I am upgrading from the stock 15's on my 93 SE to 17 x 7. Every tire shop I go to for a quote gives me the size 235 45R17 as the correct size. When I used 1010tire.com calculator it told me 215 50R17 kept the closest diameter and kept speedo the most accurate. What is the difference here? If any?

Thanks.

 

The 215/50 tire is narrower, with a taller sidewall. The overall diameter is probably very close to the 235/45. Honestly, with a 7" width, I would get a 225/45 tire. You are still within the 3% tolerance (putting a 235 width tire on a 7" wide rim is not recommended by alot of manufacturers). Hope that helps.

 

go with the 235/45/17 ...

 

Personally a 7" wide rim is a little narrow, you should go with a 225, you could run 235 but that is pushing it. Since you are spending the money to get rims, go with a 7.5 or 8" wide and a nice 235, also, if you plan on going big brakes, make sure you get a lower offset and wheels that will clear.