Any scientific research on tyre width?

less contact with road means less friction, which translates to less power output...

i also think that there will be less weight on the tire itself (even though it may be minimal), which should translate into a slight output gain...

but, that's me just thinking out loud...

Yes, over on SlowTwitch there was a fairly recent study.

I have no scientific research but I can tell you that when I go from my road bike (23) to my hybrid (28), the tires on the hybrid feel "sticky" on the road - I can definitely feel the increased resistance.

There is a guy who tests a bunch of tires for rolling resistence numbers from all sorts of manufacturers and sizes in both tubular and clincher.  He then brokes out how much power it takes to move them a certain unit.

So yes, there is some scientific research behind it (aside from the obvious - bigger contact patch = more friction as stated above).

Wasn't there something about decreased profile and decreased yaw with a skinnier tire as well?

John

If I remember right, there was also a point of diminished return if you had to pump the smaller tire up too hard to absorb the irregularities in the road. Too rough a ride soaks up some power too, but in general a smaller tire will provide less resistance. I also think getting the tire pressure right becomes more of a problem for bigger riders who may need a bit more tire to cut down on flats.

It's more complicated than that...

I think one of the tri magazine did a research study on this a while back...

Here is a summary (by a tire manufacturer)

http://www.schwalbetires.com/tech_info/rolling_resistance