Brevet tire brand?
BEN STAGGS
Dave Cramer
I've been pleased with the Michelin Pro2 Race 25mm tire so far. Feels
(and tests) fast, and no durability problems so far. It measures
almost 27mm on my Aerohead rims.
I'd love to use the Grand Bois 700c x 30, which should be more
comfortable, but I don't quite have the necessary clearance under my
fenders...
Dave
Robert Magyar
You have to provide us with some additional information before your question can be answered.
Like how much much do you and your bike weight when it is loaded for a brevet?
i.e. rider in bike clothes, camelback full of water, bike with spare tire and tubes total weight = 200 Lbs.
What width rims do you have? Open Pro's, MA3's, CR-18's, Dyad's all have different widths, and could effect the tire selection.
Does your frame have lot's of clearance, or can it only fit a 23 wide tire?
I am assuming that you are talking about 700c tires.
Any one who replies to your post, should also provide this information and at what pressure they run their tires.
Also, have you your searched this google list for recent posts on this subject? There have been a few.
Bob
From: STAGG...@MSN.COM
To: ran...@googlegroups.com
Subject: [Randon] Brevet tire brand?
Date: Wed, 16 May 2007 16:35:33 -0600
BEN STAGGS
Cary Way
www.schwalbe.com
Cary Way
>From: "BEN STAGGS" <STAGG...@MSN.COM>
>To: <ran...@googlegroups.com>
>Subject: [Randon] Brevet tire brand?
>Date: Wed, 16 May 2007 16:35:33 -0600
>
_________________________________________________________________
More photos, more messages, more storage—get 2GB with Windows Live Hotmail.
http://imagine-windowslive.com/hotmail/?locale=en-us&ocid=TXT_TAGHM_migration_HM_mini_2G_0507
Don Perley
you can search to see what's been thrashed already.
Anyway, I like Kevlar belted tires. I've never gotten a flat with one
in less than 3000 miles, ymmv. Current favorite is Specialized Mondo.
Their Armadillo is heavier, sturdier (with sidewall Kevlar), and
available in more sizes.
jo...@johnandjuliet.com
lot...
I've got two bikes I use for rando rides. One is my litespeed which
is setup with Spinnergy 45mm dished wheels and aero bars.
It is typically used for 24 hour racing but it is also my bike of
choice for up to 400ks... Fast and moderately light and all I carry
is 3 spare tubes and a spare tire.
As for the tire.. I run 20mm Michelin carbon which I think are now
called carbon Krillons?
On my airborne touring bike which can handle larger tires I change
them depending on the weight and how rough I expect the roads to be.
Typically I'll run up to 25mm (Krilions) but I've run 28mms when I'm
doing medium loaded touring...
Bottom line is this: I love michelin tires as a geneneral rule even
the Pros though I tend to go with the slightly less expensive carbons
(Krilons now) which are only a tad heavier.
Haynes, Davy A. (MSFC-EV33)
Ben,
For randonneuring use, those delicate boutique wheels are a poor choice. They offer no margin nor are they field repairable. I would recommend you address that before worrying over tire selection.
Regards,
Davy Haynes
-----Original Message-----
From: ran...@googlegroups.com on behalf of BEN STAGGS
Sent: Wed 5/16/2007 6:27 PM
To: ran...@googlegroups.com
Subject: [Randon] Re: Brevet tire brand? With specs. this time.
I see, rider plus bike is 210lbs, and add 10lbs. of gear and water for 220lbs approx. for the machine and pilot during the brevet. It is good to see the weight in print actually, I weigh 185 myself and the bike is approx 25lbs. So I am neither ulralight nor Clydesdale division.
I am using Mavic rims: Ksyrium Equipe (622x13) 20 spoke fr, 24 spoke rear. 700cc I might add. A 23mm tire is what I want to use, of that I am positive.
The frame is a Litespeed Catalyst built in 1994/5, and 23 mm clearence is all there is. I use a recommended tire pressure, ie., I follow what is printed on the tires. I hope to not be wasting to much space with this, thanks Ben Staggs
----- Original Message -----
From: Robert Magyar<mailto:bob_m...@hotmail.com>
To: BEN STAGGS<mailto:stagg...@msn.com> ; ran...@googlegroups.com<mailto:ran...@googlegroups.com>
Sent: Wednesday, May 16, 2007 5:02 PM
Subject: RE: [Randon] Brevet tire brand?
Ben,
You have to provide us with some additional information before your question can be answered.
Like how much much do you and your bike weight when it is loaded for a brevet?
i.e. rider in bike clothes, camelback full of water, bike with spare tire and tubes total weight = 200 Lbs.
What width rims do you have? Open Pro's, MA3's, CR-18's, Dyad's all have different widths, and could effect the tire selection.
Does your frame have lot's of clearance, or can it only fit a 23 wide tire?
I am assuming that you are talking about 700c tires.
Any one who replies to your post, should also provide this information and at what pressure they run their tires.
Also, have you your searched this google list for recent posts on this subject? There have been a few.
Bob
----------------------------------------------------------------------------
Jim Bronson
for randonneuring durability.
However, if you are insistent on using them AND 23mm tires (why?), I
would suggest the Continental Ultra Gatorskin for durability.
If you think the Gatorskins ride too harshly, then try the Michelin
Pro2 Race. They are more durable than most light racy tires and they
ride really nice also.
Personally, I ride Velocity Deep V rims with 32 spokes and 28mm tires
on brevets, but to each his own I guess. I am admittedly much taller
and heavier than you.
On 5/16/07, BEN STAGGS <STAGG...@msn.com> wrote:
>
>
>
--
I am riding the MS150 bicycle rally from Houston to Austin on April 21
and 22, 2007. 164 miles by bicycle! Will you join me and make a
pledge to support multiple sclerosis research? Donate online at my
link: http://ms150.org/edon.cfm?id=182433
Peter Jon White
> 5. When calculating the time you can gain using ultra-fast tires in
> PBP, compared to kevlar-belted "sturdy" tires, we found that it
> varies between about 3 hours for the fastest riders and more than 10
> hours for the slowest ones, for whom rolling resistance makes a
> greater portion of the overall resistance (less wind resistance at
> lower speeds).
Since the slowest PBP finishers have ninety hours, and you're claiming a
ten hour time savings, are you claiming a speed increase of over 10%? Or
am I missing something?
--
Peter Jon White
Peter White Cycles
24 Hall Rd.
Hillsborough, NH 03244
603 478 0900 Phone
603 478 0902 Phax
www.PeterWhiteCycles.com
Tom Worster
> 5. When calculating the time you can gain using ultra-fast
> tires in PBP, compared to kevlar-belted "sturdy" tires, we
> found that it varies between about 3 hours for the fastest
> riders and more than 10 hours for the slowest ones
what was the Cr basis of this calculation? i.e. what was the
coefficient of rolling resisistance you assumed for the
'ultra-fast tires' and for the 'kevlar-belted "sturdy" tires'?
Jim Bronson
One one hand, I am grateful to you for providing this information online.
On the other hand, I have never seen the meat of the VBQ article that
you and others continuously refer to.
So how much is it going to cost to acquire the back articles of VBQ/BQ
that I will need in order to actually read the tire articles in
question that seem to be CONTINUALLY referred to on this and other
randonneuring lists?
See what I'm getting at? At times providing these bits and pieces
seems almost like advertising for your magazine. Well, it's working,
I'm about to buy it for 2 years.
Anyways...
The idea that we should worry more about speed than puncture
resistance is a radical one to this randonneur. But, I wouldn't mind
dumping the 28mm Conti UltraGatorskins in favor of something faster,
I'll just have to get my mind around the idea of changing flats more
often, I guess. I took my sporty bike shod with 700x23 Pro2Race on a
recent 2 day charity ride and it is most definitely faster even though
it actually weighs MORE than my Rivendell does. (steel is real!)
Your Grand Bois Cyprès 700x30 sound nice and I'm pretty sure they'd
fit, even with my short reach brakes, on my Rivendell.
On 5/17/07, Jan Heine <hei...@earthlink.net> wrote:
>
> Bicycle Quarterly tested the rolling resistance of a number of
> popular tires on typical brevet road surfaces (rather than
> ultra-smooth steel drums), and found some interesting results
> (published in the Autumn 2006 and Spring 2007 issues):
>
> 1. Tire rolling resistance varies more than we thought.
