The tires are 25.3" diameter 14/70s. Slightly taller than the 13/80s that I replaced. The engine seems to be happy running 1:1 at 3000 rpms. Originally I was hoping to improve gas mileage. I could go with a lower ratio but that affects 1st gear, which is low already. I could change the overdrive gear. Most of the people I've talked to on this board have recommended going with a 250. I may do that some day. For now I've decided to drive it the way it is.