Originally Posted by jbass524
I've done extensive modification and tracking with an E92 so I have some experience. I hope it's good.
APEX makes an 18X8.5" wheel for the E9X. If you want track wheels go square and as wide as possible. Camber is probably the single best handling upgrade you could do and besides wheels, would be my first.
Not sure if this is the case, but tire wear on the inside has a lot to do with the toe than and with adjustable camber plates you can easily (5 minutes) adjust them for street use after a track day.
BTW, 17s out perform 18s in some cases and at the level of driver here, me included, 17s would never be why you're not as fast as you think you should be. Add that wheel and tire cost is a lot less and I would always opt for them unless I was sure 18s we're better.
Replying to an old post here, but +1 on the camber/toe comments & wheel size.
There is no reason to fear that "lots" of camber is going to wear your tires more quickly. Depending on the car/driver you can get MORE life out of your tires with a generous amount of camber than you get with none.
Lots of toe, on the other hand, eats tire tread for breakfast and craps out treadless tire carcass around lunch time.
My experience isn't based on an e9X, so someone correct me if I am wrong here, but for a mostly streat setup I'll bet you are going to want ~2 degrees of camber in front and ~1.5 in the back, with toe set at factory spec. As has been demonstrated the camber in the front will also allow a 17x9.5" wheel, along with 255 rubber. I'll hazard a guess that the wider 255 rubber with the required camber will last longer than the narrower rubber with no camber.
As far as wheel diameter goes I prefer the look of a tire to the look of a rubber band, (I know that is just me
) and as stated above 99.9% of us who are trolling the internet for advice won't see a performance increase from a shorter sidewall, and that becomes even more true when you add a good performance tire with a stiff sidewall into the equation.