I have a question on how you know how tall the tire and wheel will be after you change them. I want to go to a larger wheel and I want to figure out how much tire to put around them without screwing up the speedo to much. Like right now I have 235/75 15 tires(factory is 70 so the speedo is slightly off now) on and if I were to go to 18 or 20 inch wheel. What is the best way to decide to what tire to wrap around them?

Hopefully I explained it good enough, if not ask and Ill try to go into it deeper.

 

Search on google for a tire diameter calculator and enter in the rim and tire size of your stock tire to find out the factory overall tire diameter, then figure out what size of tire will give you the same overall tire diameter using an 18 inch rim and lower profile tire.

-Lenny

 

this link was in another thread, you can use it to compare tire sizes to give you a good idea....

Clicky!