Can you also ride non-runflat wheels with the F01? Can you possibly even put normal tyres on the Runflat rims? I am currently looking for new wheels, but on eBay I only found runningflat wheels. I would have liked to have original BMW rims. 21 inch Runflat wheels are definitely completely intolerable, hard like a board. They must be gone. 18 inch are the standard tires at 750i. 21 inch as far as I know this is the largest permissible size. 18 inches are pretty balloon-like with a flank height of 50. 19 inches would then have a flank height of 45 and 20 inches 40. I’m a little unsure about driving comfort. What are you driving?