>
> 2. Some tires thought (and claimed) to be fast are not fast at all.
>
> 3. Narrower tires have higher resistance generally. A 25 mm Michelin
> Pro2 Race rolls faster than a 23 mm, which rolls faster than a 20 mm.
> (That was known before.)
>
> 4. On normal road surfaces, ultra-high pressures make your bike
> vibrate more. This counters the advantage gained from the reduced
> tire deformation. Basically, running a tire at comfortable pressures
> is no slower than running it at very high ones.
>
> 5. When calculating the time you can gain using ultra-fast tires in
> PBP, compared to kevlar-belted "sturdy" tires, we found that it
> varies between about 3 hours for the fastest riders and more than 10
> hours for the slowest ones, for whom rolling resistance makes a
> greater portion of the overall resistance (less wind resistance at
> lower speeds). (We also calculated the advantages of aero wheels and
> lighter bikes, which paled in comparison, gaining you a couple of
> hours at best. "Climbing" wheels don't give you a measurable
> advantage at all.)
>
> I tried this on the road, using the fastest tires in our test for a
> 600 and a 1000 km brevet last year, on my usual bike with its usual
> equipment otherwise. Both brevets resulted in personal bests, about
> 8-10% faster than my usual times, even though the conditions were
> below average with rain in one brevet, headwinds in the other. (My
> times were 22:48 for the 600, 43 hours and change for the 1000 -
> maybe I was lucky - I had not flats). In other brevets, I rode my
> "standard" tires, which tested in the middle of the pack, and was no
> faster than usual. The combination of our tests and on-the-road
> experience shows that tires really make a difference in speed - not
> to speak of comfort.
>
> Basically, unless you are a very flat-prone rider (bad luck, not
> scanning road ahead, brevets in glass-strewn areas, etc.), fast tires
> will gain you more speed than you will loose fixing the occasional
> flat.
>
> On our recent brevet, an experienced rider was on Continental 20 mm
> tires. First, he lost contact with the lead group when one of his
> tires split at the sidewall after some bumpy roads. Fortunately, he
> carried a spare. Then, toward the end, he had terrible cramps after
> riding over some very rough chipseal. I was riding 30 mm Grand Bois
> tires, which not only are faster, but also more comfortable.
>
> Choosing your tires wisely appears to be the biggest equipment
> improvement you can make to your bike.
>
> Disclaimer: Vintage Bicycle Press sells Grand Bois tires.
>
> Jan Heine
> Editor
> Bicycle Quarterly
> 140 Lakeside Ave #C
> Seattle WA 98122
> www.bikequarterly.com
Stephane Beaudry
using them, did the whole 400 and 600 without one flat, but on the 300, I
used the Michelin Pro2 Race and got one flat (and many others over the
months with theses), both tires are real tight on my rims, making them a
pain to fix on the side of the road, so I usually loose a good 15 minutes
changing a flat. In the 400, two guys were consistently swapping places with
me, I would be in front of them, they would pass me, I would later pass them
either because they stopped for supplies or had a flat. So I came to the
conclusion that Flat resistance was a big plus, but now I am a little
chocked to see Jan's test results showing a potential increase in speed of
10% is simply amazing, I never thought a change to my equipment could yield
that much of a gain...
----- Original Message -----
From: "Jim Bronson" <jim.b...@gmail.com>
To: "BEN STAGGS" <STAGG...@msn.com>
Cc: <ran...@googlegroups.com>
Sent: Wednesday, May 16, 2007 9:32 PM
Subject: [Randon] Re: Brevet tire brand? With specs. this time.
>
littlecircles :: mikeb
Jim Bronson wrote:
.
>
> So how much is it going to cost to acquire the back articles of VBQ/BQ
> that I will need in order to actually read the tire articles in
> question that seem to be CONTINUALLY referred to on this and other
> randonneuring lists?
>
> See what I'm getting at? At times providing these bits and pieces
> seems almost like advertising for your magazine. Well, it's working,
> I'm about to buy it for 2 years.
>
I did this, for the tire and randonneuring information, as well as to
support an interesting little magazine that has no compare in the
'buycycling' market. (and I'm interested in bike history...)
Am I a retrogrouch? Hardly... but I like the take and personal
experiences that find their way into BQ, and it is such a fresh look
at cycling when the web and the printed media seems clouded by
upgrading to unobtanium to go faster, and buying every little gadget
under the sun.
Its a good mag. If you don't want to keep them around - buy a
subscription for your local library and share...
That said, I'm running Continental 4 Season GP 28s and have found a
sweet spot of between 80 and 90 psi. They are much faster than the
Schwalbe Marathons I was running (the ones with 'puncture' resistant
layers) - and I'll be testing them against some Panaracer Pasela's
next week.
I've ridden the Conti GP 4 seasons for 3 years now. I have them in 23,
25, and 28mm widths, depending on which bike they ride under. I can
say that the width and reduced pressure does not seem to matter much
(when ridden on the same bike) in terms of how speedy they feel - but
the comfort difference is huge.
-Mike
cr...@rcn.com
However, given that frequency, and the fact that you've also engaged in discussions about this in other publications, like the letters column of Adventure Cycling's newsletter (Sheldon Brown v. Jan Heine cage match!) I think it would be a great service to the cycling community as a whole if a PDF of that article was available. I realize that you have a similar article online with a brief overview of the relationship between weight, low pressure and comfort, but that isn't quite as thorough as the later article, and its range of tested tires isn't as comprehensive.
It would facilitate a lot of discussion between advocates who insist on the direct causal relationship between thin tire widths, high pressure and faster times, and the revisionist idea that wider tires with lower pressures can be just as fast. As it is, the former group can link to various online articles as supporting documentation, but all the latter can say is, "well, if you go to this website and plunk down $10 for this dead-tree newsletter, then you'll see what we mean."
That doesn't make for the most convincing online argument.
Jim Bronson
subscribers only area on the website where this content was archived
and available.
I am not sure what additional costs would be incurred by BQ to provide
this service either in web hosting, software or administrative costs,
just saying that, I would be interested.
mbiswell
>From: Jan Heine
>Sent: Thursday, May 17, 2007 8:24 AM
>The Pro2 Race were among the faster tires we tested...
And that's all I need to know, and they're French too! Thanks!
Regards!
Ps. Props to all Mavic rims for ease of tire changes, even the 20/24 spoke
Ksyriums, which are easily as good as a spoked wheel for brevets, and not to
be excluded from the conversation. They do kite about in a crosswind some,
but they are road repairable, which different than stated here, and it's
much rarer that you hear about a broken "boutique" spoke, than the very
common broken spoke we always see. The "boutique" spokes are just a lot
bigger than a normal spoke, and therefore stronger. Just please make sure to
get the more pricey ones and all will be fine. :-)
Mark Carry
I wanted to make this observation as I was a bit unsure of what you meant by the "bigger" "pricier" spokes.
-Mark
Haynes, Davy A. (MSFC-EV33)
>20/24 spoke
>Ksyriums, which are easily as good as a spoked wheel for
>brevets, and not to
>be excluded from the conversation. They do kite about in a
>crosswind some,
>but they are road repairable, which different than stated
>here,
Really. Where does obtain spare "spokes" for them? None of our local
shops here carry them. Certainly don't expect to find one in a Carhaix
or Loudeac bike shop during PBP.
>and it's
>much rarer that you hear about a broken "boutique" spoke, than the very
>common broken spoke we always see.
Not in my experience. Perhaps you should seek out a more competant
wheel builder.
I've seen several so-called "bomb-proof" Kysrium wheels with broken
spokes and split rims. Rec.bikes.tech is full of shop owners reporting
similar experience.
The "boutique" spokes are just a lot
>bigger than a normal spoke, and therefore stronger.
Some are bigger because they are made of aluminum, which is a poor
choice of spoke material, it having no endurance limit and thus subject
to fatigue failure in an application that has high fluctuations in
stress every revolution of the wheel. The angular "aero" shape makes
this an even worse situation, concentrating stress risers as they do.
If you've not had any problems with Krysium wheels that is fortunate for
you, but anecdotal. The many failures reported confirm that these
wheels do fail fairly regularly, and I don't think you will find many
[experienced] randonneurs that have a high opinion of them (or other
such low-spoke count wheels).
Regards,
Davy Haynes
Charles Coldwell
>
> I've seen several so-called "bomb-proof" Kysrium wheels with broken
> spokes and split rims.
