I want to uprgrade my stock 17' wheels. What is the largest tire I can put on there without rubbing. I tried some 18" Concept Neeper Haaz on 235/40ZR18 but I think the rim itself is too big. I got them from a guy who had a Q45. I am going to purchase "something" tomorrow and I want to make sure I don't get a rim that is too wide. I don't think all these wheel guys know what they are talking about.

 

it really depends on how wide the rim is... I dont think you can go more than a 9 inch winde rim on the rear and 8 on the front.. so a 255/35 would be the biggest and even at that pushin it for the rear end... 235/40 up front or 235/35

 

actually the 255 might fit in the rear. up front though widest would be around 225-235 (235 might not fit!).

 

www.volkracing.co.jp

click on several wheels you like, and there will 18"s fittment chart for the altezza. to be safe, 18*7.5 215/40/18, 8.5R 225/40/18

 

Thanks for the help folks!! I was glad to have people to talk to about this. Sometimes the rim shops will tell you anything. I ended up keeping the Concept Neeper Haaz 18x8.5. I had to change tire sizes on the back, that's where it rubbed. I put on some 215/35/18's all the way around. It doesn't rub, at least not so far but it sure fills the wheel well out nicely. I will have some pics coming soon!!

 

Here's what the finished product looks like. Thanks for all the wheel info folks

 

I am suprised a 215/35 fit on a 8.5 rim....

 

Yeah but the wheels look ALOT WIDER than the tires. Maybe get some fenders and it'll look better. (Try WALD.)

 

That is what I meant an 8.5 is damn wide and in the pic it looks like the tire is not happy being on that rim so to speak..

 

I agree. The tire is obviously stretched on that width of rim. The rim doesn't appear to have much protection from road irregularities or curbs.

The rims and tires just don't look right.

 

Ouch! Also, if the tire is sticking out of the wheelwell then the gravel, dirt, tar, (etc) spray will be much worse. Hate to think of a big ol rock being kicked out that far... yikes!

Percy

 

Yeah, the 215 is way to small for that width of a rim. If you're having rubbing issues, I'd look at the offset. If these came off a Q45, I can't image that the offset would be correct for a IS300 (but then again, it's probably a +40 which is just a "generic" standard offset which would work on a IS if the rim was 8" wide)

Also, a 8.5" in the front is obviously too large. A 8" or 7.5" would be the correct fit (8.5" in the rear with the correct offset would work perfectly) Hell, with the correct width and offset, you could have squeezed a 19" in there!

 

Though the IS3 that I know (Dads) is running 225 35 18's on 7.5 inch rims. Nothing sticking out of the wheelwell. +45 offset.

Percy

 

Thanks for all the info folks. I am looking for a set of 7.5 inch rims. For Now I will be putting the factory rims back on. I will be selling the concepts. I don't want to screw up anything. I'll be trying to do this in the next month or so. You guys really have some great info.

 

sorry to disappoint u K but we are just giving you info that might help you out alittle bit...I know you must be bummed that the wheels dont fit right...