[Novel]

Hi,

I'm thinking about R17 square setup for the next season. I think I'll go with 9" wide rims with offset around 30. However, I'm not sure about tyre size.

Apex's fitment guide suggests 235/40/17 for square setups and that's the widest what they recommend either for square or in front.

However, for Z4M it suggests various sizes, up to 275/40/17 on 9.5" ET35 rims. So I'm wondering if I'm missing something, and what's the difference between Z4 and Z4M that allows Z4M to have larger and wider rims fitted?

From what I can see, part numbers for the front fenders are the same between 3.0si and Z4M. Fender liners are different, but I guess that's only because of the cooling ducts in the Z4M bumper. IIUC, front arms also have the same geometry and the only difference is Z4M arms have a stronger ball joints and different castor due to different rear bushings...

On the other hand, I'm running 235/40/18 on 8.5" with ET35 (those are basically 4 rear OEM ET50 wheels with 15mm spacers all around) and I don't really understand how 275 could fit... I'm also somewhat lowered with ST X suspension and have around -2.7 front camber. Even with that setup I have a slight rubbing in the inner fender liner, around the place where the bumper connects the fender, closer to the outer edge.

So I'm curious to know what's the experience on running setups like 245/255 on the front? Does it maybe need some stiffer suspension to fix potential rubbing issues?