I talked to a guy today with a GMC lowered with a 3/4 Belltech kit and running a set of 20's. I asked him how he liked the belltech kit, he said he was really happy with it. But then he made a comment about only getting about 12 MPG since he put the 20's on. I asked him if they were that much heavier than the stock wheels and tires, he said he didn't think they weighed any more since the 20's were aluminum. He thought because the tires he went with were so much wider than stock that they were causing the lose in fuel economy. Has anyone else noticed that much of a difference when moving up to 20's?

Thanks

 

Well, depending on what size tire he was running before, it can make a difference. 20" wheels are harder to move then the smaller wheels, so he has that going against him (just like it is harder to brake with larger wheels).

Also if the overall diameter is greater than his stock tires, his speedo may be off if he didnt get it re-calibrated, but its probably not enough to cause a huge difference.