DIY Electric Bike Conversion

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Thu May 21, 2015 12:52 am

So I've got some free time this summer, and I wanted to make an upgrade to my worn out mountain bike:

So basically, I usually only use it between classes or on smooth pavement around town (ranges less than 5 miles generally) so I wanted to try my hand at a cheap and effective modification to convert it to be motor powered

The concept I'm hoping to try is to simply mount an electric drill with a right angle attachment to the frame and use it to drive the back wheel with a "friction drive" system, controlling the speed with a modified handbreak, and maintaining the ability to ride the bike manually without resistance

Right now, I'm planning to use the drill's original battery, a right angle attachment from the hardware store, and a second rubber wheel rubbing against the main tire to achieve this.

This is the first "automotive" project I've ever tried, so I wanted some input before I purchase the drill and start putting holes in my bike from. So are there any motor-heads out there who can confirm that this idea may work or steer me in another, more effective direction? Keeping in mind that this would be used for short trips, must not be too loud (which takes a gas powered motor out of the question), and requires very little modification to the bike.

First post in a while, but thanks in advance for any input y'all might have
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Thu May 21, 2015 1:31 am

I think the lateral forces that will be experienced by the drill and bracket will be larger than you expect, given the dynamics of slight bumps in the road and drills aren't designed for that kind of loading.

It would pay to run through some calcs with the drills output power, speeds and torques and gearing ratios, this will help give some understanding of feasibility also.

I saw this recently, I guess its many times more complicated than a friction wheel: But a simpler version would have a battery and inverter and non of the smartphone integration. This could also be used to recharge the battery when you brake (brake lever would be a switch that connects the charging circuit across the motors input/output)


The motor in it looks very similar to a some washing machine motors.
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