rear offset 18x10
 

I know this is kind of an old subject but I just recieved my new wheels from forgestar, and I am disappointed to see that they don't have as much offset as I was hoping for. I am trying to get them to fix it because I want to run 275/35 tires and a lot of negative camber, which pushes the wheel outward. I am afraid I am going to cut the tires. I measured the offset to be just under 40mm, if my math is right. I used a straight edge to measure backset at 7.12 inches, and the wheel lip to be .50 inches, so 7.12-.50-5.00(distance from inside of lip to 0 offset)=1.62=39.xxmm. correct? There is no marking on the wheel that seems to correspond to offset. please let me know if I need to send theese wheeels back. I have to be able to run these tires to be competitive in my autocross class, and I don't want them to be rubbing, or sticking out even. seeing as porsche has a bulletin that states the rear camber should be adjusted less negative(within specification) to achieve proper tire clearance when the stock offset is 47mm and stock tires are 265/35/18 I am thinking I am going to definitely have clearance problems. anyone out ther had a rear wheel/tirre combination that would have similiar offset? do you have any issues with tires rubbing?

More neg cam pulls top of tire inward, which will reduce the chance of rubbing. I'm running 18"x10" with 265/35 and an offset of 43mm with no problem. Rear cam is at -2.0. Until you get camber set and wheels on I don't think you can be sure you will have a problem.

Your math is off. 1.62 inch = 41.1mm

You should have no problems with that combination. I run a 19x10 +31 offset with a 275/30/19 tire with no problems.

I'm on 19x10 with 41mm offset in back with 265/35/19 right now with no rubbing issues... (not the same wheels in my sig)...

Might be a bit different with your wheel type/design and offset... mine are currently a 3 piece reverse lip..

no, more negative camber moves the whole wheel outward. the top of the strut is fixed, the control arm adjusts outward to increase negative camber, the top does not move out as much as the bottom, thus more negative camber is achieved. that is unless you have some kind of coilover setup that is adjustable at the top. are these available? would it work with a stock spring?

I am looking for some m030 USA springs and base rear sway bar, as well as a GT3 front bar, or other adjustable front bar. so I may be interested in the sway bar you mentioned.

johnny, I guess if 19x10 with 31mm offset is fine with the 275/30/19, I should be fine. my 275/35/18s are a bit taller. do your 31mm offset 19s stick out farenough to where they would hit the fender when compressed, but it just never gets that low? what is your ride hieght?

Needless to say, I run a very aggressive set-up with my vehicle. However, before doing so, careful calculations were made with regard to clearance. Keep in mind, that my vehicle is not tracked or auto crossed. Nevertheless, its often driven aggressively on the road, and I have not had any issues with regard to rubbing . Although, I must admit the set-up is about as aggressive as one can go. I'll shamelessly post a photo so you can see the ride height. :)

Damn, that's a sharp-looking car!