Wider tires have greater rolling resistance all things being equal. My bad for not defining "larger". I meant larger in diameter--not tread width. I'm a bit sensitive to Wikipedia because there are some topics where people change them every day depending upon their leanings. Sorry about that. That's the way I understand it. There are a lot of variables. The issue I had was with "the tire rubber is deformed more with higher vehicle weight". My assumption is that as vehicle weight increases tires with greater carrying capacity are installed. - - - Updated - - - That wasn't what I was thinking. I was thinking vehicle size increase = tires with more carrying capacity. If we're talking about the same vehicle with the same tires, then you are supposed to increase pressure to compensate for the weight. This will increase the pressure on the rubber but it won't increase the rolling resistance. If you don't increase the tire pressure than, of course rolling resistance will go up. And that's actually a pretty good paper. But I believe the basic problem here was my reading of the original post. Sorry about that. - - - Updated - - - Something to think about though is this rolling resistance table. It's a bit out of date because tire manufacturers don't like to give out rolling resistance information but it does have the numbers for a variety of real tires. One of the interesting points is that one of the lower rolling resistance value tires is the 40 lb. Michelin Diamairs 285/60R18 with a value of 0.00889 and an overall diameter of ~31". One of the highest rolling resistance tires is the 10 lb. BFG Turanza LS-T P205/65R15 with a value of 0.01200 and an overall diameter of ~25.5". Now there's no doubt that the 18" tire will actually use more fuel, especially in the city, because it's a lot more mass to get going, but the rolling resistance part is actually smaller.