Re: [CR]650B the perfect wheel size?

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In-Reply-To: <a0521068fbbbd7d5e7685@[66.167.252.130]>
References: <NPEDLCGAOOGCMLKPMGOGGEPPCHAA.jim-kerr@comcast.net>
Date: Thu, 23 Oct 2003 15:01:51 -0400
To: Jan Heine <heine93@earthlink.net>, classicrendezvous@bikelist.org
From: "Sheldon Brown" <CaptBike@sheldonbrown.com>
Subject: Re: [CR]650B the perfect wheel size?


At 5:58 AM -0700 10/23/03, Jan Heine wrote:
>650B is considered superior for non-racing by many, for good reason:
>They are bigger than 26", so the bike handles like a "real" bike,
>but small enough to make a very strong wheel. 700C wheels on a
>touring bike or a tandem really are not the brightest idea, except
>that they are easy to sell, and parts are easy to procure. (I, too,
>have several tandems and touring bikes with 700C wheels, and I know
>that they can work fine.)
>
>My experience with 26" is somewhat limited (a Bridgestone XO-2, a
>few tandems, all of which are off-topic, I know!), but based on
>that, I very much prefer 650B over 26" and smaller sizes (an
>even-more off-topic, even worse Bike Friday). And with the current
>state of repair of the roads in Seattle, which is not too different
>of that in Europe after World War II (they had tanks grinding them
>to bits, we have SUVs and studded tires), I am seriously considering
>switching to 650B on my performance bike. The ability to glide over
>potholes and bumps is amazing. Yet we found during Paris-Brest-Paris
>that the speed of our tandem (rolling downhill side by side with
>other tandems with 700C wheels) was not inferior. (I know that
>roll-down tests are affected by many factors, but it was surprising
>that a several teams of two short, stocky men on 700C tandems rolled
>downhill slower than our 650B bike with two relative tall,
>relatively skinny people. While the handlebar bag may have helped us
>aerodynamically, I deduct that the tires didn't slow us down...)
>
>By the way, I am not sure whether there is a "critical threshold"
>between the tire sizes of 26" and 650B (as a very experienced tandem
>team from Boston with lots of experience with both sizes once
>claimed), which makes one handle great, and the other mediocre at
>best, or whether it is that all 26" bikes I have tried were poorly
>designed. It may well be that great bikes can be built with 26"
>wheels... and I just haven't ridden them. (And I think 26" wheels
>existed in Britain on lightweight bikes during the CR timeline, but
>I gladly stand to be corrected on this.)

Your use of the term "26 inch" is vague and confusing. "26 inch" is not a single size--there are at least _6_different_ "26 inch" sizes, including all 3 of the "650" sizes! 650B is actually in the middle of the range, with other "26 inch" sizes being larger or smaller.

It is better to use the ISO size designations, which are not ambiguous. "650B" is 584 mm. The decimal "26 inch" size used on mountain bikes is 559 mm (the smallest "26 inch") size. The 559 size goes back to the 1930s in the U.S., but was not common in the U.K. before the advent of the mountain bike.

English lightweights generally used the 590 mm (26 x 1 3/8"/650A) size for the more utilitarian models, and 597 mm (26 x 1 1/4") for sportier models, such as "club" bikes.

I know this is a bit confusing, if you want the straight skinny on tire sizing, see my article http://sheldonbrown.com/tire-sizing.html

Sheldon "ISO/E.T.R.T.O." Brown +---------------------------------------------+ | The nice thing about standards is that | | there are so many of them to choose from. | | --Andrew S. Tanenbaum | +---------------------------------------------+ --
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