Wide Tire Testing
littlecirclesvt.com :: mike beganyi
apparently being tested in Finland:
http://www.cyclingnews.com/features/tech-feature-the-work-of-wheel-energy
Wider is faster...
They also test against a variety of surfaces, and do puncture tests.
Interesting photos to go along with the article.
russell...@yahoo.com
On Feb 3, 12:01 pm, "littlecirclesvt.com :: mike beganyi"
> Something many Randos have been discussing for some time, now
> apparently being tested in Finland:
>
>
> Wider is faster...
Not really. The text says:
" For an equivalent make and model of tyre, Wheel Energy claims the
25mm-wide size will measure five percent lower rolling resistance on
average – the supposed average limit of human detection – than the
more common 23mm-wide one."
Now some people might automatically assume that a 28mm tire will have
less rolling resistance than a 25mm tire. And a 32mm tire will have
less rolling resistance than a 28mm tire. And a 35mm tire will have
less rolling resistance than a 32mm tire. And a 40mm tire will have
less rolling resistance than a 35mm tire. And a 50mm tire will have
less rolling resistance than a 40mm tire. Etc., etc. These people
may be 100% wrong. Extrapolation works sometimes, but not always.
littlecirclesvt.com :: mike beganyi
William D. Volk
For nighttime riding it's great to ride fat. Tires that is.
Bill
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Alan Walker
Veronica Tunucci
Veronica
From the 1970s onward, it used to be 21.5 mm tubulars. About 5 years
ago, most pros went to 23 mm. Now some are riding 25 mm.
Why are they going to wider tires? It's not that the roads in France
are getting worse...
Some of the reasons are stated here:
http://www.cyclingnews.com/features/cervelo-testteam-get-testing-in-belgium
Interestingly, Cervelo believes that 25 mm is best. Coincidentally,
25 mm is the widest that fits their frames. So they cannot test wider
tires without making new frames.
As a side note, narrower tires, run at higher pressures, _feel_
faster to most riders, myself included. I believe this is because
higher tire pressures make the bike vibrate at higher frequencies.
All things being equal, higher vibration frequencies mean higher
speed - you are hitting the road irregularities in faster succession
the faster you go.
So pumping up your tires harder fools your body into thinking that
you go faster, even though your speed is the same.
It appears that professional racers, as well as many others (myself
included), used to ride very narrow tires because they felt faster,
even though they actually were slower.
With all this discussion of tire width, it's important to remember
that width is only a secondary factor in determining tire
performance. Much more important is the casing construction. Our tire
tests have shown - once again - that supple casings roll fastest.
Not coincidentally, top racing cyclists have been using hand-made
tires with extra-supple casings for at least the last 70 years. That
is one piece of cycling equipment that has not changed at all since
the days when PBP was a professional race.
Jan Heine
Editor
Bicycle Quarterly
2116 Western Ave.
Seattle WA 98121
http://www.bikequarterly.com
Follow our blog at http://janheine.wordpress.com/
Rick Martyn
Veronica Tunucci
That's easier said than done. :-)
V
-----Original Message-----
From: Jan Heine [mailto:hei...@earthlink.net]
Sent: Friday, February 04, 2011 10:21 AM
To: Veronica Tunucci
Cc: 'randon'
Subject: RE: [Randon] Re: Wide Tire Testing
>Any opinion on the Cervelo aero frame? Does that help with performance?
Maybe a little bit - might save 60 seconds over the course of PBP...
The aero effect of equipment appears to be very small. The best
numbers I have seen estimate that aero wheels decrease your drag by
2-3%.
Source: http://www.analyticcycling.com/WheelsConcept_Page.html
Because aerodynamic drag isn't the only resistance, a decrease in
drag of 2-3% means you'll go 1-2% faster. If you go 20 mph with
standard wheels, you'll go 20.02 - 20.04 mph with aero wheels.
Realistically, it's the rider you need to streamline, which is why
aerobars work so well.
Even aerobars appear to be a mixed blessing. In long-distance events
that allow aerobars, quite a few winners don't use them. Furnace
Creek 508 has been won several times in recent years without aerobars.
I used to ride with them, but found that they weren't so comfortable
beyond 150 miles. I was faster on the road, but spent more time
stretching at controls.
William D. Volk
One model, the Milan ... currently holds the 24hr record, 1219 km.
http://www.milan-velomobil.de/news.htm
SoCalRando
Thank you for all the good info you provide. Small correction on the
1-2% faster - from 20mph that would be 20.2 - 20.4 mph. While still
not huge, a lot more than 20.02 - 20.04. Of course you are one of the
few people who may actually have a 20mph rolling average.
Jim
On Feb 4, 10:21 am, Jan Heine <hein...@earthlink.net> wrote:
> >Any opinion on the Cervelo aero frame? Does that help with performance?
>
> The aero effect of equipment appears to be very small. The best
> numbers I have seen estimate that aero wheels decrease your drag by
> 2-3%.
>
> Source:http://www.analyticcycling.com/WheelsConcept_Page.html
>
> Because aerodynamic drag isn't the only resistance, a decrease in
> drag of 2-3% means you'll go 1-2% faster. If you go 20 mph with
> standard wheels, you'll go 20.02 - 20.04 mph with aero wheels.
>
> Realistically, it's the rider you need to streamline, which is why
> aerobars work so well.
>
> Even aerobars appear to be a mixed blessing. In long-distance events
> that allow aerobars, quite a few winners don't use them. Furnace
> Creek 508 has been won several times in recent years without aerobars.
