Our Guide To Installing A Torque Arm On Your Electric Bike

If you've decided to convert your bike into an electric one, figuring out how to install all the components on your bicycle frame can be overwhelming. 

Installing a torque arm is pretty simple as long as you have some axle nut tools and a spanner on hand to tighten the torque arm up. Most fit into the frame dropout of your bike frame with ease.

We've put together a short guide below which will explain the exact purpose of a torque arm and how to install them on both a rear hub motor and a front hub motor.

What Does A Torque Arm Do On An Electric Bike?

Torque arm installation is very important on electric bikes since it stops damage to frame and forks on an electric bike.

You will mostly find that e-bikes with a 250-watt motor and above need to have a torque arm, the purpose of this component is to make the power transfer from the motor to the wheel smoother and less harsh on the e-bike.

How To Install A Torque Arm On The Front Wheel 

Installing a torque arm onto your front wheel is easy as long as you have your torque tools on hand like a wrench. 

We've listed some easy to follow steps below. 

• Step one - Start by turning the motor wheel on the bike upside down, one torque washer will be installed on the hub and the other on the flat washer on the inside, tighten the axle nut with a wrench to make sure they're secure, tighten to about 40Nm. 
• Step two - Next assemble the splined pieces on the motor cable side for ease of use and bolt on the longest part of your torque arm to the outside splined
• part. 
• Step three - Position the torque levers and the splined parts so that the main levers are perpendicular, this angle keeps the torque pressure off your dropouts on the electric bike. 
• Step four - Lastly use the hose clamp to secure the arm to the fork.

How To Install A Torque Arm On The Rear Wheel 

To install a torque arm on a rear wheel is a little more complicated than on a front wheel, but follows a similar process which we will list in detail below.

• Step one - Loosen the axle nuts on your wheel then check if you need to space out your rear forks any further with washers. Make sure the distance between your dropouts is around 135mm. 
• Step two - Turn the wheel upside down and push it into the dropouts, tighten it to 40Nm, and then we can start to install the torque arm. 
• Step three - Take the splined pieces and assemble them over your motor axle, choose if you want to install them on the gear side then make sure the levers are perpendicular at 90-degrees. 
• Step four - Use the hose clamp to secure the arm to the fork and double-check the wheel alignment due to the C washers.

Frequently Asked Questions About Installing Torque Arms 

Why do I have to have a torque arm on my electric bike? 

Torque arms are extremely important in electric bike conversions since the frame of a regular bike is not meant to handle the electrical components and strength of a motor. It essentially protects the dropouts on the frame from damage. 

Do I need to put torque arms on my shop brought electric bike? 

No, most e-bikes brought as e-bikes will already have a torque arm in place to protect the frame. 

Should I use torque arms for my e-bike conversion if I have an aluminium fork?

This depends on the motor wattage, under 500W, then you will probably be okay without a torque arm if you have aluminium dropouts, but above 500W you don't want to risk ruining your frame.

Final Words 

Overall, torque arms are essential to install on both sides of your bike preferably when undertaking an electric bike conversion. They help to protect your frame dropouts from the torque of the motor which would otherwise cause damage, we would always recommend installing torque arms if your motor has a wattage over 250W - 500W.