How light can a full power eMTB really be?
For years, full power eMTBs have followed a clear pattern: more power meant more weight. Bigger motors, larger batteries and reinforced frames pushed complete bikes well beyond 23 kg.
That trade off is now being challenged.
During a testing session at Messingschlager, one eMTB equipped with the MAHLE M40 System came in at just 17.2 kg well below what most riders associate with this category.
This wasn’t a special build or a one off concept, but a complete bike designed for real trail riding.
So the question is no longer whether full power eMTBs can be light.
It’s how that level of weight becomes possible.
Rethinking weight in the full power category
Weight is not just a number on a scale. On the trail, it defines how a bike feels.
A lighter full power eMTB changes the riding experience in very practical ways: It feels more agile in tight and technical sections, reacts faster to rider inputs, reduces fatigue on long rides and brings the handling closer to a non assisted bike, making the experience more intuitive from the first pedal stroke.
This is where the category is evolving. Riders still expect strong support for steep climbs and demanding terrain, but they are increasingly looking for bikes that feel precise, responsive and easy to handle not just powerful.
Where weight savings actually come from
Reducing the weight of a full power eMTB isn’t about a single component. It’s about how the entire system is designed and integrated.
A lighter drive unit without sacrificing performance
At the centre of that approach is the M40 drive unit, delivering 105 Nm of torque and up to 850 W of peak power, while weighing only 2.5 kg
What makes the difference is not just the numbers, but how that performance is packaged. A lighter, more compact drive unit gives bike designers more freedom to work with from frame layout to overall bike balance.
Instead of dictating a heavier structure, the system makes it easier to develop bikes that feel consistent, well proportioned and easier to handle on the trail.
A system designed to stay light
The motor is only part of the equation.
The M40 is designed as a complete system, where battery, electronics and interfaces work together as a whole. With the iM5 battery (534 Wh), the full system stays around 5 kg, keeping the overall package remarkably compact for a full power setup.
This approach opens up more possibilities when designing the bike. Integration becomes cleaner, weight distribution more balanced, and engineers have greater freedom to refine geometry and suspension without being constrained by the system itself.
Compact design, real impact
Another important factor is how compact the system is.
A smaller, more integrated motor allows engineers to:
- Reduce material in the frame
- Optimise suspension behaviour in full suspension bikes
- Avoid unnecessary structural reinforcement
The result is not just a lighter bike, but one that feels more natural and easier to handle on the trail.
The 17.2 kg benchmark: why it matters
Seeing a 17.2 kg full power eMTB is significant for one reason: it changes what riders can expect from this category.
Until now, full power bikes were almost always associated with a certain weight range. That expectation shaped everything from bike design to riding style.
This example shows that those limits are no longer fixed.
It’s not just about reaching a lower number on the scale, it’s about opening the door to a different type of full power eMTB, where weight is no longer the defining characteristic.
A new balance between power and agility
The full power category is evolving.
Instead of pushing only for higher torque or bigger batteries, the focus is shifting towards balance: delivering strong performance without compromising ride quality.
Lightweight full power systems are part of that shift. They open the door to bikes that feel more agile, more intuitive and closer to the riding experience many users are looking for.
And the 17.2 kg example shows that this shift is already here.
