Motors / Engines: January 2010 Archives

I'm working on a bicycle assist motor project. I thought about using a hub motor or chain drive but given the economy, I'm going with a friction drive. Friction drive is cheap, has few little moving parts to go wrong, and is cheap. I think I can make it using parts almost entirely found around the shop -- with the exception of the friction roller.

Now what I like about friction drive is if you use a roller with a one-way bearing and take advantage of some physics, the motor can release from the wheel entirely when freewheeling, so the bicycle remains entirely pedal-able on its own.

I decided to go with rollers from the defunct EV Warrior project. They're available on the surplus market, have one way bearings, and are nicely knurled. Other people are making their own friction rollers from BMX wheel hub extensions, but they don't have one-way bearings.

Here are some dimensions almost entirely for my own benefit.

Shaft OD0.500"12.70mm
Shaft ID0.315"
(a tad over 5/16")
Shaft Width3.016"76.61
Roller Width2.375"
2 3/8"
Roller OD1.275"
~1 1/4"
Key Notch Width0.130"3.32
Key Notch Depth0.411"10.4

About this Archive

This page is a archive of entries in the Motors / Engines category from January 2010.

Motors / Engines: December 2009 is the previous archive.

Motors / Engines: February 2010 is the next archive.

Find recent content on the main index or look in the archives to find all content.