>
> I used to ride with them, but found that they weren't so comfortable
> beyond 150 miles. I was faster on the road, but spent more time
> stretching at controls.
>
thirty-six
On Feb 4, 4:54 pm, Jan Heine <hein...@earthlink.net> wrote:
> >What size tyres are used by top racing cyclists (e.g., in Tour de
> >France) and why?
>
> ago, most pros went to 23 mm. Now some are riding 25 mm.
(20 or so models) from the late 70's and through 1980's seemed to be
predominantly for 24mm tyres judged by the seat bed radius.
Exceptions, probably later were for 'aero' rims, which would be
radiused for 20/21mm (time trialling) and large sections radiused for
28mm (cyclocross).
The seat bed radius of a sprint rim determines the smallest tyre that
can be mounted safely. You go smaller and the tyre can be prone to
rolling off, rim tape can help fit a small tyre to a larger rim, but
there's only so far you can go. It would not be in order for
professionals to be taking these risks.
My own Fiamme Ergal ( 280g lightweight racing) rims are for a 24mm
tyre. The narrow rim such as a Saturne HTS20 takes a 20mm tyre and
the rim only a little narrower. The tyre bed was modified to take a
23mm training tub with great results. BTW that is a cold assembled
cotton training tub, could be impossible to find today.
I was tempted to get some of the wide rims meant for crossing but the
availability of economical tubular tyres was and probably still is
zero in a 28mm section.
> Why are they going to wider tires? It's not that the roads in France
> are getting worse...
>
> Some of the reasons are stated here:
>
> Interestingly, Cervelo believes that 25 mm is best. Coincidentally,
> 25 mm is the widest that fits their frames. So they cannot test wider
> tires without making new frames.
>
> As a side note, narrower tires, run at higher pressures, _feel_
> faster to most riders, myself included. I believe this is because
> higher tire pressures make the bike vibrate at higher frequencies.
>
> All things being equal, higher vibration frequencies mean higher
> speed - you are hitting the road irregularities in faster succession
> the faster you go.
>
> So pumping up your tires harder fools your body into thinking that
> you go faster, even though your speed is the same.
>
> It appears that professional racers, as well as many others (myself
> included), used to ride very narrow tires because they felt faster,
> even though they actually were slower.
>
> With all this discussion of tire width, it's important to remember
> that width is only a secondary factor in determining tire
> performance. Much more important is the casing construction. Our tire
> tests have shown - once again - that supple casings roll fastest.
>
> Not coincidentally, top racing cyclists have been using hand-made
> tires with extra-supple casings for at least the last 70 years. That
> is one piece of cycling equipment that has not changed at all since
> the days when PBP was a professional race.
>
thirty-six
On Feb 6, 12:33 am, Jan Heine <hein...@earthlink.net> wrote:
>
> >On Feb 4, 4:54 pm, Jan Heine <hein...@earthlink.net> wrote:
> >> >What size tyres are used by top racing cyclists (e.g., in Tour de
> >> >France) and why?
>
> >> From the 1970s onward, it used to be 21.5 mm tubulars. About 5 years
> >> ago, most pros went to 23 mm. Now some are riding 25 mm.
>
> >This is an odd statement. Examination of stock of tubular road rims
> >(20 or so models) from the late 70's and through 1980's seemed to be
> >predominantly for 24mm tyres judged by the seat bed radius.
>
> rims, and they rode the then-predominant 21.5 mm tires. In fact, I
> used Fiamme Ergals on my front wheel for a decade, with 21.5 mm
> tires, and no problems.
It is not an ideal combination for racing. Contact pressure on the
outside of the wheel to tyre will reduce in a corner with narrow
section tyre on a medium section rim. Fit the tyre to the rim and the
pressure at the edges is higher than the centre, as the tyre squats,
compensating for the reduction in tyre contact pressure on the outside
through the corner. Then the tyre is certain to stay stuck.
>
> However, I was not involved in racing during the 1970s, and I haven't
> done extensive research on this subject, so I'll modify my statement
> above:
>
> "At least since the late 1980s, pro racers rode 21.5 mm tubulars.
> mm."
that is what the 'aero' rims of the time required, it was not a
wholesale operation. The professional races in the UK, many of them
criterium or criterium finish did see a mix of the traditional wheels
and the new 'aero' rim (raised edge) on the circuit at that time.
Training wheels were of the traditional variety. It'd be silly to
ride 100 miles twice in a day on narrow tyres. Can't say what
happened after about 1990
>
> The most pertinent part of my statement was that professional racing
> bikes' tires have become significantly wider over the last 10 years.
That's good to hear.
There is something about my bike #1 (essentially a criterium racer) in
that it does not have the accuracy of tracking with a front tyre of
25mm that a 23mm tyre has. This has fixed me to using tub's for their
comfort and control for when I fancy a speedy ride, I can buzz off,
which does not involve much rough stuff. Sometimes a wider tyre
spoils the fun, but I wholeheartedly agree with usiing wider tyres
than what has become common use with HPs. Some years ago an ex
clubmate told me a Michelin rep had been to the club to tell them the
benefits of 23mm tyres over 21mm, "FFS, I was using 25s when you were
using 21's" I reminded him. I went down to the very narrow 20mm
tyres and worked my way up (using chain gang as rerference). Racing
style tyres were limited to 25mm, and over 1lst7lb I always used a
25mm for a rear HP tyre, and lat4erly using this on the front as
well.
From what I'm now hearing, I may as well pull those old 27x1.1/4's
from the loft and use them on #2 . It doesn't surprise me.