Wednesday, 13 January 2016

Chain Driven Front Wheel Drive Ebike

Chain Driven Front Wheel Drive Ebike - Why?

If you are trying to do an ebike on the cheap then you might be a bit resistant to the thought of spending £200 on a Chinese no name hub motor, with lots of plasticy control and unessassary electronics.

This is why I purchased a chain drive motor, it was about a third of the price of a cheap hub motor. In fact I got everything I needed to electrify my bike for £180 including batteries (Panasonic Batteries!).

Be Prepared for Ugly

The result is a dog ugly bicycle that I know I can get parts for if they go wrong becuase I bought all of them individually.

Chain Driven Front Wheel Drive Ebike - How

You will need the motor. Unite Motor Company make lots of different electric motors. You will need one that is geared down for torque.

You will need to mount the motor above the tire quite high up, where it will not stick out too much. Or you can mount is sticking out of the side lower down, which make the bike less wobbly (lower centre of gravity).

BMX Rear hubs are 110mm OLD, i.e. the drop out are 110mm spacing. Front forks are 100mm spacing so you do not need to widen them much to fit in a BMX rear hub.

In my case I sawed off the drop out on the left hand side (right hand side in pictures) and welded back on. This was an easy job as you can use the axle to hold everything in place. Just be sure to warp some tape around the axle to stop the weld blobs sticking to it.

Note Re-positioned LH Drop Out (Right Hand in Picture)
Being you have just misaligned the drop out the wheel will not sit centrally in the forks so you will have to dish the wheel a little more so that the rim comes back to centre. You will need a spoke key to do this.

Plate Welded on to forks
The plate will need to be quite thick, even a small motor will flex a thin plate, a diagonal support to the rear will help keep things ridgid. Mark the holes for the bolt carefully, and lengthen the hole with a file so you can slide the motor away from the motor to tension the chain. Nyloc nuts are advisable.

This is so much simpler than trying to fit a chain driven motor to your rear wheel, whilst keeping the pedals. If you are running a low voltage (24v) system like this one here you will need fat wires to avoid reistsance as the wires will have to run from the back of the bike to the front, which in this case is about 1.5 meters.

To look at the whole bike, please visit my DIY Long Tail E Bike Page

Close-up of left hand drop out.

Environmental Consultants Bristol

Illustrator Devon 

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