Cannot change from run flats?
I have a 645Ci and National Tyres (UK) told me today that once your suspension etc is set up for run flats you cannot change to normal tyres otherwise your insurance would be invalid.
Is that right? they have also sold me two Continental run flats for the rear when I have Bridgestone on the front. Should I keep to the same manufacturer or does it not matter?
All advice gratefully received.