At 10:00 PM -0500 12/1/09, John Betmanis wrote:
>That's interesting. Not really hijacking this thread, but not
>answering the original question either, has anybody been following
>Jan's writings in Bicycle Quarterly about wider tires being faster
>and requiring less power? Clearly, his numbers aren't lying, but I
>still find it hard to believe. Back in my youth I went from riding a
>gaspipe Hercules with 26" x 1-3/8" tires to a Claud Butler with 27"
>x 1-1/4" high pressure tires and it definitely went faster. Granted,
>the Claud was almost 10 pounds lighter, but would it have been
>faster still with 26" x 1-3/8" roadster tires? Has anyone else
>experienced fat tires being faster than skinny ones?
Of course, the Butler was faster. It had a more flexible frame, which is easier to pedal. You probably were more aerodynamic, too. And the bike was lighter (which is the least important part of the equation).
Also, wider tires are faster only if they have similarly supple sidewalls and a similarly thin tread. So a 25 mm Michelin Pro2 Race is faster than a 20 mm Pro2 Race, a 28 mm Clement Campionato del Mondo is faster than a 21.5 mm Clement Criterium, but a 32 mm Schwalbe Marathon is slower than all of them.
Basically, tire construction trumps width. So the tires on your Hercules may well have been slower than those on your Butler, but not because they were wider.
You can also listen to Georgena Terry's podcast, where she interviewed me on this subject. Click here
Jan Heine
Editor
Bicycle Quarterly
2116 Western Ave.
Seattle WA 98121
http://www.vintagebicyclepress.com