widest tire size for z4m with stock suspension?

[Fen335i]

Is there a consensus on the widest tires you can go with (front and rear) on stock suspension with stock wheels without rubbing? I need to replace my OEM Contis and am looking at options...

[Daemonblitz]

285/35-18 rear and 245/40-18 front is doable. Haven't heard of anyone going wider with stock suspension on the stock wheels.

[Fen335i]

No rubbing with that setup? Seems pretty wide.

[Kgolf31]

All depends on what tire. Some have more square side-walls that don't allow that spec.

Are you doing this for looks or actual performance

[cgroppi]

Originally Posted by Daemonblitz

285/35-18 rear and 245/40-18 front is doable. Haven't heard of anyone going wider with stock suspension on the stock wheels.

For autocross, I run 285-30 Hoosier A6s front and rear on stock wheels with stock suspension. I need a 5mm spacer in the rear.

You'll hit the fender wells with the tire at full lock before you hit the strut in the front. The short Hooisers fit because they're 1" smaller diameter than the stock tires.

Also, a 285 street tire will never fit on an 8" wheel, nor would you want to try. This craziness is an autocross specific thing for special tires, with rules that require stock sized wheels.

I bet you could fit a 255-35 in the front, though. You'd just have to try it. I'm not sure how well it would work. You'll definitely get more grip in the front, but they may end up being too floppy on the sidewalls on an 8" wheel.

If I was autocrossing in a street tire class, I would try 255-35s square, or 255-35s in the front and 265-35s in the back. The closer to square you get the tire sizes, the less understeer you'll have.

Tirerack will allow you to return tires that have been mounted but not driven on. If you want to fit check, order one tire and try it out. If it doesn't fit, return it.

[Fen335i]

Thanks all. This is primarily just for the street....only Autocross 1 or 2 times a year with the car, so its more about looks than all out performance. Maybe I should go with a 245/40 front with 275/35 rear? I know tires vary....I'm looking at the Mich Pilot super sports.

[The HACK]

Whatever you do, make sure to check the minimum width required for the particular tire as recommended by the manufacturer. Some 255 wide tires may require 8.5" or wider rims to make sure the sidewalk can still sustain the load.

I wouldn't put anything narrower than the tire manufacturer's specified rim width on the car if it's to be driven on the street.

[Fen335i]

Guys - I found a set of Michelin PS2s that are 245/40/18 and 265/40/18. According to Michelins web site the stock z4m wheels will work with those size tires. Anyone think they will rub???

[XMetal]

If you're doing 245/40/18 front and 265/40/18 rear, which will cause you to have different rolling diameters between front and rear. Would that be an issue with the traction control, ABS, TPMS, etc...?

[MGRMLN]

I'm thinking of mounting up Michelin Pilot Sport 245/40-18 front and 275/35-18 rear. Would this work on stock Z4 M Coupe rims? I'm running the Eibach pro-kit springs and 10 mm spacers all around.

Thanks!

[BIMMERGUY91]

thats what im running. it works fine and im on coilovers

[beta]

Same, coilovers running PSS 245/275, highly recommended.

[dubsesd]

Tires wider than 245/265 will look like floating devices on your stock wheels.