A guy I was riding with broke a spoke in a Kysrium wheel on B-M-B last
year. He had to replace the whole wheel. It cost him hours.
Chip
--
Charles M. Coldwell
"Turn on, log in, tune out"
Somerville, Massachusetts, New England
mbiswell
>From: Mark Carry
>Sent: Thursday, May 17, 2007
9:59 AM
>Mavic
Ksyrium's come in several models, some with aluminium spokes (zicral) and
others with steel, in varying widths of bladed
configurations. The zircal >spokes tend to by a very wide blade which
could contribute to the 'kiting' you notice but from the Elites on down they
are not nearly so wide. The commonality is >that they are straight pull rather than being bent at the head which is the
point at which many spoke failures occur. The ES and SL models require
special spoke >tools
to repair, which you could carry with you along with a spare spoke or
three. From the Elites on down they do allow for standard repair
procedure on the >road
as long as you have the spares.
>I wanted to make
this observation as I was a bit unsure of what you meant by the
"bigger" "pricier" spokes.
Hi Mark,
Yes, thanks for this clarification – “by pricier,” sayin’ that I’ve read mixed reviews about the lower tier Ksyriums (Elites?), which are (some of?) the ones without the bladed spokes. Also I think there might 2 grades of bladed spokes. Whatever, it’s easy to change a flat on a Mavic rim which luv much.
Yes, to ride Ksyriums on a big brevet, you need a repair kit which should contain the spoke tools and 2 x each of 3 sizes of spokes, total 6, or maybe 9 spokes.
Regards!
Haynes, Davy A. (MSFC-EV33)
>year. He had to replace the whole wheel. It cost him hours.
>
Not to mention $$'s.
Haynes, Davy A. (MSFC-EV33)
>Yes, to ride Ksyriums on a big brevet, you need a repair kit
>which should contain the spoke tools and 2 x each of 3 sizes
>of spokes, total 6, or maybe 9 spokes.
>
I would rather just ride a more robust wheel with 32 or 36 spokes than
ride a marginal wheel, carrying spare spokes to make up the difference.
So it would seem we are both carrying about the same number of spokes,
it's just that ALL of mine are being useful.
Grins,
Davy
Don Perley
article maybe 3 decades ago, was that an average racing bike going
steady 20 mph on a flat, smooth, windless road used 98% of the power on
wind resistance, and 2% on everything else (rolling resistance,
bearings, chain, idler pulleys, etc). Some deviation could be
attributed to rider size, measurement technique etc, your postings
indicate they were low on the mechanical losses by well over an order of
magnitude. That has to raise questions of how you measured the Crr so I
can understand that vast difference.
Charles Coldwell
I should have been more clear -- he had to have a mechanic deliver a
spare wheel because a field repair of the Kysrium was impossible with
the tools at hand. The Kysrium wheel was not destroyed, and was
repaired after B-M-B.
However, it is much easier to just carry a fiber-fix spoke for a
standard 36-spoke wheel.
Peter Jon White
> Mavic Ksyrium's come in several models, some with aluminium spokes
> (zicral) and others with steel, in varying widths of bladed
> configurations. The zircal spokes tend to by a very wide blade which
> could contribute to the 'kiting' you notice but from the Elites on down
> they are not nearly so wide. The commonality is that they are straight
> pull rather than being bent at the head which is the point at which many
> spoke failures occur.
Spokes only fail at the bend if the spoke tension is too low. If your
wheels are properly built, this simply won't happen.
The Mavic Ksyrium wheels are undoubtedly very good wheels for those
racers who are supported or those riders who can afford to replace
wheels every couple thousand miles, particularly if the rider in
question is the typical 145lb Cat 2 type.
I feel sorry for the big 200 lb guys who've been sold these "ultralight"
wheels, thinking that they'll climb hills faster having saved a few
dozen grams. Of course they don't climb any faster, but their wallet is
certainly lighter.
Mark Carry
-Mark
mbiswell
>From: Charles Coldwell [mailto:cold...@gmail.com]
>Subject: Re: [Randon] Re: Brevet tire brand?
>However, it is much easier to just carry a fiber-fix spoke for a
>standard 36-spoke wheel.
>Chip
Yes, okay easier, but also some riders carry spokes, anyways too - maybe
even you sometimes.
And if you can save 10 hours with just good tires, then wheel rolling weight
and wheel aero aspects will save you another 5 hours, right?
Await consensus reply to Don P's message (and where this all meets at 15mph,
not 20mph) so I can pick my brevet wheelset, my "sturdy" 32/36 spoke
ultegra/mavic open pros or my "speedy" campy neutrons, the ones with the
with the desired offset rear rim...
How can a bike go faster?
Regards!
Mark Carry
What really gets me are the little bitty guys riding around on Ksyrium SL's. Must be a pretty stiff ride.
-Mark
Haynes, Davy A. (MSFC-EV33)
>
>However, it is much easier to just carry a fiber-fix spoke for a
>standard 36-spoke wheel.
>
Yep--that's what I do. Although that's primarily protection for crash
damage. If I were to break one spoke, I'd likely just true it up a bit
and ride on, replacing it after the event. Nice thing about such wheels
in they are robust and can suffer a broken spoke without much fuss.
I've riden hundreds of miles with a broken spoke. A Ksyrium with a
broken spoke will not rotate past the chainstays on most
bicycles--precluding even riding to the next control for assistance.
Davy
littlecircles :: mikeb
Mike "I hate bladed spokes because I cut my hands on them whilst
working on my bike*" Beganyi
*speaking of some sort of Bontrager Race Lite wheels on my LeMond
Haynes, Davy A. (MSFC-EV33)
>Spokes only fail at the bend if the spoke tension is too low. If your
>wheels are properly built, this simply won't happen.
>
break spokes short of a crash, stick in the spokes, or dropping the
chain into them. (Of course, "well selected" may mean a 40 spoke rear
wheel for the largest of randonneurs).
>The Mavic Ksyrium wheels are undoubtedly very good wheels for those
>racers who are supported or those riders who can afford to replace
>wheels every couple thousand miles, particularly if the rider in
>question is the typical 145lb Cat 2 type.
>
I guess that's why the hubs are not very serviceable as well--the
thought being they will be replaced before the bearings need repacking.
I guess I'm just not hip to the throw away/buy new mentality either.
Some call this being a "retro grouch." I think it is simply being
practical and not wasteful.
Davy
Haynes, Davy A. (MSFC-EV33)
>Fenders, anyone?
>
LOL, but that's child's play. Why not start a good helmet flamefest?
Grins,
Davy
littlecircles :: mikeb
Bill Gobie
calculator at AnalyticCycling.com gives 39 watts for rolling
resistance and 108 watts for air drag using Crr = 0.006 and default
values for other inputs. That's 27% of total power into rolling
resistance and 73% for air drag.
The total power of 147 watts leaves me wondering why I only go 14
mph, but even if you fuss around with the calculator's inputs there
is no way you can put 98% of power into air drag with realistic
values for Crr and drag area.
The Sci Am article you are referring to might have been written by
Chet Kyle in the early '80s. Unfortunately I can't find the article
itself online anywhere.
Bill
Adrian Hands
> wheels are properly built, this simply won't happen.
Okay, i've had a few break spokes break at the bend, mostly on old
1980s road bikes that I'd picked up at yard sales etc... Those spokes
were different from my nice brevet bike: dull in color and rough to
touch. Is that aging and weathering or a different material (e.g.
galvanized vs stainless)?
On my brevet bike, with nice shiny spokes, I had three spokes break
within a space of a few weeks. They broke just below the nipple (i.e.
close to the rim, not the hub). I can understand a spoke that is too
loose breaking at the bend where it slides through the hole in the
flange, but why would they break near the nipple like that? I don't
know if it was three different spokes or if the replaced spoke broke
again.
Haynes, Davy A. (MSFC-EV33)
>98% of power lost to air drag is way too high. The Power Given Speed
>calculator at AnalyticCycling.com gives 39 watts for rolling
>resistance and 108 watts for air drag using Crr = 0.006 and default
>values for other inputs. That's 27% of total power into rolling
>resistance and 73% for air drag.
>
That 27% is not all rolling resistance of the tires, but includes
drivetrain and bearing losses as well.
