I have a set of volk ce28n's with a staggered set-up 8.5 width in front and 9.5 width in the rear, on 18's. I was wondering what is the widest tire I could fit on those width rims with-out rubbing issues for one, and what would be the best street-tire for them, I already have some nitto 555 high po's on and they seem alright, but I think I could get even better grip in the twistys with a stickyer, wider street tire, oh and I don't need to worry about understeer as some might think with the staggered set-up, I think because of the extreme light weight of the volk wheels it isnt as much of an issue, cause I have oversteer.

 

I would probably go with a 245/40/18 up front & 275/35/18 in the back. I have 10mm smaller front & back, but that is because I have 19's, and was told if I had lowered my car that 245's & 275's might rub, but unless the drop is more than about 1.25" you won't have to worry about that.

 

275/35R-18 95W will fit 18x9.5 rims, so Fanman is correct on the back. But since I don't run staggered, I could not make the call on the fronts.

 

What I found
https://www.rx8club.com/series-i-wheels-tires-brakes-suspension-55/rolling-fenders-78393/

 

And this one too
https://www.rx8club.com/series-i-wheels-tires-brakes-suspension-55/largest-front-tires-wheels-possible-79544/

 

thanks for the input, would 275's fit on the front 8.5x18 without any issues you think?

 

Technically you can put 9.5" on the front with the proper offset, and put 275's on them. I have 8.5" with 34mm offset on my car right now and it pretty much maxes out the wheel well out, not up. Personally I think 245's are the best for up front, but if you want 275's I would go to a 9.5" rim. For a 8.5" rim I would say 255's maybe 265's in a pinch. Some people have put 255's on the stock rim. I personally have seen this but it seemed like the tire overwhelmed the wheel a bit.