I have a 2012 C70 cabriolet that has a vibration similar to an out of balance wheel at between 60 mph and 75 mph that is not transmitted through the steering wheel, over the last 6 months it has had new Tyre's fitted on the front and rear, my garage has checked and rechecked the balance of the wheels no problem, during a full service a badly worn half shaft joint was found and both are now replace but the vibration is still there. During an MOT the engineer has checked everything underneath and no problems are visible.
does anybody have any suggestions.
mike