Davy
Haynes, Davy A. (MSFC-EV33)
>On my brevet bike, with nice shiny spokes, I had three spokes break
>within a space of a few weeks. They broke just below the nipple (i.e.
>close to the rim, not the hub). I can understand a spoke that is too
>loose breaking at the bend where it slides through the hole in the
>flange, but why would they break near the nipple like that?
That's an easy one--the spoke line was not corrected. Find a better
builder.
Davy
Steve Palincsar
>>Spokes only fail at the bend if the spoke tension is too low. If your
>>wheels are properly built, this simply won't happen.
>
>
> Okay, i've had a few break spokes break at the bend, mostly on old
> 1980s road bikes that I'd picked up at yard sales etc... Those spokes
> were different from my nice brevet bike: dull in color and rough to
> touch. Is that aging and weathering or a different material (e.g.
> galvanized vs stainless)?
Back in the day they used galvanized spokes. Some of the spokes of the
day were OK, some were utterly horrible. Many broke for no good reason,
just that they were crap.
I remember it well: I had to replace 36 spokes in the back wheel of my
P15 Paramount one lousy spoke at a time (and every one was a 2 hr round
trip to the not-so-very-local LBS).
littlecircles :: mikeb
Adrian Hands wrote:
They broke just below the nipple (i.e.
> close to the rim, not the hub). I can understand a spoke that is too
> loose breaking at the bend where it slides through the hole in the
> flange, but why would they break near the nipple like that? I don't
> know if it was three different spokes or if the replaced spoke broke
> again.
Alloy or brass nipples?
I've switched to brass all around, as riding in all weather I had this
happen a few times.
The metals oxidize / react (scientific term here) or something... and
then they start snapping, right at the thread into the nipple.
Glenn Ammons
> Thus, at 20 mph, rolling resistance (bearings, tires, etc.) makes up
> between 33 Watt (141-108) and 65 Watt (173-141), or between 23% and
> 38% of the overall resistance.
>
> That still means that 62% to 77% of your overall resistance is due to
> aerodynamic drag...
Shouldn't you also account for wind? Wind hurts you most of the time
and there's usually _some_ wind. So, if you average 15 mph on a ride,
you have to overcome more than 15 mph worth of wind resistance (on
average).
--glenn
Albany, NY, USA
Don Perley
> At 1:38 PM -0400 5/17/07, Don Perley wrote:
>> A rule of thumb I had been using, gotten from a Scientific American
>> article maybe 3 decades ago, was that an average racing bike going
>> steady 20 mph on a flat, smooth, windless road used 98% of the power
>> on wind resistance, and 2% on everything else
>
>
> When you go to analyticcycling.com and reduce the rolling resistance to
> 0 (make sure you also reduce the slope to 0), you find you need a power
> output of only 108 Watt to go 8.9 m/s (20 mph). All you overcome now is
> wind resistance. At 20 mph, that takes 108 Watt.
>
> When you add rolling resistance - by putting in a good racing tire Crr
> of 0.005, you need 141Watt to attain the same speed. Putting in a
> "sturdy" tire, but not the worst we tested (Crr=0.01), you need 173 Watt.
>
> Thus, at 20 mph, rolling resistance (bearings, tires, etc.) makes up
> between 33 Watt (141-108) and 65 Watt (173-141), or between 23% and 38%
> of the overall resistance.
OK, I went there and ran some numbers. I set Cd to .9 since I've seen
that number in a few places for both bicycles and unfaired motorcycles
(which have similar shapes, though different areas). Most of the
examples on the site are for time trials, but they don't say the riding
position assumed for the default in the drag calculator. They do
recommend the higher end of the range if you are big, so I set that to
.7 m2, rider weight to 81 kg, bike weight to 9 kg. I set Crr to their
recommended .001 for wood track. The program returned that 2.7 percent
of drag was from rolling resistance. That's at least in the same
ballpark as the old article.
I know wood track is not a reasonable assumption for brevet riding, but
figured maybe Sci-Am used a track. Long enough ago that I don't
remember that detail.
20 mph is certainly higher that average speed for long brevets, but not
unusual for the flat parts.
-Don
li...@jkassen.org
> The metals oxidize / react (scientific term here) or something... and
> then they start snapping, right at the thread into the nipple.
I once had a bunch of nipples break after 2 years on a wheel I hand built. Actually this was first wheel I ever "built" -- Emily taught me and wound up doing most of the work. To make a long story short, my spokes were all 1-2mm too short. One of the better LBS told me that the program that most LBSs use to calculate spoke length tends to give results that are 2mm too short. Sure enough that wheel was the only one that I had the LBS do the calculation for the spoke lengths -- every wheel I have built since I've used the spocalc.xls program on Sheldon Brown's site. I have no idea what program bike shops use or if it really does report spoke lengths that are too short, but short spokes were to blame for my nipple breakage. BTW that is the only problem I've had on all the dozen-odd wheels I've hand built.
As for what wheels to use on Brevets, I'm a firm believer on using what you find comfortable and trust. For me I wouldn't use any wheel where a single broken spoke would prevent me from continuing and finishing the ride.
As for tires, I used to use the $10 nashbar kevlar belted 700x23 tires but switched to Pro II Race tires after reading the BQ article. I can definitely feel a difference and I don't think I'll go back to the cheaper/thinner tires for long rides. That said, spending $75+ on tires a few times a year really hurts. It is a real shame that long distance cycling costs so much, especially if you take the frequent suggestions of the list and newletters.
Jake "Cycling should be cheap" Kassen
littlecircles :: mikeb
> That said, spending $75+ on tires a few times a year really hurts. It is a real shame that long distance cycling costs so much, especially if you take the frequent suggestions of the list and newletters.
>
> Jake "Cycling should be cheap" Kassen
After spending a foolish amount of money on a new bike and all its
components I'm not starting to agree. I built up a FG this winter for
cheap (compared to my custom machine with fancy parts) and I ride it
just as much (time, not yet up on the mileage)
And, after deciding that my wife and I are in a 2 incomce trap and we
are simplifying life - one of the things in the cross hairs is bike
stuff. I doubt we'll ever get there - we've got a list of priorities
more expensive than riding... but I tend to agree. We do get caught up
in whatever culture we surround ourselves with - be it Randon, BQ,
buycycling, etc.
littlecircles :: mikeb
"After spending a foolish amount of money on a new bike and all its
Not sure how the not made it in there. Wishful thinking I guess...
Charles Coldwell
> >OK, I went there and ran some numbers. I set Cd to .9
>
> >are big, so I set that to .7 m2,
>
> Bicycling Science quoted some actual wind tunnel data done by German
> magazines (I think it was TOUR again), and the frontal area of a
> rider on a bike with drop bars was somewhere around 0.35 m2. So about
> half of what you put in. This obviously means that you greatly
> overestimate the aerodynamic resistance...
Quoting from the same source (Bicycling Science, 3rd ed p. 211):
"For bicycle tires on a smooth hard surface, Cr is usually considered
to be between 0.002 and 0.010, depending on inflation pressure, wheel
diameter, and tire construction. For a bicycle-plus-rider mass of 80
kg, the total weight carried is 784 N, and the total rolling drag is
between 1.5 N and 7.8 N (0.3 lbf to 1.75 lbf). For comparison,
aerodynamic drag in low-wind conditions typically ranges between 5 N
and 30 N in level riding, depending on speed (figure 6.2)."
If your speed is 20 MPH or 8.941 m/s, then the rolling resistance
power required ranges between 13.4 W (1.5 N * 8.941 m/s) and 70 W (7.8
N * 8.941 m/s).
Again quoting from David Gordon Wilson,
"... express aerodynamic drag force as aerodynamic-drag factor Ka
times relative air velocity squared.... In standard international
units (SI), the drag factor Ka is in units o fkg/m, or equivalently
N/(m^2/s^2). For a rider on a bicycle, the drag factor is typically
between 0.1 (small person, recumbent position, snug clothing, in hot,
low-pressure, humid air [ick]) and 0.3 (larger person sitting upright,
with bulky loose clothes, in cold, high-pressure, dry air [much
better]).... As an example, consider a rider with drag factor Ka =
0.2, travelling at a speed of 10 m/s (22.4 mile/h). The aerodynamic
drag force at that speed is 0.2 * 10^2 or 20 N (4.5 lbf). The power
level is 20 N * 10 m/s = 200 W, which can be sustained for hours by a
fit cyclist [!] (see figure 2.4)".
