EMTB Motor Guide | Choose The Perfect One (2025)

Latest Posts ! EMTB Motor Guide | Choose The Perfect One (2025)
EMTB Motor Guide | Choose The Perfect One (2025)

Posted by Paul Hoyle on 13th Jan 2025

Electric Mountain Bike (EMTB) Motor Guide
The motor is the heart of an electric mountain bike, functioning as the drive unit which transfers power from the battery to the trail and drives your e-bike forward. Motors are typically graded and measured on their Max Power Output, and the Newton Meters of Torque (Nm) produced. The max power output is measured in Watt (W) output, which is the peak power transferred through a wheel in a short space of time. Whilst Nm is the measure of continuous power which the motor produces. It's also important to note all UK motors are limited to a top speed of 15.5mph, no matter the power output of the motor.

This guide explains the 2 prominent motors we see in the UK and important questions to consider when choosing a motor. 

Types of Motors

Full Power

There are 2 prominent types of drive units we regularly see on electric bikes. Firstly full power high Watt output - high Nm drive units typically outputting 600W through the wheel and 85Nm (and up) of continuous torque. These motors are typically heavier, weighing 2.5kg and up. And are typically fitted to heavier bikes with larger batteries. These bikes are generally considered to be the traditional form of EMTB, delivering a punchy surge of power up steep climbs.. whilst being less manoeuvrable on the descents. These motors often feature overrun, which provides an extra surge of power when a pedal stroke ends. Which for example can drive you over technical features on climbs.  

Lightweight

The second style of motor we see are lightweight drive units. These motors are constructed to be low in weight - and provide a more natural power delivery opposed to the surges in power delivered from full system electric bikes. These motors typically aim to mirror a rider's pedal inputs to create a seamless pedalling experience akin to a mechanical bike. Lightweight motors typically output no more than 60Nm and weigh in at 2.0 KG or less, to aid in a bikes natural performance on the trail.  

What are the important questions to consider when choosing a motor ?


1 - What terrain are you riding? 

The terrain you are expecting to regularly ride is a great starting point to determine which motor is best for you. Electric bikes open up many more possibilities on the trails, they open up new routes, new riding distances and propel riders up climbs they once pushed their way up.

If for example your local trail and the majority of terrain you ride features large amounts of steep climbs with lots of technical features, a higher torque motor with overrun is likely the best choice, to power you through technical climbs. However if your local trail is made up of predominantly flowy sections, a less powerful motor will likely be more suitable.

2 - Who you ride with

Who you regularly ride with is an excellent indicator, concerning the drive unit most ideal for you. If your group all ride full power eMTB’s and regularly climb ascents in a higher output mode, opting for a lightweight motor is likely going to leave you at the back of the pack and far more fatigued.

On the other hand if you ride with people who either ride with lightweight motors or mechanical bikes, a lightweight motor is likely an excellent choice. Because you can reliably maintain a cadence to match those around you.

3 - Your physical fitness

Many riders opt for a full power electric bike because they flatten the climbs and make it easier to get back in the saddle and build up fitness. Mountain biking is an incredibly physically demanding sport and long climbs are very exhaustive even on the most experienced riders. If for example you are just getting back into the sport and don't have a high level of fitness.. a higher power motor is going to be far more supportive and forgiving on the climbs compared to a lightweight motor.

However if you desire more of a challenge from your rides a lightweight motor will demand more input from the rider and thus provide a more intensive workout from those who perhaps are more physically fit.

4 - What do you value from your electric mountain bike

If you desire a more traditional mountain bike experience from your time in the saddle, lightweight motors are designed to deliver this. A lighter weight keeps the overall weight of the bike down, maintaining agility and manoeuvrability, whilst the assistance delivered doesnt feel over-powering, mirroring a riders inputs.

However if you are simply looking for a bike to deliver maximum power to complete big climbs and assist you over technical features a more powerful system is likely better suited to your needs. 

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