Originally Posted by SeaSuckerTesla

There are a couple of errors or assumptions in your response... First the bike is not suppose to bounce if properly secured... Second the roof is not made of aluminum.
Also the whole roof is glass so all tires rest on the glass, the important part here is that the rear tire rests close to the cross bar in the middle of the roof. and the front tire rest close to the windshield. Finally the pedal crank needs to be secured with included velcro straps if not they can start spinning and hit the glass causing it to crack