Mahle M40 Review

The Mahle M40 is a powerhouse, throwing down over 800 watts of peak output—it’s not just taking on the big dogs from Bosch and Shimano, it makes them look dated on paper. We tested whether the M40 is the new benchmark for full-power e-MTBs.

The current trend is crystal clear: the market is asking for more punch, and Mahle is delivering. In our standardized test protocol, we coaxed the M40 into putting out a stout 810 watts of output (with 180 W input). That means the M40 kicks noticeably harder than a 5th-gen Bosch CX (~700 W) and runs in the same league as the Specialized 3.1. The Avinox M1 system can do even more, but if we’re being honest, you’re then entering territory that often just isn’t relevant out on the trail in real-world riding.

Particularly impressive: the M40 hardly needs any rider input to flex its muscles. Even with light pressure on the pedals it delivers a serious shove and already hits peak output at a sporty but very rideable cadence of 85 rpm. Shimano, maxon, or Avinox motors in particular need a noticeably higher cadence to unlock full power. Bosch, on the other hand, manages that with the CX Gen 5 at around 70 rpm at the cranks.

Despite the noticeable power boost over Bosch’s competition, the M40 is a bit of a surprise when it comes to range. With the 800 Wh battery (weight: approx. 3,900 g), we logged 1,952 vertical meters in the highest assist mode. After that, the motor still cranks out another 170 vertical meters, albeit with significantly reduced power.

That’s almost a dead match to the Bosch system (800 Wh), even though the Mahle rider hits the summit noticeably faster. One reason for this efficiency is the 48-volt system, which has lower transmission losses compared to classic 36-volt systems. On top of that, the motor seems perfectly tuned for cadences around 80 rpm.

Mahle sends the M40 into the ring with a software package that shows real off-road know-how. The traction control in particular stands out:

Where there’s light, there’s shadow—or at least some noise. The M40 is always present on the climb. As cadence ramps up, the pitch gets higher, but it stays within the usual range for full-power motors.

Pointed downhill, the Mahle delivers the gear rattle that’s typical of mid-drive units. It’s not as intrusive as the notorious clatter of a Shimano EP801, but it’s still clearly audible out on the trail.

Mahle positions the M40 as a sporty system. At 2,700 g, the motor is about 200 g lighter than a Bosch CX, but noticeably punchier than true light motors like the Maxon Drive Air S.

It’s currently spec’d in on bikes from smaller manufacturers like Kristall, Abums, or Kraftstoff. Mahle lists all models running their motor on their own website via a filter function. Anyone who already owns one of these bikes can now update the motor for free via the app. The software update also unlocks features like traction control and Auto-Hold for motors that have already shipped.