Originally Posted by
wphamilton
Think of what the tangential speed is at the ground, in the center, and at the top. That's the speed that the spokes (and hub) are moving through the air, at those three points. Do those speeds change when the radius changes?
The spokes do not extend all the way to the ground. The wheel and tire profile must be considered, and as long as either of those are non-zero (true for any spoked bicycle wheel), the spokes of the smaller wheel will have a higher linear speed.