This article is part of our big 2026 motor group test. Click here to read about all 11 systems we tested, discover the latest trends and dive into detailed results from both the lab and real-world testing.
MAHLE are no strangers to the game. As a major automotive supplier, the German manufacturer has more than its fair share of experience with engine components. In the bike world, MAHLE are best known as a key development partner behind the Specialized Levo SL 1.1 and 1.2 motors. But the M40 is aiming higher. This marks MAHLE’s solo debut with a full-power mid-drive motor, and it’s clear they’re not just here to take part — they want to prove they can compete at the sharp end when it comes to performance, integration and system technology. We put the M40 to the test to see whether it lives up to those ambitions or struggles to keep up with the competition.
The MAHLE M40 Motor in Detail – A Debut With Extra Boost
For this group test, MAHLE provided their own white-label platform built around the M40 mid-drive motor. Visually, the drive unit blends in surprisingly discreetly for a motor in this performance class, nestling neatly into the bottom bracket area. Alongside the Avinox, it’s one of the best-integrated full-power motors in the entire test field. According to MAHLE, the motor delivers 105 Nm of torque and up to 850 W peak power. With a support ratio of up to 600%, it’s one of the most powerful systems on paper and is best compared to the S-Works 3.1 in terms of performance. What’s particularly impressive is the weight: at just 2.60 kg, the M40 is the second lightest full-power motor in the test, beaten only by the Avinox. Hats off!
When it comes to batteries, bike manufacturers can choose between a compact 534 Wh variant or a bigger 800 Wh model. MAHLE don’t currently offer a range extender. Charging is taken care of by a 4A charger, which tops up the 800 Wh battery in 4 hours and 8 minutes. With an average charging speed of 3.1 Wh/min, that puts MAHLE in a strong fourth place, just behind Specialized, Avinox and TQ.
Less convincing is the Head Unit+, which sits neatly recessed into the top tube and is designed to provide a clear overview of the motor system.The 1.9” colour display wastes a lot of space due to its thick bezel, offers only low resolution and lacks a distinctive design identity. On the plus side, it shows battery charge status and, across three additional screens, your current speed, motor and rider output, and pedalling cadence. A rubberised button lets you switch between modes and pages with a double click.
However, if you forget to switch the bike off, the system remains powered indefinitely and doesn’t automatically drop into a standby mode. Holding down both buttons brings up a submenu where you can fine-tune the assistance levels, peak power, maximum torque, acceleration and overrun for each mode. Overall, though, the Head Unit feels underdeveloped and not quite ready for prime time.
The MAHLE Duo Remote leaves a better impression and can be swapped out for the wireless Trio Remote if preferred. The rubberised Duo Remote offers good tactile feedback and feels solid, but it’s still wired to the motor system, which makes it look a little bulky. Every time you switch modes, an audible signal confirms the change, giving you clear feedback on which support level you’re in.
The MySmartBike app is the interface between the rider and the MAHLE system. It allows you to track rides, provides range estimates and offers navigation for pre-loaded routes – although only when there’s mobile signal. You can also connect a heart rate monitor, enabling the drive unit to automatically adjust support levels based on your current heart rate and physical effort. To do this, you’ll need to enter your maximum heart rate once. In practice, however, this feature only works to a limited extent. In our test, with a maximum heart rate set at 200 bpm, the motor only switched to the medium support level at around 130 bpm, and only moved to the highest level under genuinely heavy effort and a high pulse.
Unfortunately, that’s more or less where the options end. Key features like a digital motor lock are missing, and the most critical drawback is that support modes and overrun can’t be customised via the app – only through the display. While this might be beginner-friendly, it severely limits flexibility and falls short of the adaptability we expect from modern motor ecosystems. Overall, the app feels solid but underdeveloped, and the same goes for the display. Both cover the basics but miss too many opportunities. For a motor aiming at the premium segment, it’s simply not enough.
| Parameter | Our measurement | Manufacturer’s spec |
|---|---|---|
| Motor weight (kg) | 2.60 kg | 2.5 kg |
| Battery capacity (nominal, Wh) | 748.8 Wh | 800 Wh |
| Charge time (0–100%) | 4 h und 8 min | – |
| Support ratio (%) | – | 600 % |
| Max power output (W) | – | 850 W |
| Max torque (Nm) | – | 105 Nm |
| Range* (km) | 22.3 km | – |
| Vertical range* (metres climbed) | 1,739 hm | – |
*All values were measured on the same test track with an average incline of 8.5%, using the maximum support mode, a consistent rider output of 150 watts, rider weight of 72 kg, and standardised tyres: MAXXIS HighRoller (DD, MaxxGrip) up front and MAXXIS Minion DHR II (DD, MaxxTerra) on the rear.
