I am on my third set of Run Flat Tyres on a 2008 3 series touring. Michelin Primacy 205/55 R16 tyres have been fitted each time. Last time the front tyres were wearing down, I had a major repetivie road noise problem that sounded like bearing noise, but was traced to uneven wear on the tyres. Basically the tyres were lumpy at one point on the perimeter. Thinking that this was a faulty set of tyres, they were replaced with the same type. Having now done a further 20,000 miles the noise is reoccurring, with between 4 and 5mm of rubber remaining. Is this a common problem with Michelin's or is it a combination of Michelin primacy on BMW 3 series. I have been advised to fit Continental run flats next time, but are they a good alternative or should I consider an alternative manufacturer? Would it be appropriate to fit different manufacturers tyres on the front and back, or should I always keep to the same type for all 4 tyres?