Anyway, DGW's "typical" fit cyclist develops 250 W, and puts 20% of
that against rolling resistance and 80% against the wind on level
ground.
A couple of things to point out: The force due to rolling resistance
is constant, independent of speed (in that respect, it's like
climbing). The force due to wind resistance grows quadratically with
speed. Therefore, as you go faster, wind matters more and more.
Haynes, Davy A. (MSFC-EV33)
>
>Anyway, DGW's "typical" fit cyclist develops 250 W, and puts 20% of
>that against rolling resistance and 80% against the wind on level
>ground.
>
Again, either you've lumped other losses in with rolling resistance, or
left them out entirely. Where are frictional losses in the drivetrain,
and frictional losses in the wheel bearings? They can be small, but are
on the order of rolling resistance losses.
>A couple of things to point out: The force due to rolling resistance
>is constant, independent of speed (in that respect, it's like
>climbing). The force due to wind resistance grows quadratically with
>speed. Therefore, as you go faster, wind matters more and more.
>
True, but frictional losses in the drivetrain vary widely dependant upon
lubrication/cleanliness of chain, chain allignment, BB bearing
condition, etc. For example, cross-chaining has greater friction than
when running in a gear with near perfect chain allignment.
My point is, don't assume that all power not used to overcome
aerodynamic drag is used to overcome rolling resistance. This is a
common error, and overly inflates the impact of rolling resistance.
Regards,
Davy
Charles Coldwell
>
> >
> >Anyway, DGW's "typical" fit cyclist develops 250 W, and puts 20% of
> >that against rolling resistance and 80% against the wind on level
> >ground.
> >
>
> Again, either you've lumped other losses in with rolling resistance, or
> left them out entirely. Where are frictional losses in the drivetrain,
> and frictional losses in the wheel bearings? They can be small, but are
> on the order of rolling resistance losses.
Certainly, frictional losses in the wheel bearings are included in
rolling resistance. Think about the way rolling resistance is
measured: you put a rider and bike at the top of an incline of known
height and see how far he rolls without pedaling after coming off the
end of it. So the analysis extends to any friction in any part of the
bicycle that could be moving when you are not pedaling.
As to the drive train, well, I think it's small but I can't prove it.
Charles Coldwell
> >A couple of things to point out: The force due to rolling resistance
> >is constant, independent of speed (in that respect, it's like
> >climbing). The force due to wind resistance grows quadratically with
> >speed. Therefore, as you go faster, wind matters more and more.
>
> roughly linearly. So twice the speed will get you somewhere around
> twice the rolling resistance, but four times the wind resistance.
You're talking about power, I was talking about force. We're in
violent agreement here.
Charles Coldwell
> On 5/18/07, Jan Heine <hei...@earthlink.net> wrote:
> > >A couple of things to point out: The force due to rolling resistance
> > >is constant, independent of speed (in that respect, it's like
> > >climbing). The force due to wind resistance grows quadratically with
> > >speed. Therefore, as you go faster, wind matters more and more.
> >
> > Rolling resistance isn't constant, but does grow with speed, but
> > roughly linearly. So twice the speed will get you somewhere around
> > twice the rolling resistance, but four times the wind resistance.
>
> You're talking about power, I was talking about force. We're in
> violent agreement here.
Actually, we're not. So let's see if we can get there.
The force of rolling resistance is some constant (we can argue about
its value later) times the weight on the wheels. That expression
certainly doesn't depend on speed. The power is that force times the
speed, so the power is strictly proportional to speed and grows
linearly.
The force of wind resistance is quadratic in the speed. The power is
that force times speed, and therefore cubic -- the power required to
overcome wind resistance grows as the speed cubed.
Right?
Tom Worster
> The force of rolling resistance is some constant (we can
> argue about its value later) times the weight on the wheels.
> That expression certainly doesn't depend on speed. The power
> is that force times the speed, so the power is strictly
> proportional to speed and grows linearly.
>
> The force of wind resistance is quadratic in the speed. The
> power is that force times speed, and therefore cubic -- the
> power required to overcome wind resistance grows as the speed
> cubed.
>
> Right?
yes.
that is, to a pretty good approximation. rolling and fritcion
losses are typically modelled as proprtional to the normal
reation force in high school physics. air drag force varies
as the square of velocity relative to the air.
certainly good enough approximations for our purposes here.
Tom Worster
> The numbers I have seen indicate that they are much
> smaller than rolling resistance losses (see below).
that's my understanding too. good quality hub bearings in
good condition and correctly adjusted can be ignored for
these calculations. the freewheel mechanisms will have a
little loss too.
fixed gear bikes have other losses, especially going down
hill. gravitiational force is resisted by the leg muscles
where the recovered energy is converted into glycogen and
stored for later use on an uphill.
Vik
something similar for recumbent sized tires and the exercise is not trivial.
We can argue theory all we want, but ultimately I'll go with your real world
experimental results as I can't ride a theory.
Cheers,
Vik
thre...@gmail.com
www.vikram-banerjee.com
-----Original Message-----
From: ran...@googlegroups.com [mailto:ran...@googlegroups.com] On Behalf Of
Jan Heine
Sent: May 18, 2007 7:58 AM
To: Haynes, Davy A. (MSFC-EV33); Charles Coldwell
Cc: Don Perley; ran...@googlegroups.com
Subject: [Randon] Re: Brevet tire brand?
Our tests measured all tire-related factors combined - basically, all
we wanted to know which tire was faster than the next. Whether the
reasons were aerodynamic, rolling resistance or bump losses doesn't
matter for a brevet rider.
Jan Heine
Editor
Bicycle Quarterly
140 Lakeside Ave #C
Seattle WA 98122
www.bikequarterly.com
David Buzzee
Tom Worster <f...@thefsb.org> wrote:
Be a better Globetrotter. Get better travel answers from someone who knows.
Yahoo! Answers - Check it out.
Emily O'Brien
> hill. gravitiational force is resisted by the leg muscles
> where the recovered energy is converted into glycogen and
> stored for later use on an uphill.
Hahaha, I like that idea! So riding a fixed gear is like driving a hybrid car, right? Does that mean that if I slow down more on the descents I'll go faster up the climbs? I'd say that's probably not worth the trouble for the moderate hills, but definitely worth it for the steeper ones where the energy stored on the way down will help me go faster and keep my cadence above 15 RPM!
Emily "That's a theory I can get behind!" O'Brien
Don Perley
energy is some from the muscle acting as a spring, but that only works
for one stretch cycle at best.
I didn't think there was any reverse gear on the Kreb cycle.
David Buzzee wrote:
> Sorry, the human body is incapable of converting energy into glycogen as
> it has a limited ability to conduct photosynthesis.
>
Tom Worster
-----Original Message-----
From: David Buzzee <d_bu...@yahoo.com>
Sent: Fri, May 18, 2007 11:04 am
To: Tom Worster <f...@thefsb.org>, Jan Heine <hei...@earthlink.net>
Cc: Haynes,Davy A. (MSFC-EV33) <davy....@nasa.gov>, Charles Coldwell <cold...@gmail.com>, Don Perley <per...@comcast.net>, ran...@googlegroups.com
Subject: Re: [Randon] Re: Brevet tire brand?
Sorry, the human body is incapable of converting energy into glycogen as it has a limited ability to conduct photosynthesis.
Tom Worster <f...@thefsb.org> wrote:
From: Jan Heine Sent: Fri, May 18, 2007 9:57 am
> The numbers I have seen indicate that they are much
> smaller than rolling resistance losses (see below).
that's my understanding too. good quality hub bearings in
good condition and correctly adjusted can be ignored for
these calculations. the freewheel mechanisms will have a
little loss too.
fixed gear bikes have other losses, especially going down
hill. gravitiational force is resisted by the leg muscles
where the recovered energy is converted into glycogen and
stored for later use on an uphill.
---------------------------------
Haynes, Davy A. (MSFC-EV33)
>
>fixed gear bikes have other losses, especially going down
>hill. gravitiational force is resisted by the leg muscles
>where the recovered energy is converted into glycogen and
>stored for later use on an uphill.
>
>
Grins,
Davy
Haynes, Davy A. (MSFC-EV33)
>
>There have been studies that show that cross-chaining does not
>matter. What does matter is cog size - anything below 14 teeth does
>decrease your efficiency quite a bit, but still not in the same order
>of magnitude as tire resistance.
