Looking at The Whisperer discussing an unfortunate wheel loss incident [routeone/Whisperer/20 June], by my numbers, getting a 100kg wheel to 150kph probably needs quite a lot of energy adding from somewhere, depending on the initial speed of the bus.
The diameter will increase slightly when unloaded and the wheel studs could give a slight 'flick' as the doomed wheel departs the vehicle if under load at that moment, but it seems unlikely that the vehicle speed plus any extra momentum would mean the wheel would move faster than even our world speed record for a service bus.
The rotating wheel carries a lot of energy, even at a low speed, which is why they're so destructive (and why fuel savings from alloy wheels, lightweight tyres etc. are justifiable).
Of course, the aim of the game is to keep the tension in the wheel studs in the first place.
John Bickerton, Reading Buses
