http://forums.mtbr.com/showthread.php?t=283367
It is a hub.
A bike hub is mainly turned on a lathe. Spoke holes are drilled and if it's a hub brake or a rear hub there may be some milling too.
In the bearings that go between the stationary part - the axle, and the rotating part - the hub.
on the rear wheel, at the hub. it's the bit that the chain runs over.
polyp
bicycle hubthis is far from a complete answer, I've just started learning how to restore vintage bikes. But I know the hub is the circular metal peice that allows the tires to spin. It is in the middle of each tire where the spokes meet. I know this cuz I have a early 1930's Montgomery ward cruiser that needs a new back hub. hope that helps.The Bicycle Hub the is the central part of a bicycle wheel it is circular and is connected to the spokes, at the bike hubs centre are bearings and this is where the spindle is fitted to allow rollling.
Usually by having a special rear hub which measures the output of the rider.
polyp
No. there are quite a few other places where you can add an electric motor to a bicycle. However, the hub motor is quite probably the one which requires the least amount of changes to the rest of the bike.
If you leave your bicycle in the rain it becomes a wet bicycle, or possibly a wet, rusty bicycle. I hope that was the answer you were looking for.
The rear wheel has a different hub; the gears attach to it. Alternatively the rear hub has gears or a brake or a dynamo built into it. The front hub will sometimes have a dynamo built into it, other than that it is just a plain hub.
Too much to answer here, I'll post a link.