>
Cross chaining does increase friction, although chain losses are
typically low, like 2% for a clean, lubed straight chain. And, yes,
smaller cog sizes increase friction as well due to higher chain
articulation angles.
> From my own experience, replacing a totally shot BB with a brand-new
>one did not improve my speed one bit - to my great disappointment.
>(The BB had developed no bearing races left, just a series of pits.)
>
The additional frictional losses were there, but I don't see how you
could have possibly detected it at such low levels (1%?).
>
>Derailleur drivetrain efficiency is somewhere around 95%. Again, you
>lose very little power there.
Generally true, except for many recumbents, which often have additional
idlers, sometimes in on the driveside, which add noticeable losses.
>
>So if you put out 150 Watt, you lose less than 2% to your bearings,
>and maybe 5% to your drivetrain.
>
I would say that's about right, which means 7% of that 20% quoted
earlier (roughly 1/3) is NOT tire rolling resistance.
>Note that some people differentiate between rolling resistance and
>bump (or suspension) losses. Bump losses is energy that is absorbed
>(mostly in the rider's body) as the bike vibrates or jumps over
>bumps. In that case, rolling resistance becomes only the energy
>absorbed within the tire. However, the two are very closely related,
>so it makes sense to treat them together.
>
And that can be most significant of all given the crappy roads we often
find ourselves on!
Haynes, Davy A. (MSFC-EV33)
>Certainly, frictional losses in the wheel bearings are included in
>rolling resistance. Think about the way rolling resistance is
>measured: you put a rider and bike at the top of an incline of known
>height and see how far he rolls without pedaling after coming off the
>end of it. So the analysis extends to any friction in any part of the
>bicycle that could be moving when you are not pedaling.
>
Actually rolling resistance is best measured by drum testing (although
that's not perfect since the contact patch is not the same shape as for
a flat surface).
Using roll-down tests to examine rolling resistance is poor methodology,
given that what you are attempting to measure is 4 to 6 times less than
the primary force at work, namely aero drag. That [aero drag] is also
somewhat uncontrolled and variable due the environment, i.e. the winds
are never perfectly calm or the same from run to run, and any passing
traffic has a noticable effect as well. Large numbers of repeat runs
(~100) would be necessary to weed out these uncertainty effects and
obtain anything approaching a statistically relevant conclusion of RR.
In practice, this is very difficult to do, since conducting such a large
number of runs for each configuration (tire) would require long
durations of time, over which wind and temperature change, leading to
even more uncertainties.
Davy
Emily O'Brien
> From: David Buzzee <d_bu...@yahoo.com>
> Subject: [Randon] Re: Brevet tire brand?
> Sent: 18 May '07 15:04
>
> Sorry, the human body <snip>
> has a limited ability to conduct photosynthesis.
Some years ago, the Academy of St. Martin in the Field was trying to expand their repertoire to include more works by little-known contemporary composers. The winning submission to their call for original compositions was a very abstract and possibly hallucinogen-induced piece discussing the private lives of green plants. The last movement, according to the composer's notes, required a background in biochemistry and used a musical medium to describe the source of a plant's life energy. Real crunchy-hippy stuff.
The first rehearsal came around, and the orchestra read through the first three movements without a hitch. However, they got to the last movement, and they stopped dead in their tracks. Sir Neville Mariner tried again and again to give a downbeat, but nothing much happened. After many tries and an angry tirade at the viola section, he turned to the composer and said, "How can I conduct this piece? I am trying to be very clear, but it just won't work!" and stomped steaming to the back of the hall.
The composer looked very apologetic, but said, "Here, try this!" and put a potted tree on the podium. The violas started up, and all of the players came in as they were supposed to. Mariner looked dumbfounded, and asked the composer, "Hey, what is this, some kind of joke?"
The composer turned back and said, "I'm sorry, but the human body has a limited ability to conduct "Photosynthesis"......
Emily "Too much time on my hands" O'Brien
Orin
wrote:
> Mark Carry wrote:
> > Mavic Ksyrium's come in several models, some with aluminium spokes
> > (zicral) and others with steel, in varying widths of bladed
> > configurations. The zircal spokes tend to by a very wide blade which
> > could contribute to the 'kiting' you notice but from the Elites on down
> > they are not nearly so wide. The commonality is that they are straight
> > pull rather than being bent at the head which is the point at which many
> > spoke failures occur.
>
> Spokes only fail at the bend if the spoke tension is too low. If your
> wheels are properly built, this simply won't happen.
>
> The Mavic Ksyrium wheels are undoubtedly very good wheels for those
> racers who are supported or those riders who can afford to replace
> wheels every couple thousand miles, particularly if the rider in
> question is the typical 145lb Cat 2 type.
>
> I feel sorry for the big 200 lb guys who've been sold these "ultralight"
> wheels, thinking that they'll climb hills faster having saved a few
> dozen grams. Of course they don't climb any faster, but their wallet is
> certainly lighter.
Ksyrium Elites (mentioned in this thread) are expensive and anything
but light wheels that are cashing in on the marketing success of the
Ksyrium name. So whereas I still think these are inappropriate
randonneuring wheels, it certainly isn't due to being "ultralight"...
Orin.
Jim Bronson
How about reflective sidewalls?
mbiswell
Noted/suggest wait until a sale - but it doesn't sound like you are doing
that anyways. :-)
But also Ksyriums are not typically failing at 1,400 miles of use, and they
are not too weak for a 170lbs rider as Peter JW hyperbolized yesterday, (for
his own reasons?).
And, Peter, spokes do fail. They do, Man - and it's not all about the
wheelbuilder, that's for sure.
Regards!
jake Kassen
> Here's another thought for brevet tires.
>
> How about reflective sidewalls?
More reflectiveness on the bike can never hurt but I've found that the
reflective sidewalls get covered with brake dust and road grit so fast
as to completely block out the reflective material.
I've heard the suggestion to cover 1/3 of the rim with reflective tape
to give a "flash" every revolution of the wheel. I've also seen people
cover their spokes with reflective tape which looks neat if anything
else. The one good thing that can be said about wide bladed spokes is
that you can put a lot of reflective tape on the wheel.
The trick is coming up with a pattern of colored reflective tape to put
on the spokes so that a picture is shown when the wheel is turning at
the right speed. Now that would make someone a true bike geek.
Jake "Now see this" Kassen
Orin
> Noted/suggest wait until a sale - but it doesn't sound like you are doing
> that anyways. :-)
650Cs were going for $200 A PAIR at the end of last year! Even at
that price, I wouldn't bother.
> And, Peter, spokes do fail. They do, Man - and it's not all about the
> wheelbuilder, that's for sure.
True. I had a spoke fail in my rear wheel a couple of years back.
POINK! "I wonder what that was? Oh, I broke a spoke." I just rode
home without even having to adjust the brake and replaced the spoke at
my leisure. 32 spoke wheel.
A big problem with the low spoke count wheels is that as PJW says,
they are fine for "racers who are supported", but hit something hard,
break a spoke or have one come loose and there is nothing you can do
at the side of the road. Happened a few weeks back when a rider
touched the wheel in front and went down. Slightly bent front wheel.
Lightweight, paired spoke, not possible to true. One rider limping
home with rubbing front wheel. It would have been trivial with a
traditional wheel to true it up sufficiently to continue the ride.
Orin.
David Buzzee
Tom Worster <f...@thefsb.org> wrote:
surely you're pulling my leg, david?
-----Original Message-----
From: David Buzzee
Sent: Fri, May 18, 2007 11:04 am
To: Tom Worster , Jan Heine
Cc: Haynes,Davy A. (MSFC-EV33) , Charles Coldwell , Don Perley , ran...@googlegroups.com
Subject: Re: [Randon] Re: Brevet tire brand?
Sorry, the human body is incapable of converting energy into glycogen as it has a limited ability to conduct photosynthesis.
Tom Worster wrote:
From: Jan Heine Sent: Fri, May 18, 2007 9:57 am
> The numbers I have seen indicate that they are much
> smaller than rolling resistance losses (see below).
that's my understanding too. good quality hub bearings in
good condition and correctly adjusted can be ignored for
these calculations. the freewheel mechanisms will have a
little loss too.
fixed gear bikes have other losses, especially going down
hill. gravitiational force is resisted by the leg muscles
where the recovered energy is converted into glycogen and
stored for later use on an uphill.
