MAHLE's M40 mid-drive has borrowed traction control from the car world to keep your rear tyre hooked up on loose climbs — and existing owners get it free, over the air.
MAHLE has pushed a major software-led update to its M40 mid-drive — the German supplier's first full-power motor for electric mountain bikes — headlined by a new traction control system. Borrowing the logic of a car's stability electronics, it watches pedal force, motor data, gear selection and rear-wheel speed, then trims power the moment the back tyre starts to spin on a loose, steep climb.
It arrives alongside two other changes. A new Smart Assist dynamic mode adjusts support to the terrain automatically — easing off on the flat to stop the bike surging, ramping up as the trail kicks skyward — and the Dynamic Overrun is now adjustable. New 2026 bikes get all of it from early April; existing M40 owners receive it as a free over-the-air update from mid-May, according to BikeRadar.
MAHLE M40 by the numbers
Inside the new traction control
The clever part is resolution. The M40 reads its rear-wheel speed 84 times per revolution — roughly every 5 degrees, or about every 3 cm of ground covered — versus the single reading-per-revolution you get from a basic wheel magnet. That lets it spot the tiny acceleration spike of a slipping tyre almost instantly, dial torque back, and (per emtb-test.com) shift peak load into the cranks' 'dead spot' until grip returns.
Two caveats worth knowing for SA trail riders: the system is disabled on descents and has to be switched on manually, so it's a climb-mode aid rather than an always-on safety net. The upside is that, unlike crude older slip-control hacks, it's tuned to keep you moving rather than just cutting the motor dead.
M40 vs Bosch, Specialized & DJI
View data table
| Peak power (W) | |
|---|---|
| DJI Avinox | 1000 W |
| MAHLE M40 | 850 W |
| Bosch CX Gen 5 | 750 W |
| Specialized S-Works | 720 W |
What the reviewers say — and our verdict
Four outlets, one motor
Independent verdicts from across the cycling press — follow each link for the full review.
More punch than the Bosch CX Gen 5
“It delivers more punch than the Bosch CX Gen 5, pairing that with high 48-volt efficiency and a control logic that doesn't turn the rider into a smartphone slave.”
Read the full reviewDetunes, then ramps power back — quietly
“The traction control absolutely stood out in the way it detuned motor power to allow me to keep climbing until traction returned before quickly ramping power back up.”
Read the full reviewWelcome help on the techie stuff
“Techie climbing is more of a chore than a fun challenge and I appreciate all the help I can get.”
Read the full reviewCompact, muscular, lots of potential
“With its compact design and muscular performance, the M40 is an exciting system with loads of potential.”
Read the full reviewThe balance sheet (aggregated from coverage)
- Genuinely useful traction control for loose, technical climbs — detunes then ramps power back smoothly
- Strong numbers: 850 W peak / 105 Nm, beating the Bosch CX Gen 5 on paper
- Light at 2.5 kg and described as quiet 'both up and down'
- Smart Assist finally adds the auto/dynamic mode reviewers wanted
- Full power held to the last battery percent; free over-the-air upgrade for existing owners
- Traction control is climb-only, off on descents, and must be enabled manually
- Sustained maximum output derates after roughly 12 minutes
- Top-tube display 'looks outdated', per E-MOUNTAINBIKE
- No confirmed South African pricing or wide local availability yet
- DJI's Avinox still tops it for raw peak power (1,000 W)
Our compiled assessment from published first-rides, not our own testing: a software update that meaningfully sharpens an already strong motor. The traction-control and Smart Assist additions answer the original M40's two biggest criticisms, and a free OTA roll-out for existing owners is a real plus. Local pricing and availability are the open question.
Tap to vote — see how readers lean
Mahle M40 update: your questions
Will my existing MAHLE M40 get traction control? +
Yes. MAHLE is rolling the update out free over-the-air to existing M40 owners from mid-May 2026; new bikes ship with it from early April.
Is the traction control automatic? +
No. It's a climbing aid that's switched off on descents and has to be enabled manually, so you turn it on when you hit the loose, steep stuff.
How does the M40 compare to Bosch and DJI? +
On paper it beats the Bosch CX Gen 5 (850 W / 105 Nm vs 750 W / 100 Nm) and the Specialized S-Works (720 W), but DJI's Avinox still leads on raw peak power at 1,000 W.
What batteries and range does it offer? +
Two packs — a 534 Wh iM5 and an 800 Wh iM8. MAHLE claims up to 150 km or 2,500 m of climbing from the 800 Wh battery.
Can I buy an M40 e-bike in South Africa? +
Not widely yet. MAHLE is launching through a handful of brand partners and the system is only reaching bikes through 2026, so check with local importers before banking on availability or pricing.
Sources & further reading
- Traction control comes to eMTBs with MAHLE's updated M40 drive-unit — BikeRadar
- MAHLE M40 System — official specs & features — MAHLE SmartBike Systems
- New MAHLE M40 motor gets 850W power and 105Nm torque — MBR
- New MAHLE M40 E-Bike Motor and next-gen eMTBs — E-MOUNTAINBIKE Magazine
- Dissected: The MAHLE M40 eBike System — The Loam Wolf
- MAHLE M40 Review — measured power & climb test — emtb-test.com
The M40 update is the clearest sign yet that the e-MTB motor war has moved from raw watts to software. Traction control and Smart Assist directly answer the two things reviewers dinged the original M40 for — no auto mode, and the usual loose-climb wheelspin — and the fact existing owners get both free, over the air, is a genuine win. It won't out-muscle DJI's 1,000 W Avinox on a dyno, but for steep, rooty, gravelly South African climbs, a motor that keeps the rear tyre hooked up may matter more than peak power. The open question for local riders is availability and price — both still unconfirmed.
