Wheel Fitment - Offset Explaination
 

Hello All.
No matter how long I've owned the car, I still consider myself a newbie as compared to most of you. I've been looking at wheels (I have a 1985 'S' with 4x110 pattern). If I'm looking at both 15x7 and 15x8 wheels - not really knowing which might be better (same size at all four corners, I suppose). What is the difference between +20 offset, +25 offset, and 10 offset (I assume that means "+"10 offset, but not sure). Any insight would be appreciated.

Basically, I'm looking at several Rota brand wheels.

thanks!

lower offset will give you a wider stance. I ran 15x7 +0 offset with rolled fenders, it was a really nice fitment. I have a two 15x7 +0 4x110 wheels if you are local to Clemmons and want to try them. I also ran 15x8.25 +0 and that was super agressive. Check out willtheyfit.com as well, it can help you figure out where you are at

I got the Konig Rewinds which were 15x7 +20 wheels. They rub a bit on the front with 205/50x15 Dunlops Star II on them. I didn't notice this until I was driving very aggressively on the twisties. So I did an emergency fender roll on site which cured the issue. Not happy I had to do that but I plan on a respray in the future so I can live with it for now.,I suspect a +0 offset would require a rolled fender for any spirited driving. Also depends on the tire width as well as mfgr too. Things vary but at 15x7 all the tolerances are very close so it just depends on your car the wheels and tires you select.

I had some enkei compe in 15x7 +25 with 205/50/15 tires and they fit good and i didnt have any rubbing issues.

When looking at the car from the front or rear, the center of the wheel is 0 offset. If the hub (where you bolt the wheels up) is further toward the outside of the wheel/car you have a positive offset. If the hub is located inside, toward the brakes, that's negative offset. You won't see that with an RX-7 though.

So, more positive offset will sink the wheels in toward the brakes, less offset will poke 'em out. For example, aeenox's wheel's hub is 25mm toward the outside of the wheel from the exact center so he has a +25 offset.