Install an ebike torque arm to prevent your wheel from falling off. 

At high speeds, a hub motor could possibly spin out of the dropouts of your bike. The forward torque created by the wheel produces an opposite torque against your bike frame. By attaching an ebike torque arm to your frame and hub motor axle you may help prevent the motor from spinning out. 

This is the torque arm we used for installation of a Voilamart 1000watt Rear Hub Conversion Kit. This arm fits an electric hub axle of 10mm in width. 

Why Install an Ebike Torque Arm

A torque arm is an important safety feature for a powerful custom or DIY electric bicycle.  Most custom electric bikes over 250Watts should consider installing a bicycle torque arm. DIY ebike enthusiasts would agree that if you’re making a 1000Watt ebike or higher, you need this! An electric bicycle torque arm can relieve the stress on the dropouts of your bike frame.  Especially if your bicycle has an aluminum or carbon frame. 

Here is the 1000Watt Rear Hub Motor Ebike Conversion Kit installed in the this blog

We are installation a torque arm on this 1000Watt Ebike. To see how we made this 28 mph ebike, check out this blog. 

These torque arms can be installed on a front hub or rear hub ebike motor.  If you have a powerful electric bicycle you may want to consider installing two torque arms on your hub motor.  This link  is for multiple ebike torque arms. 

Tools Needed for Ebike Torque Arm Installation

You will need a few tools for the torque arm installation:

• An adjustable wrench to remove the bolts holding on the wheel and assemble torque arm
• A phillips head screwdriver to tighten the clamp (Make sure to pack a phillips head screwdriver on your ebike rides along with your flat tire equipment). 
• Hex Key to tighten the torque arm bolt
• Wire cutters to remove excess metal on C-Clamp

The torque arm package comes with a Slotted Motor C Arm, Torque Arm, Hose Clamp, Nut & Bolt. 

Notice the opening in the Slotted Motor C Arm for your electric hub motor.  Make sure your ebike hub motor axle will fit this slot before ordering this brand of torque arm.

 

We are Interested to hear your thoughts on these torque arms and to see your ebike conversion. Tag us in a photo of your cool ebike on Instagram. 

Here is a step by step video to help with your installation. Make sure to subscribe to our YouTube Channel.

 

If you are interested in learning about a sleek mid drive ebike conversion kit, check out this blog. 

How to install Torque Arm Ebike Hub Motor

First, make sure your hub motor is securely in place in the dropouts of your bike frame.

Next, install the washer from your Ebike conversion kit. (If applicable)

Once this washer is in place, install the Slotted Motor C Arm over the axle of your hub motor. On the bike in the example, this would only fit on one way. Make sure that the C Arm can securely snug into place against the washer.

 

After the C arm is in place, you will be able to see which direction the torque arm is fastened. The torque arm should run along the frame of the bike and will connect with the hose clamp.

To connect to C arm to the torque arm use the nut, bolt, and small washer. It might be easiest to remove the C arm from your bike to connect to the torque arm using an adjustable wrench and hex key.

This is the battery bag we used in this conversion.

Make sure that the bolt and nut do not interfere with the bike frame or gears. For this example we had to place the nut facing away from the bike since there wasn’t correct space when the bolt faced out.

 

Install the Hose Clamp

Insert the hose clamp into the narrow slot of the Torque Arm.  Wrap the Hose Clamp around the frame of your bike. For this example, the Hose Clamp fit best around the upper portion of the bike frame.

Tighten the hose clamp using the phillips head screwdriver. After the screw is securely tightened you might end up with excess metal. You can trim this metal from the Hose Clap with a pair of wire cutters. Make sure to leave an inch or more of the metal tail so that you can reconnect easily if you need to remove your bike tire. 

The battery used in this conversion is a 48V13Ah Unit Pack Power Battery.

Finishing up your Ebike Torque Arm Install

To complete your torque arm install you can place the spacer included with your torque arm kit between the C Arm and the motor axle bolt. If you do not have room for this spacer, do not install.

Tighten your motor axle bolt with an adjustable wrench. Make sure your wheel is firmly in place and that there aren’t any gaps in the new elements on your axle. If there are gaps, you will need to possibly install the spacer included with the torque arm kit. You may need to place this spacer between the bike frame dropout and the C Arm. Finding the perfect fit might take some trial and error.

Enjoying your powerful yet safe ebike

You now taken steps to help prevent your wheel from flying off of your ebike. Help reduce the amount of torque directly applied to your bike frame by installing a torque arm. or two. The need for a torque arm depends on the dropouts of your bike frame and the power of your ebike. What size wattage ebike are you riding?

Please let me know in the comments if you have any questions.

Ride Safely