On 25/06/2018 18:45, The Natural Philosopher wrote:

No, the 'rolling radius' is th *circumference* divided by 2 x PI and HAS
NO relationship with how far the axle is from the road.

It doesnt change as you go over a slpeeing policeman.Â* :-)



Oh, it does. It even changes when you go over the painted lines.
Maybe you are thinking of cart wheels with steel tyres and not knobbly
bits of rubber stuck to a flexible belt?