"GRL" wrote in message
...
Does it not make sense that the fatter tire will have more rolling
resistance because the contact patch (and thus friction) will be greater
with the fatter tire?


Not necessarily. At a given tire pressure and weight, the contact patch is
*the same size*, no matter how wide (up to a point). Think PSI. Pounds per
sq inch.
A 200lb rider/bike creates a 2 sq in patch for a bike tire pumped to 100
psi. No matter what the width or diameter.

The contact patch will be a different shape for a wider vs skinnier tire.
Wide and short, instead of long and skinny. Less sidewall deformation as the
tire rolls.

This is, of course, making the huge assumption that all other factors are
equal (Tire construction, TPI , pressure, etc).

Width (wind resistance) may overcome the difference in Crr.

If you look at vehicles built for straight-line speed
(other than those where massive power needs to be transmitted to the
ground - definitely NOT bikes) be it soap-box racers to land speed record
assault rocket cars, the tires are hard and skinny to minimize rolling
resistance.

They are also skinny to minimise frontal area/wind resistance. Those types
of vehicles also do not have to worry about wear, traction in varying
conditions, marketing costs, etc.

Several tire rr tests have been done in the recumbent community.
http://www.beezodogsplace.com/Pages/...Resistance.pdf
http://www.legslarry.beerdrinkers.co.uk/tech/GS.htm

Pete