Looking for a deal? Find great prices on flights and hotels with Yahoo! FareChase.
Joe Gross
>
> How about reflective sidewalls?
>
> http://www.panaracer.com/eng/products/road/race.html#h
Don't bother. They limit your tire choices and aren't that bright.
Get reflective tabs for your rims. They'll be brighter and are visible
from a larger angle. On the Davis 600k I was told that my wheels were
two distinct white hoops from over a half mile away even from nearly
directly behind.
http://img.stimpy.net/pics/bike/davis600k-2007/640x480/IMG_5273.JPG.html
I picked up some high intensity tape at
http://www.identi-tape.com/hi-intensity.htm and applied 1.5" tabs to
my rims between every other spoke.
I also put some red strips on the back of my helmet and rack or seat
stays, depending on bike. It's very effective.
http://img.stimpy.net/pics/bike/davis400k-2007/640x480/IMG_5264.JPG.html
Joe
Joe Gross
>
> The trick is coming up with a pattern of colored reflective tape to put
> on the spokes so that a picture is shown when the wheel is turning at
> the right speed. Now that would make someone a true bike geek.
Been done.
http://www.instructables.com/id/EQ8CBZBN7DEP286MR8/
I've seen these "live" and they're really awesome.
Joe
Steve Palincsar
> A big problem with the low spoke count wheels is that as PJW says,
> they are fine for "racers who are supported", but hit something hard,
> break a spoke or have one come loose and there is nothing you can do
> at the side of the road. Happened a few weeks back when a rider
> touched the wheel in front and went down. Slightly bent front wheel.
> Lightweight, paired spoke, not possible to true. One rider limping
> home with rubbing front wheel. It would have been trivial with a
> traditional wheel to true it up sufficiently to continue the ride.
I saw the same on the Lancaster County PA Covered Bridges Metric last
year. One broken spoke, and his wheel wouldn't turn at all. People
come a long way to do that ride, and what for a traditional wheel would
have been a non-event turned into a DNF and a ride in the sag wagon for
that guy.
Same happened to a woman on a club ride I was on a couple of years ago.
The closest bike shop was at least 10 miles away, nothing at all in
the town we were in but a gas station and a country store, and her wheel
wouldn't turn at all. Jammed in the fork. It wasn't one of the
expensive aftermarket ones, either: this one came on the bike, and it
was pretty much just above entry level - a 105 equipped bike. We
eventually had to leave her, as there simply was nothing to be done. I
guess somebody came back with a car for her - at least I hope so.
And one guy back in 2002 or so, with a really expensive set of boutique
Campy-compatible wheels had the freehub body lock up 100 yards out of
the parking lot on a different club's ride. His wheels had to go back
to the factory, and it took him around six weeks to get a replacement.
The shop had to lend him a bike for a while - evidently Campy-compatible
boutique wheels are pretty scarce - so he was riding an ill-fitting
borrowed low-end Litespeed aluminum loaner rather than his top of the
line bike for over a month. Any "normal" wheel, he'd have been back on
the road in a couple of hours, a simple repair any shop could have done,
even though it was a far more serious failure than simply a broken spoke.
So you don't have to be doing thousand-kilometer brevets to end up
geting seriously screwed by such wheels. Even ordinary riders doing
ordinary weekend rides come to grief (or, at least, to disappointment
and inconvenience).
--
Steve Palincsar
pali...@his.com
Alexandria, VA, USA
Steve Palincsar
> Well, I am as 'green' as most bicycle riders but I still can't convert
> energy into matter. If I could it indeed would give me a leg up on
> other riders, wouldn't it?
Of course you can. You take in energy (calories) and convert it to body
fat, don't you?
;-)
Orin
> At 1:38 PM -0400 5/17/07, Don Perley wrote:
>
> >A rule of thumb I had been using, gotten from a Scientific American
> >article maybe 3 decades ago, was that an average racing bike going
> >steady 20 mph on a flat, smooth, windless road used 98% of the power
> >on wind resistance, and 2% on everything else (rolling resistance,
> >bearings, chain, idler pulleys, etc). Some deviation could be
> >attributed to rider size, measurement technique etc, your postings
> >indicate they were low on the mechanical losses by well over an
> >order of magnitude. That has to raise questions of how you measured
> >the Crr so I can understand that vast difference.
>
> 98% wind resistance is not correct for 20 mph.
>
> When you go to analyticcycling.com and reduce the rolling resistance
> to 0 (make sure you also reduce the slope to 0), you find you need a
> power output of only 108 Watt to go 8.9 m/s (20 mph). All you
> overcome now is wind resistance. At 20 mph, that takes 108 Watt.
>
> When you add rolling resistance - by putting in a good racing tire
> Crr of 0.005, you need 141Watt to attain the same speed. Putting in a
> "sturdy" tire, but not the worst we tested (Crr=0.01), you need 173
> Watt.
>
> Thus, at 20 mph, rolling resistance (bearings, tires, etc.) makes up
> between 33 Watt (141-108) and 65 Watt (173-141), or between 23% and
> 38% of the overall resistance.
I think your CdA is too low. It takes roughly 200W to do 20 mph on my
Rambouillet with hands on hoods, normal clothing, fenders, Grand Bois
Cypres 700Cs and carradice bag. About the same when I was running
Michelin HiLite SuperComps in 700x23.
> That still means that 62% to 77% of your overall resistance is due to
> aerodynamic drag, but the problem is that you can't do much about
> your air resistance. Aero wheels improve the aerodynamics of the
> bike/rider by about 2%. (Most ad claims are based on the improvements
> compared to non-aero wheels, tested alone, without bike and rider...)
>
> Even a full track pursuit setup (disc wheels, aero frame, aerobars,
> skinsuit, aero helmet) is only 10-15% more aerodynamic than a weekend
> rider on the hoods. So the best most riders can hope for is
> decreasing their overall resistance by up to 5% with various
> aerodynamic improvements, unless you go with a fully-faired recumbent.
Not relevant to PBP, but from experience aero-bars alone are worth 1
to 1.5 mph at 20 mph.
I have a Cervelo Dual TT bike. I found it easier to ride at the front
of a paceline in the aero position at 22 mph than at the back at the
same speed, hands on the cow-horns. Other riders in my group hated it
when I showed up with the Cervelo as I was so much faster on the flat!
Twenty years ago, when I was racing, my best 10 mile TT speed was
about 24 mph. A couple of years ago, nowhere near as fit, I did 23.8
mph on the Cervelo for 11.5 miles.
So IMO, aero can count for much more than 10-15% difference in
resistance. I suppose I need to wire up a power meter on the Cervelo
now...
> Rolling resistance, on the other hand, can vary by more than 100%. So
> if you cut your rolling resistance in half, you can reduce your
> overall resistance between 11 and 19%.
I wish you'd tested Ruffy-Tuffys. Along with the Specialized
Armadillo, one of the harshest, slowest tires I've ridden. It would
have been interesting to see the results, though extrapolating from
the other Rivendell results, I'd expect it to be slower than the Rolly-
Polly by a second or so.
Orin.
gazer
http://static.instructables.com/deriv/F21/8SG5/L35EP27YU4U/F218SG5L35EP27YU4U.SMALL.jpg
It is amazing how people react to these lights. They're so stumped
that they forget that they're supposed to be aiming their cars at you.
-jk
Dave Cramer
bike potions tell us we can't possibly ride more than two or three
miles while ingesting simple sugars...
:)
Dave "chocolate milk and chocolate croissants" Cramer
Don Perley
> The trick is coming up with a pattern of colored reflective tape to put
> on the spokes so that a picture is shown when the wheel is turning at
> the right speed. Now that would make someone a true bike geek.
If you have black anodized wheels, there is black reflective tape that's
a pretty neat effect.
Haynes, Davy A. (MSFC-EV33)
>So IMO, aero can count for much more than 10-15% difference in
>resistance. I suppose I need to wire up a power meter on the Cervelo
>now...
>
That's right. Unless you are climbing, it's all about the aero. If you
want to go 10% faster, get lower. Changing tire brands will not get you
there, unless you go from a knobby to a slick.
Davy
Emily O'Brien
They are pretty cool though. I keep meaning to put them back onto my commuter bike, which I'm in the process of loudly decorating with colorful reflective tape.
