I can see both sides of the coin. One skinnier tires are easier to pedal fat tires takes a little more effort. If going long distance over 5 miles I would rather have smaller tires bad roads or not on my mtn bike turned commuter. I run the skinny pan racer pro v 26x1.50 I also have fatties to 26x 2.25 I run on my mongoose mtn bike. I can really tell a big difference in them like nite and day. On the skinnier wheel I dont half to exert much power to keep 12 mph. On the fat tires I exert double if not triple the power to get to the same speed .plus skinnier tires make the bike very responsive the fatter the tire it seems more sluggish to me .