Posted by Paul Hoyle on 29th Sep 2025
Motor Guide Contents
The motor is the heart of an electric bike, transferring power from the battery to the rear wheel, propelling you forward.
An e-bikes performance is determined by two factors:
- Max power output (Watts) - The peak, short burst power that the motor can deliver.
- Torque (Nm) - The push that the motor gives to help turn the pedals. Most people judge this as the benchmark, as to much of a “kick” and “push” it can give you up the climb when in the highest setting.
Types of Motors
There are 2 prominent types of drive units we regularly see on electric bikes.
Full Power
- 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 duty bikes with larger batteries.
- They deliver 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 natural power delivery.
- 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.
| Feature | Full Power Motor | Lightweight Motor |
|---|---|---|
| Peak Power | ~600 W | ~300–450 W |
| Torque | 85 Nm+ | ≤ 60 Nm |
| Weight | 2.5 kg+ | ≤ 2.0 kg |
| Climbing Performance | Excellent (with overrun) | Good on moderate climbs, more user input required for steeper climbs |
| Ride Feel | Punchy, high-assist | Natural, rider-like |
| Bike Handling | Slightly less agile | More agile and playful |
| Best For | Steep/technical terrain | Flow trails, mixed rides |
Important questions to consider when choosing a motor
1 - What terrain are you riding?
The terrain you ride most often is the best starting point when deciding which e-MTB motor suits you. Electric bikes unlock new possibilities on the trails and tracks, opening up routes you couldn’t reach before, extending ride distances, and making climbs far more manageable.
- Full-Power Motors
Best for riders tackling steep climbs, demanding terrain, and technical features. These deliver maximum torque and support when the gradient gets tough. - Lightweight Motors
Designed for riders who want a more natural pedalling feel across varied terrain. They give you enough assistance to extend your range and smooth out climbs, without removing the workout or ride feel you’d expect from a traditional mountain bike.
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 often ride alone, or 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 help flatten the climbs and make it easier to get back in the saddle and build up fitness.
- If 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.
- It's worth remembering, no matter your level of fitness you can always reduce the level of your assistance at any point to prolong the battery life, and increase your fitness levels.
4 - What do you value from your e-bike ride
- If you desire a more traditional, natural, 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 doesn't feel over-powering.
- However if you are simply looking for a bike that can deliver maximum power to complete big climbs and assist you over technical features a more powerful system is likely better suited to your needs.
Please note:
This guide by MTB Monster is designed to help you understand the technical aspects of bike components. The information is drawn from industry knowledge and the experience of our team. While we strive for accuracy and unbiased comparisons, occasional errors or updates may occur. We always recommend doing your own research before making a final purchase decision..
Need any further help in choosing your next bike? Drop us a line on 01254 959345, or alternatively fill out the form below. We'd be glad to help.
