I'm curious how wide I can go on the staggered OE wheels without spacers and no rubbing on my LCI e90 335i xDrive M Sport. Anybody know? The wheels are 8x18 front and 8.5x18 rear, offset 34/37: style 193. I'm giving thought to going 245 front / 265 rear... Good idea? Bad idea? Backstory: I have a square set of 8x18 aftermarkets that I normally run all year round, but I'm considering making those dedicated track and snow wheels, and so I'm thinking of running summers on the OE wheels this year. Last year I ran 245s on the square set for the summer, so I know I can at least go that far in the front without rubbing issues. But I've never gone more than 255 in the rear. I'm curious if a 265 or even 275 would start causing issues? Oh, and unless someone talks me out of it, I'm planning to buy Michelin Pilot Super Sports and hope like hell they last longer than the last two sets did. (Hankook Ventus R-S3 and OE Bridgestone Potenza RE050A) Many thanks for any help y'all can offer! (My apologies if this question has been posed and answered... alas my forum searching capabilities are somewhat lacking.)
I have 255/40-17's on Apex Arc-8's, which I think have a 40mm offset, no rubbing that I've noticed. Ymmv, as actual tire width may varies across brands. Assess the treadwear rating to judge tire life - supersoft tires with low tread-wear ratings mean short tire life.
Thanks MGarrison. I did some more research and that tire isn't rated for anything more than a 255 on an 8.5x18 rim... if I want to go wider I'll need to get new wheels. I'm going with the Michelin's this time because the PSS have a treadwear rating of 300 and because of Michelin's treadlife warranty, even though it's cut in half to 15k miles for staggered sets... still more than I got out of the Bridgestone's that came on the car.
One advantage of a square setup is you can even out tread wear by being able to swap fronts to the rear - it also helps reduce some of the understeer inherent when the fronts are narrower width than the rears. Check bimmerforums.com, e90post.com, and bimmerfest.com also for what others have fit. Tires are always a series of trade-offs & compromises; ultimate grip & immediate steering response means low-profile tires with little sidewall & a soft tread compound. For those gains, you sacrifice tread life plus the tire's ability to soak up bigger bumps, and lose some ride quality with a higher risk of wheel/tire damage from bumps/potholes. Conversely, harder rubber means you'll have less maximum grip in all directions, so stopping distances may be comparatively longer, you have less cornering grip, and ride quality may be somewhat better if you go for a tire with taller sidewalls (ie, higher aspect ratio), which also means steering response may not be quite as sharp/immediate. But, a longer-lived tire means less-frequently having to shell out for tires. Harder rubber also means it's less advisable to scream through turns like a banshee, and with some increase in stopping distance, tailgating becomes even more of a bad idea than it was before! Considering that it's exceedingly hazardous to everyone else on the road, not to mention one's self or license, to drive everywhere like the world is a racetrack, I'm not sure there's that much logic to running the stickiest of rubber for street driving. In the new-car comparison wars, such high performance rubber that BMW throws on its cars gives it bragging rights about handling, grip, & responsiveness; however, fun has it's price, which pops up most rudely & substantially come replacement time.
