I'm about to order a 530xiT with the 245/40-18 run flats, in order to get the 18 inch wheels which I like better than the 17 inch standard wheels. My plan is to replace the run flats with Michelin Pilot All Season 235/45-18 ($209 per tire at the Tire Rack). Is there a problem with the size difference? Any comments would be appreciated.

 

you also need to orer the spare wheel and jack/toolkit set if you take off the runflats
check the wheel rims take standard tyres - some guys on the E60 site reckon they do, I was advised they don't (but I would rust this site over a dealer any day)

 

Thanks for the advice...the dealer told me that the car comes with a spare tire (in the U.S.) even with the run flats!