Re: [CR] Wider = faster

(Example: Racing:Roger de Vlaeminck)

From: "Dave Porter" <frogeye@porterscustom.com>
To: "'Jan Heine'" <heine94@earthlink.net>, <classicrendezvous@bikelist.org>
References: <a062408a0c9709b20b898@[67.101.5.160]>
Date: Thu, 3 Feb 2011 12:20:47 -0700
Thread-Index: AcvDzR4OM4WNOPVbTtCZXMOjwvmclwACg0fg
In-Reply-To:
Subject: Re: [CR] Wider = faster


http://www.bikeradar.com/Road/news/article/cervelo-testteam-get-testing-in-b elgium-25190

Cervelo testing, narrow pave tire. Seems the folks at Vittoria have some other/new ideas? DaveP

frogeye@porterscustom.com

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-----Original Message----- From: Jan Heine [mailto:heine94@earthlink.net] Sent: Thursday, February 03, 2011 11:05 AM To: classicrendezvous@bikelist.org Subject: Re: [CR] Wider = faster
>I think all the studies have shown that the aerodynamic resistance
>increases somewhere around 20 MPH so that the wider tire loses that
>roll fast advantage.

We tested different tire width in the wind tunnel, and found that the differences in wind resistance between a 25 and a 32 mm tire were lost in the noise.

The rolling resistance differences between different-width tires are significant, but they depend very much on the road surface. The rougher the road, the wider a tire is ideal. So any generalized statements on which tire is fastest is misleading. There appears to be little doubt that all things considered, a 25 mm tire is faster than a 23 mm tire on average roads, even at racing speeds. When you draft in a peloton, the aerodynamic issues are greatly reduced, anyhow, so you can ride an even wider tire. (If you are a break-away specialist, you are more concerned about aerodynamics...)

On cobblestones, a 38 mm tire will be much faster than a 25 mm tire - we tested this, too, when we measured suspension losses.

A couple of years back, Chuck Schmidt posted a report to the iBob list indicating many track riders now use 23-24 mmm tires... see

http://search.bikelist.org/getmsg.asp?Filename=internet-bob.10801.1487.eml

For a track bike, 24 mm probably does qualify at "fat."

Jan Heine Editor Bicycle Quarterly 2116 Western Ave. Seattle WA 98121 http://www.bikequarterly.com

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