From: tomk@netcom.com (Thomas H. Kunich)
Subject: Re: Team Motorola will Race on Clinchers in 1993
Organization: Netcom - Online Communication Services (408 241-9760 guest)
Date: Wed, 6 Jan 1993 23:19:18 GMT

In article <1993Jan6.225208.27344@netcom.com> marquis@netcom.com (Roger Marquis) writes:

>I don't think it has as much to do with the shape of the cross section
>as the amount of casing which can deform to absorb shock.  If you're
>comparing 28c d'Allesandros at low pressure this sounds logical.

The Allesandros and the Michelins have about the same size casing. Yet
they feel amazingly similar. And different to the Continentals.

>I tried Vittoria clinchers when they first came out a few years ago
>and found them to be very unreliable.

My point. Cotton doesn't have the puncture resistance of modern materials.
The puncture resistance of expensive cotton sewups is almost entirely
due to the latex tubes.
>
>Huh?  Avocet is not a company best known for reliable products.

Being a reliable company is _not_ the same thing as having reliable
products. Avocet speedos fail all of the time. The company simply
replaces them. No Big Deal.

>This is a good theory but how do you explain the general consensus that 
>there _is_ a difference.  Personally, I think it becomes noticable when 
>you ride hard and long.  If you're just putting around town you might not 
>notice any difference at all.

General consensus is not fact. It was general consensus that there was
witches in Salem.

I put in 6,000 miles last year. That may be small time to some people
but I think it's more than most put in. How many miles do you figure ut
takes before you develop this magical gift to tell traction?

BTW, I have held professional motorcycle road racing licenses for here
and on the World circuit. I raced off-road and on. I held a professional
racing mechanics license and was in on the development of the Yamaha
350 road racer back in the 60's. I do know something about traction.

>My favorite way of measuring the traction of a tire is _uphill_.  
>That's right, uphill.  Wait for a good wet day and find a steep road 
>with those tar patches running across to fill up the asphalt cracks.  
>Riding up over those steep tar patches you'll get a good idea of how 
>much force is required to break a tire loose without risking lost skin.

All this will tell you is that you have lost traction or not. It tells 
you nothing at all about the traction of the tire versus other tires
under the same conditions.

Believe me, you can only tell the broadest, most gross differences
by feel. There is no way that you are going to tell the difference of
a couple of percent between the most tractive, and the least, compounds
used in tire surfaces. The other variables are too great.

As a racing mechanic I listened in on many conversations of top riders
that would all agree about something that was entirely false. Typically
they wouldn't understand the difference between torque and horsepower,
rake, trail and it's effects on handling, and even things as self
explanitory as _gearing_! To suggest that they could tell the difference
between two similar tires made by difference manufacturers is getting
pretty farfetched. Most the time we would make changes according to the
stop watch not the riders impressions.

An anecdote on this lines: Harley-Davidson rider Cal Rayborn was the
greatest motorcycle road racer that the U.S. ever developed. While
testing some new frames he came in and claimed that one frame was a
piece of s__t. It wobbled, wriggled and more or less frightened him to
death. It was then pointed out to him that he was lapping 20 seconds
a lap faster on that frame. That was the one he used after that.

Newsgroups: rec.bicycles.racing