on Kenda
>Kaliente 23mm clinchers, so I use those), and the opinion I give to
>those who ask me is to not worry much about tires, and probably to run
>at least a 23.
>
>So Carl's advice is as good as mine.
But his is often wrong.
Pete Biggs
> What do you think is "wrong" with the wheels of dozens of pro racers
> in Paris-Roubaix?
You tell me.
> And what do you think would cause all your hypothetical slow leaks in
> a one-day professional race over cobblestones that you believe nothing
> compared to what you hit?
Stone fragments, perhaps.
Instead of asking me question, it might be more informative if you tell us
exactly what you know about the flats suffered in the Paris-Roubaix. Have
you examined their tyres and wheels?
~PB
carl...@comcast.net
Dear Pete,
You're the one who proposed mysterious "wrong" wheels causing flats in
Paris-Roubaix, not me. It's up to you to tell us what's wrong with
them--I have no idea what you're thinking.
The same thing is true of the mysterious "slow leaks" that you propse
to explain the well-known impact flats that plague Paris-Roubaix every
year in the cobblestone sections.
But since you're asking for help, I'll give you what I can. I was
surprised, too, when I learned that some impacts can damage a rim
without causing an impact puncture (and vice-versa).
What happens depends roughly on how broad the impact area is--you can
spread enough force out over a rim to damage it splitting the inner
tube. Speed, inflation, rim brand, rider weight, and so on make it
well-nigh impossible to predict what will happen with any given
pothole, crack, or chunk of gravel.
As for what I know about Paris-Roubaix, it's not unheard of for RBT
posters to post bizarre theories that hitting the cobblestones is
somehow not the cause of the swarms of flats, ruined wheels, and
crashes, decade after decade.
So far, you've suggested that most of the wheels used in Paris-Roubaix
over the last century must somehow be "wrong" and that "perhaps" stone
fragments are causing slow leaks.
Cheers,
Carl Fogel
Ryan Cousineau
Phil W Lee <phil(at)lee-family(dot)me(dot)uk> wrote:
> Ryan Cousineau <rcou...@gmail.com> considered Sat, 31 Jan 2009
> So what did the rules say before they changed them, and when was it?
> Why do YOU think they changed them?
I don't know. But I have a general idea that the rules have become
stricter on what qualifies for competition. Notable rule changes in the
last decade or two would have been the same-wheel rule and the bike
frame rules that outlawed, for example, the Trek Y-Foil.
> I say a bicycle is still a bicycle, no matter what UCI says, but that
> they are stifling development and innovation.
>
> I dispute their authority to decide what qualifies for record
> attempts. I wouldn't mind if they'd be honest and describe them as
> the upright traditional records, but they claim an authority over the
> English language that they have no right to.
> Eventualy, the UCI record will end up as irrelevant as the ordinary
> one, and their races will have to be advertised as "traditional
> upright" races, in the same way as anyone wanting to arrange ordinary
> racing has to make it clear that entry is restricted to "penny
> farthings".
"Athlete's Hour" or "Best Hour Performance" is the title. The IHPVA is
content to sanction the records you care about, and the UCI has never
tried to stop them.
> The BICYCLE records have been held for years by streamlined
> recumbents.
> And since this is rec.bicycles.tech not rec.uciracing.tech, I don't
> see any reason to exclude perfectly good bicycles just because the UCI
> don't like them.
Re-read that rulebook, and you'll see that the UCI sees the spirit of
the sport as being a contest between athletes on roughly equal
equipment. Yes, their rules about what constitutes a bicycle are narrow,
but they lead to riders riding bicycles that look...
> And no, I don't ride a 'bent, both my wheels are the same size, and my
> frame is 531ST :)
...remarkably like the bike you ride.
If the UCI has resisted certain innovations, it's for two reasons: the
first is a fear that pro cycling would devolve into a technological arms
race of narrow-purpose and goofy bicycles, stuff that would be all but
unrideable except in competition: envision the Varna Diablo II* reshaped
just enough to corner effectively and let the rider breathe.
Given that, the UCI has chosen to force a frame that ends up looking
like almost all the non-racing bikes in the world. It's a practical
layout. The result is that even today, you could hand an average cyclist
a pro peloton bike in their size, and they could ride it to the corner
grocery or halfway across France.
As for the best machine, well, the IHPVA sanctions those races ably, and
everyone seems content with the arrangement.
The analogy might be to the difference between touring car racing and
formula 1, except that all the best racers are in touring cars, so to
speak.
Win on Sunday, sell on Monday,
*A machine which I admire tremendously. It was built about 100 km from
my house, and the record-holding pilot (Whittingham) is a local
framebuilder: <http://www.evertibikes.com/overview.htm>
His line-up is all conventional-frame bikes.
carl...@comcast.net
Dear John,
As always, it's your imagination and over-sensitive reaction, not my
lack of understanding.
But keep on ranting that victory depends on details likely to be lost
in the noise or even mistaken--the law of averages suggests that
you'll have to be right occasionally, and the challenge for the rest
of us is to make sure that we don't just dismiss you automatically.
Cheers,
Carl Fogel
Chalo
Because they _think_ that's the fastest option. Instrumented rollers
suggest that a wider tire than racers use would be faster. The wind
tunnel suggests that lenticular disc wheels with knife edges would be
faster.
My point is that the fastest bike riders around used to agree that
40mm tires were the best, then later they agreed that 19mm tires were
best, and now it's something else. Were they all correct? If they
weren't all correct, why should we believe that it's racers who use
23mm tires who have it right?
Chalo