Mick F wrote:Agree.andrew_s wrote:Mick F wrote:The speed of rotation is much higher.
Because the road speed is the same, that makes no difference to the rate at which the brakes put heat in to the rim.
I'm saying it's going faster past the blocks.
It's not going faster past the blocks.
The rim moves past the brake block at the your riding speed, the tyre aside.
The axle is stationary with respect to the brake blocks. The axle is moving at your riding speed relative to the road. The bottom of the wheel isn't moving relative to the road. Therefore the bottom of the wheel is moving at your riding speed relative to the brake blocks, and, since the wheel remains the same shape, the top of the wheel is also moving at your riding speed relative to the brake blocks.
Wheel size and RPM has no bearing on this at all.
In fact, it's likely that the rim is going marginally slower past the blocks than with a larger wheel, since the tyre takes up proportionally more of the total wheel diameter.