After reading that minis handle better with 10" wheels than with 12", I decided to measure the circumference of the stock standard set-ups.

My Morris has 145 SR 10 tyres. These measure 153cm circumference with fairly complete tread. (so 653.6 revolutions per km and a radius of 24.3 cm)

The Rover tyres are 145 / 70 / 12 and these have a circumference of 159 cm. (so 628.9 revs per km and a radius of 25.3 cm)

So the car is only raised by 1 cm by changing the wheels. They feel about the same weight, but I didn't measure them and they've got the same tread width. They would have a bit more rotating inertia but not much.

Therefore it must be the sidewall height and associated flex that makes the difference in handling??

Anyone know (maybe from a catalogue) what the circumference of typical 165/60 or 175/50 aspect tyres have? Maybe these are taller again?

M