700/23 vs 700/25 tires ?

On Fri, 30 Jan 2009 21:20:14 -0800 (PST), Frank Krygowski
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.

On Sat, 31 Jan 2009 04:13:47 GMT, Ryan Cousineau
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.

wrote:

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

On Sat, 31 Jan 2009 21:52:45 -0000, "Pete Biggs"
t wrote:

wrote:

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

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

In article ,
Phil W Lee phil(at)lee-family(dot)me(dot)uk wrote:

Ryan Cousineau considered Sat, 31 Jan 2009
04:37:10 GMT the perfect time to write:

In article ,
Phil W Lee phil(at)lee-family(dot)me(dot)uk wrote:

Ryan Cousineau considered Sat, 31 Jan 2009
00:40:19 GMT the perfect time to write:

In article ,
wrote:

On Fri, 30 Jan 2009 19:49:09 -0000, "Clive George"
wrote:

"Chalo" wrote in message
.
..

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.

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?

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.

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 he

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.

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.

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

On Sat, 31 Jan 2009 21:45:35 GMT, John Forrest Tomlinson
wrote:

On Fri, 30 Jan 2009 21:20:14 -0800 (PST), Frank Krygowski
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.

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

John Forrest Tomlinson wrote:

Chalo wrote

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?

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

On Sat, 31 Jan 2009 16:46:16 -0800 (PST), Chalo
wrote:

Because they _think_ that's the fastest option. Instrumented rollers
suggest that a wider tire than racers use would be faster.

Not quite right: instrumented rollers suggest that a wider tire has
less rolling resistance. But that's only one part of the equation of
what makes something fast.

The wind
tunnel suggests that lenticular disc wheels with knife edges would be
faster.

I'm not sure what you mean by knife edges.

On Feb 1, 12:46*am, Chalo wrote:
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?

Yes, they were, at that time, considering their equipment, their event
and themselves.

On Sat, 31 Jan 2009 17:44:58 -0700, wrote:

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.

I said it can be affected by details. You've repeatly said that
because something has a tiny or extremley difficult to measure effect
it has no effect.

And you're repeatedly refused to answer simple questions I've asked
you whereas I've answered many of yours.

Cluck cluck cluck