Why does my steering wheel vibrate over 60mph?
I don’t know what sort of mechanic you went to, but it’s all to do with wheel balancing. Take it in to a reputable tyre depot and ask them to balance the wheels, they take each one off in turn, spin it on a machine and add lead weights to give perfect balance. It’s usually the front wheels that’s the problem, but all four shouldn’t take more than twenty minutes and should cost no more than a few pounds per wheel. It’s not dangerous, but it’s annoying and will kead to increased tyre wear.