Emily "Reflective fake lugs" O'Brien
Haynes, Davy A. (MSFC-EV33)
>Actual rolling resistance is meaningless for actual riders, as we
>care about the overall tire-related resistance.
>
Huh? Rolling resistance is a common engineering term, but I've not
previously heard of "overall tire-related resistance." Please explain
the diffference.
>
>This was hashed out on rec.bicycles.tech a few months ago. The
>current issue of Bicycle Quarterly includes an error analysis of our
>tests. Basically, the explained variability (due to different tires)
>was much greater than the unexplained variability (due to external
>variables). If our very consistent results were just the result of
>"luck," then there would be a less than 1: 10,000 chance that the
>results would come out that way. (My co-author has a minor in
>statistics, so that helps!)
I am surprised you have such repeatability. I would be interested in
seeing your raw data as well as understading your test techniques. You
must have a trick or two that I've not heard of before. Are these
relatively low speed tests? I could see that working, particularly if
you had a facility where you could do that indoors.
>
>As a result, we are quite confident that we were able to control the
>variables through careful design of the experiments.
>
You are fortunate to have such an excellent test locale where you can
control such variables as weather. Did you do this indoors?
I am intrigued. Please tell me more.
Davy
Joe Gross
I had these (identi-tape sells 'em) for a while and found they were
only about 10% (at most) as bright as the white tape. I did like that
it was nearly invisible in the daytime.
http://img.stimpy.net/pics/bike/davisdouble2004/640x480/IMG_0117.JPG.html
While they're better than nothing I recommend using the white tabs. If
you want to avoid putting white tabs on your non-silver rims you can
add just 2-4 on your rims will still be very visible when the bike is
rolling.
Joe
Pam Wright
Joe Gross <jgr...@stimpy.net> wrote:
Food fight? Enjoy some healthy debate
in the Yahoo! Answers Food & Drink Q&A.
Peter Jon White
> Jim Bronson wrote:
>> Here's another thought for brevet tires.
>>
>> How about reflective sidewalls?
>
> More reflectiveness on the bike can never hurt but I've found that the
> reflective sidewalls get covered with brake dust and road grit so fast
> as to completely block out the reflective material.
>
But that's pretty easy to clean. Thirty seconds per tire with a wet rag.
And there's not all that much difference between the grime that builds
up on the tires and the grime that builds up everywhere else on the
bike. So if reflective tire sidewalls aren't useful, nothing else on the
bike is going to benefit from having reflective tape applied to it.
--
Peter Jon White
Peter White Cycles
24 Hall Rd.
Hillsborough, NH 03244
603 478 0900 Phone
603 478 0902 Phax
www.PeterWhiteCycles.com
Peter Jon White
>
> Don't bother. They limit your tire choices and aren't that bright.
>
> Get reflective tabs for your rims. They'll be brighter and are visible
> from a larger angle.
The two are rather different. Reflective tire sidewalls will be mostly
visible from the side, where reflective tape on many rims will be
invisible. Of course that's not the case with V section rims.
Reflective tape on rims may be visible from the side, as with the V
section rims, but mostly it will be visible from front and rear, off
just a bit to the side, of course.
So I don't see this as an either/or choice. I can't think of any reason
why a night cyclist would not want to use a reflective sidewall on a
tire. It can only help.
Emily O'Brien
But fenders make a great surface for decorating with reflective tape.
Emily
> -------Original Message-------
> From: Peter Jon White <li...@peterwhitecycles.com>
> Subject: [Randon] Re: ***POSSIBLE SPAM*** [Randon] Re: Brevet tire brand?
> Sent: 18 May '07 20:55
>
>
> jake Kassen wrote:
> > Jim Bronson wrote:
> >> Here's another thought for brevet tires.
> >>
> >> How about reflective sidewalls?
> >
> > More reflectiveness on the bike can never hurt but I've found that the
> > reflective sidewalls get covered with brake dust and road grit so fast
> > as to completely block out the reflective material.
> >
>
> But that's pretty easy to clean. Thirty seconds per tire with a wet rag.
> And there's not all that much difference between the grime that builds
> up on the tires and the grime that builds up everywhere else on the
> bike. So if reflective tire sidewalls aren't useful, nothing else on the
> bike is going to benefit from having reflective tape applied to it.
>
Peter Jon White
> Yeah, but when you ride in the rain, tires are uniquely positioned to
> accumulate dirt and brake dust. They're right next to the braking
> surface to the outside, where all the water and brake dust goes when
> the wheel spins. Compare the visibility of that reflective stripe on
> your tires with the visibility of a reflective strip anywhere else on
> the bike, and see which one gets obsucred by crud sooner, even if you
> don't use fenders! But fenders make a great surface for decorating
> with reflective tape.
>
> Emily
All true. My point is that since it's so quick and easy to clean, and
since a reflective sidewall does add to a bike's visibility, there's no
reason to pooh pooh them. And just because reflective tape on a fender
doesn't get dirty as quickly as a tire sidewall, if you don't clean the
tape on the fender, it will eventually get to the point where it does
you little good as well. You're going to want to keep the reflective
tape on your fender clean too. So why not clean the tire sidewall at the
same time, and have the added safety of a reflective sidewall?
John McClellan
other riders' bikes at night, regardless of conditions. My finisher's
photo from BMB 2004, taken in the wee hours, is overridden with the
reflective glare from my sidewalls. And there was enough rain, crud,
stray animals and general road detritus accumulated on that little
ride to last a lifetime! As Peter points out, reflective material
isn't an either/or choice. I also use those velcro tabs that
Rivendell sells on my wheels. More is more...and safer.
Robert Magyar
As a driver, unless you have reflectors in the spokes, the Rivendell reflective tab that you can velcro in the spokes is the best thing that tells me a bicycle is crossing in front of me.
As a driver, the Rivendell reflective ankle tabs are the one thing I would see that tells me a bicycle is in front of me, they are far better than other brands I have seen and have more square inches of reflective material.
Bob
> From: john-mc...@att.net
> To: ran...@googlegroups.com
> Subject: [Randon] Re: ***POSSIBLE SPAM*** [Randon] Re: Brevet tire brand?
Peter Jon White
>
> Noted/suggest wait until a sale - but it doesn't sound like you are doing
> that anyways. :-)
>
> But also Ksyriums are not typically failing at 1,400 miles of use, and they
> are not too weak for a 170lbs rider as Peter JW hyperbolized yesterday, (for
> his own reasons?).
>
> And, Peter, spokes do fail. They do, Man - and it's not all about the
> wheelbuilder, that's for sure.
>
>
> Regards!
>
>
>
> From: Orin
> Sent: Friday, May 18, 2007 9:46 AM
>
>> Spokes only fail at the bend if the spoke tension is too low. If your
>> wheels are properly built, this simply won't happen.
>>
>> The Mavic Ksyrium wheels are undoubtedly very good wheels for those
>> racers who are supported or those riders who can afford to replace
>> wheels every couple thousand miles, particularly if the rider in
>> question is the typical 145lb Cat 2 type.
>>
>> I feel sorry for the big 200 lb guys who've been sold these "ultralight"
>> wheels, thinking that they'll climb hills faster having saved a few
>> dozen grams. Of course they don't climb any faster, but their wallet is
>> certainly lighter.
I don't recall hyperbolizing anything regarding 170lb riders and Ksyrium
wheels. Could you please elaborate?
Don Perley
> "Overall tire related resistance" is everything that changes when you
> change tires. For example, if you go from a "sturdy" 700C x 32 mm
> tire to a "supple" 700C x 25 mm tire, you will change the
> aerodynamics (narrower tire has less frontal area), you will change
> the rolling resistance (in the strict engineering term) and you will
> change the bump losses. Also the weight of the tire. For a
> randonneur, it doesn't matter which of these change how much, but
> they are interested in the overall sum - which tire is faster. That
> is what we measured.
>
> Of course, trends we observe in our data then allows us to draw
> comparisons, for example, tires with supple sidewalls seem to roll
> faster, and so do wider ones, etc.
If you are determining "overall tire resistance" by a coastdown, then,
all else equal, a heavier tire will test as faster (as would a heavier
rim or anything else on the bike), when in fact, it would be pretty
neutral on flat steady riding, and a detriment for uphill or
acceleration. It will also exaggerate any rolling resistance advantage
that a wider (and heavier) tire might actually have.