If you do some deep research, you will find that wider tires will typically have less rolling resistance. And going to a wider tire doesnt increase the contact patch but only changes the shape of the contact patch (if tire pressures remain the same as before).
It gets complicated but simple answer is a wider tire alone wont hurt fuel mileage. Wheel weight and tire compound/tread design have a bigger impact.
Go to autospeed.com and lookup an article called "tyres, grip, and all that..." <- explains everything. Haha.
Last edited by Levi05; 03-05-2013 at 06:33 PM.
Reason: better word choice