[dradernh]

Originally Posted by Will43

This car will be a street and fun road driver for me.

Hope someone has tried this or can give me guidance.

Front

Note: fitting wide front tires on this car is a principal downside of ownership

I have Apex 18X9 ET42 ARC-8 wheels in the front with 255/35-18 PS4S tires on them. The fenders are rolled slightly and the camber is -2.6°. I have hub extenders and 8mm spacers installed, too. The fit is entirely satisfactory on my lowered car. (Pics here (note the 17X9 ET42 in front), although with different 255 tires: https://www.2addicts.com/forums/show...2&postcount=18).

The negative camber was achieved via camber plates that came with a coilover kit I bought for the car. Because there's not much room in front (made worse when lowering it 1¼", as I did), I recommend contacting Harold at HP Autosport (HP Autosport) if you plan on installing coilovers. Harold has a list of coilovers that offer more room in front than do other coilovers.

Rear

I have Apex's 18X9½ ET58 ARC-8s with 5mm spacers back there and the same 255/35-18 PS4S tires. Those fenders are also rolled slightly, the camber is -2.3°, the rear is lowered 1", and the fit isn't an issue.

I'm afraid I'm not conversant enough with this stuff to say how well and under what circumstances 18X9 ET42s with the 255 PS4S would fit in back. My guess is that it will work. It might be worth a call to Apex, or to Harold, as this is their world. Other members may have useful and specific input, too, of course. My solution was to take my car to a shop that does only this sort of thing and only for BMWs.

Note that the BMW-specific Michelin Pilot Super Sport tires in 245/35-18 that came on the car when delivered have a tread width of 9.2" and a section width of 9.7", and the non-BMW specific PS4S tires in 255/35-18 have a tread width of 8.8" and a section width of 10.2". If I'd known this before I bought the PS4S 255s, I would have chosen the 245 PSS tires for the greater amount of tread where the rubber meets the road.