Originally Posted by DXL XLR8
What is the largest rims/tire size I can comfortably put in a F30 and not have any rubbing issues, etc.?
This may or may not help. I just did some sizing research for my track rims. Though only 18", the information or pics may help to understand clearances.
Here's a chart I did to compare stock sizes with aftermarket 18" rims. I was going for lightweight which is why you see a limited rim selection. For reference, I have the 19" 403M's.
The stock 225/40/19's fronts are 26.1" diameter and the rear 255/35/19's are 26". I only took pics of the front since that is most likely where the issue would be. It looks like you can't go much bigger than a 26.5" diameter tire in front. The tire width will be dependent on your wheel offset but based on the stock 19's, you have about 20mm of clearance from the tire to the strut. Since I was running a square setup, I knew whatever I picked for the front would work in the rear.
Here are pics of the clearance on top
Here are clearances from the strut.