Interesting point Martin; Does anybody else know?? You describe a 'thrumming' noise which is very accurate, it does indeed sound as if a wheel bearing is on its way out although on my car the noise starts from as low as 20mph and then remains at the same level regardless of speed, which is not consistent with a wheel bearing. Anyway it can't be my wheel bearing, since I've just had it changed, even though when removed the original was absolutely fine. Oh well!! Cheers, Derek