I'm really hoping you fellow rotary lovers can help me!

Im looking to swap the 16 rims in our 1988 Rx-7 endurance car for 15 inch rims to reduce overall gearing, reduce unsprung weight, cheaper 200 treadwear tires and cheaper hoosier slicks.

Does anyone have any ideas on what offset to run for the 15 rims to fit a 225/45/15?

We are currently running a pretty decent sized spacer upfront.

Thanks

Tom

 

stock offset is 40mm so if you have spacers already you should be fine with that size of tire on a 7.5 inch wheel.
I'll take a wild guess and say that you have access to a tire machine.(with a name like "racing" and you got an endurance car)...so If it were me,I'd just try one..

 

generally we tune the car with different spacers anyways, so you'd probably need to start with something around 35, (stock is 40, but a 225 on a stock wheel will probably hit the spring), and then space it out another 13mm (1/2").

this would get you about 35-13 = 22 give or take a bit.

why only a 7.5" wheel?