[Elliot]

Within the space of a year, I plan to purchase a used F33 (RWD 430d, probably).

I've started to feverishly formulate a potentially crazy and unworkable (I hope not) staggered set-up to replace the OEM set-up.

Here's what I'm thinking:
Front:
8.5J or 9J x 19" deep-dish
245/35R19
Rear:
9.5J or 10J x 20" even-deeper-dish
275/30R20

Using the OEM 19" set-up for comparison, my fronts would be -1.1% in diameter, and the rears would be +1.9% in diameter. I would be willing to do some fender rolling (and/or slight camber adjustment) in the back to squeeze in them 275s, and if I were to lower the car, I'd go with HAS so I could dial in a no-rub-but-still-pimpin' amount of drop. I'd prefer roughly equal tire-to-fender gaps front to rear, so rake would be pronounced, though not excessive, I hope.

Concerns:
1) The fronts would be 2.6% smaller in diameter than the rears (26.5" vs. 25.8"). Would this somehow have catastrophic performance or mechanical consequences? I have no plans to track this car or even drive aggressively (except in a straight line), for what it's worth.
2) Am I being overly optimistic that some modest fender rolling/camber adjustment would be sufficient to make the 275s fit?
3) I'm assuming that the staggered 19 & 20 look will be gorgeous, as rear wheels often look disproportionately small to my eye -- likely due to the comparative bulkiness of the rear quarter panel region versus the front fender region. Nonetheless, if you have photographic evidence demonstrating the contrary, please share.

Thanks in advance for your insight.

[Spielzeugauto]

The 275 tires and the wheel sizes won't be a problem, they fit.

But that's a large diameter difference between the front and rear, the abs and traction control are likely going to freak out. A 235/40-19 would solve that.

[Elliot]

Originally Posted by Spielzeugauto

But that's a large diameter difference between the front and rear, the abs and traction control are likely going to freak out. A 235/40-19 would solve that.

Oh, okay -- really good to know! I definitely wouldn't want those systems to freak out!
I had actually strongly considered the 235/40R19 as well, but for some reason had this overwhelming concern that the fronts' sidewalls would look too tall n' meaty (relative to wheel diameter) when compared to the rears', which, in hindsight, seems unjustified... ...perhaps especially if I opt for 9"-wide wheels up front, as the 235s will be more stretched (slightly diminishing the appearance of sidewall 'tallness') than the 275s on the 10"-wide rears.

Thanks for chiming in!