E-Bike Drive System Question - RC-Monster Forums

BrianG · **E-Bike Drive System Question -** 10.22.2010, 11:38 AM

I was just thinking, is there any reason why a smaller drive system isn't used on the rim where the brake calipers sit? I would think it would be a whole lot easier than using an elaborate sprocket system or the use of special hub motors.

For example: The diameter of a 26" bike wheel at the rim is probably closer to 24". If a 2" rubber wheel drives the rim and is directly coupled to a motor spinning at 20k rpm, this would equate to a speed of around 40mph.

Just thinking out loud here...

brushlessboy16 · 10.22.2010, 12:09 PM

Post on Endless sphere, there are a few threads on this topic there...

:)

sikeston34m · 10.22.2010, 12:14 PM

Quote:

Originally Posted by BrianG

I was just thinking, is there any reason why a smaller drive system isn't used on the rim where the brake calipers sit? I would think it would be a whole lot easier than using an elaborate sprocket system or the use of special hub motors.

For example: The diameter of a 26" bike wheel at the rim is probably closer to 24". If a 2" rubber wheel drives the rim and is directly coupled to a motor spinning at 20k rpm, this would equate to a speed of around 40mph.

Just thinking out loud here...

I don't see why not.

I once made an experimental drive system with an outrunner motor and a small rubber wheel attached to the motor with prop adapter.

A large spring held tension against the front wheel. The front tire was changed to a smooth tread design to insure better contact.

If you drive with the rim, I only see two obstacles for this design.

Limited contact surface. You could actually do a "burn out" on the rim with the rubber wheel if over powered. This would be a great application for Castle's new torque control feature.

The other obstacle I see............

You would need to exert equal pressure on both sides of the rim. Not just the drive side.

This would help preserve balance and take it easy on the spokes of the wheel.

I've been trying to figure out how to use a Castle 1717 motor for this. LOL

_paralyzed_ · 10.22.2010, 08:48 PM

it's inefficient and you aren't considering road debris.