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[Brake_L8]

This is going to be a two-parter as far as my research is concerned... the short story is that my 128i is going to need new shocks (front right is blown). If I'm doing that, I want to lower it slightly. If I lower it, I need to make sure my wheels and tires will fit without rubbing.

The car: 2009 128i/6
The wheels: BBS CH, 17x8.5", +38 offset
The tires: Continental ExtremeContact DW in 235/45/17

So, I have the wheels/tires mounted already. 95% of the time, they're fine. Stock offset is +47, I believe, so these are pushed out to the fenders a bit more. They do not rub anything at full lock, but hitting a bump the wrong way (or with too much speed) will send the offending corner into the fender liner.

As they sit now:





I've had the car on VIR Main, and even "at speed" on track, no rubbing. My concern is that if I lower the car, I'll run into problems given the height of the sidewall and/or having zero negative camber up front.

So then, how do I make these wheels fit better? I am not opposed to selling the tires. The current 235/45 size provides almost the same rolling diameter as the stock 205/50's did. My other option (to reduce sidewall height) is to go to a 225/45 tire. That'd reduce the sidewall and keep rolling diameter about the same.

Any ideas? I really like the wheels, so ideally I'll keep them and just change up the tire situation. Or, maybe I can keep everything and add a dab of negative camber up front? I don't know what the "easy button" is for these cars like I do on the E36...

[chris82]

If you add more negative camber that will definitely help your situation. If you've already maxed out the camber in stock form, you'll need to get some camber plates.

[andrey_gta]

I just had a similar issue - front shocks. ( see my recent thread)
So I agree with you wanting to do springs too.

Your rear wheels may have more issues...Look at 17x8.5 et40 Apex Arc8 or simmilar wheels. StIG managed to fit offset 42 17x8.5 on 235 PSS
But over all people say the front is camber fix while rear is roll/ fender trim

The front is fixed with Camber like dinan plates or just teh M3/trw lower arms.

For the rear, a fender roll will help, but thats probably not what you are lookign for since you are asking.
My radical approach is In this case: how do you feel about modifying the rear wheel hub & bearing & rotor to the e9x 328i specs vs current 128i spec. You will gain 10mm clearance per side, saving rolls. Cost is about 300-350 + labour per hub&bearing, and new 328i rear rotors

[Brake_L8]

I don't mind rolling the rear fenders, I've got friends with the proper roller tool if that'll help.

I know there is a $200 set of camber plates for the front, which I could definitely add to the car. Could/should I do the alignment pin removal at the same time? Or would just the fixed camber plates work OK for the front?

[DietTab]

Dinan camber plates + alignment pin + M3 arms set me at 2.6 degrees. It will solve all your issues

[Brake_L8]

Originally Posted by DietTab

Dinan camber plates + alignment pin + M3 arms set me at 2.6 degrees. It will solve all your issues

-2.6* of camber up front strikes me as a lot for pure street driving. I'm at -2.8ish on my M3 - and while it's wonderful for track days, it's too darty on the highway (and in theory, will wear tires faster with that much camber...) for a street car.

Would -2* be enough?

[John_01]

You don't need M3 arms to solve the problem. Just camber plates with an extra 1.0 ~1.5 degrees will probably do it. You are in the best position to judge by looking at how much space you need. 1.5 degree adjustment of camber plates should give roughly 10mm additional fender clearance. The M3 arms don't provide any additional fender clearance.

[Brake_L8]

Originally Posted by John_01

You don't need M3 arms to solve the problem. Just camber plates with an extra 1.0 ~1.5 degrees will probably do it. You are in the best position to judge by looking at how much space you need. 1.5 degree adjustment of camber plates should give roughly 10mm additional fender clearance. The M3 arms don't provide any additional fender clearance.

Alright, great. I think 10mm of fender clearance up front would let me lower the car a little bit and use the existing tires. I'll measure some tonight when I get home.

[DietTab]

Camber doesn't make it darty at all, that's a product of toe settings.

[Brake_L8]

Originally Posted by DietTab

Camber doesn't make it darty at all, that's a product of toe settings.

Duh. Very true.

I think my end goal here will be to give the car about -1.5* camber up front, with a very slight drop (0.5-1"), with a smaller tire. Thinking I'll do a 225/45/17 tire, which will keep the rolling diameter (and thus, speedometer) nearly the same as stock (within 0.1%) while reducing sidewall height compared to the tires I have now.