i have just bought a focus zetec collection,1.8i lovely car but the noise levels inside are loud ie road noise ,sounds like wheel bearing somewhere,have had it checked by ford and they said all bearings are fine,the thing is the tyres on it are 2 fronts toyo proxes cf1 and the rears are bf goodrich one side ,the other side viking protech 500,the two fronts are new so was thinking of getting two for the rear to match the front,tyres are 195/60/15 could this be causing the noise? many thanks.