The MAHLE M40 motor on test
The MAHLE M40 motor on the trail
When you power up the system, the MAHLE M40 offers three support modes: Level 1, 2 and 3. On the road, the motor responds with striking sensitivity when setting off. Even the slightest pressure on the pedals is enough to trigger a reaction. Despite this, the M40 remains easy to control after take-off, especially in tight switchbacks where the bike steers smoothly through the turns.
Things look a bit different when starting on an incline: here, you’ll need to put in a surprising amount of effort before the motor kicks in. While the Automatic Hill Brake helps prevent the bike from rolling backwards on steep ramps, the power delivery feels noticeably delayed in this situation.
On steep climbs in the highest support mode, the M40 feels just as powerful as the S-Works 3.1 drive, although it delivers a bit less punch at lower cadences. The MAHLE motor pulls strongly, gets you reliably over steps and ramps, but feels less natural than the Bosch CX or Avinox, both of which deliver their power in a more controlled and refined way.
Traction on the trail is impressive, with the M40 keeping the pedals nicely planted underfoot, which helps you keep the bike moving forward even on rough terrain. When things get technical, the Dynamic Overrun comes into its own. Even if you briefly stop pedalling, the motor continues to push gently. That gives you added confidence when tackling tricky climbs and technical uphill sections.
In other riding situations, however, the MAHLE M40 still leaves room for improvement: if you approach a steep climb in a small gear at a high cadence, the M40 drops into a noticeable power dip and has to significantly rein in its output towards the top. The fade-out at the 25 km/h cut-off is also rather abrupt. And what about the sound? On the way up, the MAHLE sits roughly on a par with a Bosch CX acoustically—audible, but not intrusive. Once the trail points downhill, however, the impression changes: the motor develops a clearly audible rattle, which slightly detracts from an otherwise solid ride feel.
The MAHLE M40 motor on the test bench
On the test bench, the MAHLE M40 came across as notably restrained at rider inputs of up to 200 W, offering only modest torque and operating well short of its capabilities in both power delivery and support. It couldn’t be pushed any further and eventually shut down with an error – something we didn’t encounter on the trail, so we’re chalking it up to the artificial nature of the test environment. On the plus side, the motor scored well for efficiency in the measured areas, placing it right at the top of the field alongside the maxon.
The derating behaviour is also commendable: after a steady drop of around 70 W over the first eight minutes, the motor maintained consistently high output without further performance loss. It’s worth noting that the measurements were only possible at the lower rider input of 200 W. In terms of noise, the MAHLE M40 tends toward the high-frequency end. At lower cadences, it develops a relatively tonal hum and sits in the middle of the pack in terms of noise. As you climb faster and the cadence increases, the sound becomes more multi-tonal and hissing, reminiscent of a quiet turbine. Despite that, it’s still one of the quietest motors in the group, with its high pitch cutting through ambient noise more than its volume.
Tuning tip for the manufacturer: A better Head Unit+, more functions in the app, and more dynamic support modes would make the MAHLE feel more modern and versatile.
Who Should Take a Closer Look at the MAHLE M40 Motor – and Who Should Look Elsewhere?
The MAHLE M40 is an appealing choice for riders seeking a lightweight, high-performance motor that combines rapid charging with immediate, punchy power delivery. You’ll benefit from its sensitive response and strong pull. On the other hand, it’s less suited to trail enthusiasts who prioritise a natural ride feel, dynamic support modes or extensive app customisation. It’s also a pity that there are currently very few bikes available with the M40, which limits both choice and versatility.
Conclusions About the MAHLE M40 Motor
The MAHLE M40 marks an exciting first step for the German brand into the full-power motor segment. In terms of performance, design and weight, it doesn’t need to hide from the best motors on test – in fact, it’s among the lightest and most powerful in its class. Out on the trail, however, it can’t quite keep pace with the competition: power dips at high cadence and a rattling noise on descents hold it back from a top-tier result. That said, the M40 is a solid, forward-looking motor that shows MAHLE have real potential to become a serious player in the market – especially if they refine the app, display, support modes and overall ride feel.
Tops
- Refined response and precise control in tight switchbacks
- Solid average charging time
- Strong climbing power
- Excellent power-to-weight ratio
Flops
- Power dips at high cadence
- Weak display and limited app functionality
You’ll find all further information on MAHLE’s website.
The test field
For an overview of the test field head to Our big eMTB Motor Comparison – 15 eMTB Motors on Test
All motors in test:
Avinox M1, Bosch Performance Line CX Gen5, Bosch Performance Line CX-R, Bosch Performance Line SX, FAZUA Ride 60, Mahle M40, maxon Air S, Pinion MGU E1.12, Shimano EP801, S-Works 3.1, TQ HPR60
Words: Benedikt Schmidt Photos: Peter Walker
