# Leonardo's gear sketch

1. Jan 6, 2008

### h.g.Whiz

Suppose that it was possible to construct gears smaller than ones of modern ten speed bicycles(nano gears) and suppose your chain or belt could turn them and withstand the friction. First gear of course would be the same as a modern ten speed in order to get it moving. If the last gear's radius was 10,000 times smaller than the first gear how fast could this megaten speed bicycle travel

2. Jan 6, 2008

### Cyrus

How big are the wheels, how much force can the person push down on the pedals?

You can find it if you know the angular acceleration at the pedals.

Last edited: Jan 7, 2008
3. Jan 7, 2008

### Danger

It's certainly already possible to make gears way smaller than those in a bicycle; try dissecting a Swiss watch sometime. (And they have made nano-gears, but there's no immediate commercial use for them.)
The only theoretical limits that I can think of when it comes to a gear train show up when either the friction heat or the inertia overcome the structural integrity of the gears and cause them to fail.
As for the practical limits, Cyrus has it covered.