Install eBike torque arm assembly for rear hub motor

November 21, 2010 · 0 comments

After deciding what angles to mount the arm and mounting bracket (as shown in the previous video) the next step is to figure out how to mount them.

The mounting bracket needs space between the dropout to allow for the mounting nut and arm. I could have put several spacers between and then used the flanged axle nut to secure it all but instead chose to use the axle nut as the spacer. I think this will make for a stronger attachment of the hub motor to the dropout.

Using the axle nut as the spacer required using an extra nut to attach the mounting bracket. I found a 14mm 1.5 pitch nut and washer at the hardware store to use. Unfortunately, I couldn’t find a flange nut. This means that I’ll need to use two different size wrenches to take the wheel off. I’ll keep hunting for a flange nut. It will be easy to change this later. If I use a flange nut, I’ll only need to carry one large wrench instead of two for road repairs.

The large space between the dropout and mounting bracket causes a steep angle on the arm to the mounting point on the stay. I fixed this by bending an S curve in the arm which brought the top of the arm closer to the stay.

There are two mounting hole options at the top of the arm. The long slot is for the tube clamp provided in the E-BikeKit torque arm assembly. The round hole can be used for some other method of attachment.

While at the hardware store I found an insulated clamp that looked like it would be easier to install and remove than the tube clamp. I’m thinking it will be as strong as the tube clamp as long as I’m careful how it is mounted. I may switch to using the tube clamp if it looks like the other clamp isn’t as strong or loosens up easily. It will be easy to change later as needed.

Lock nuts were used to secure the bolts. These are only designed to be used once. If I have to take the wheel off and disassemble any part of the assembly, I’ll have to use new lock nuts. I put a drop of thread lock on the threads as a further precaution against loosening.

After riding the bike for awhile, I’ll check that everything is still tight and secure. I may change to the tube clamp at that time.

The next step for Leah’s electric bike is to mount the rear rack and battery.

Click here to see all posts about Leah’s Electric Bike Conversion.

Stay tuned for more details as this project proceeds.

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