Smart Assist & Traction Control: Intelligent Features for the M40
The M40 System continues to evolve as MAHLE SmartBike Systems expands its functional ecosystem with new intelligent features while refining existing ones. Built around a compact and lightweight mid‑drive architecture, the M40 is designed to adapt to real mountain bike conditions through software‑driven intelligence, working discreetly in the background and always centred on rider input.
The system now combines newly introduced functionalities with established features, all working together to deliver a riding experience that feels natural, predictable and fully connected to the terrain.
New intelligent features: Smart Assist and Traction Control
The latest evolution of the M40 System introduces two new functions that further enhance adaptability and control on the trail: Smart Assist and Traction Control. Both have been developed to react automatically to changing conditions and rider input, without the need for manual activation.
Smart Assist: Context-aware support that matches you
Smart Assist has been developed to address a core challenge of mountain biking: rapidly changing gradients and trail conditions that traditionally force riders to switch assistance modes frequently.
Instead of relying on fixed levels, Smart Assist continuously adapts motor support in real time based on rider input power, bike speed, terrain gradient and, in certain cases, the selected gear. With a single mode, the system covers everything from flat sections to steep and technical climbs.
The behaviour of Smart Assist can be adjusted via the app or HMI to suit individual preferences. Riders can define assistance ratio, maximum power and acceleration response, creating profiles that range from almost muscular riding to comfort‑oriented support. In all configurations, assistance always requires active pedalling; power is never delivered without rider input.
By delivering only the power required in each moment, Smart Assist not only improves ride quality and continuity, but also optimises energy consumption compared to fixed high‑support modes.
Traction Control: Climb with confidence
Traction Control is designed to maintain progress on wet, loose or slippery terrain by precisely managing motor output at the rear wheel. Rather than reducing power indiscriminately, the system regulates torque only when traction thresholds are exceeded.
The rear wheel speed sensor measures wheel position 84 times per rotation, allowing the detection of even minimal traction losses. These signals are combined with motor data, rider torque, cadence and gear ratio, enabling the system to calculate the torque actually transmitted to the ground.
When slip is detected, an in‑house MAHLE control algorithm adjusts motor torque in milliseconds, smoothing power delivery and preventing sudden spikes that cause wheel spin. When grip is sufficient, the function remains inactive and invisible.
Traction Control integrates seamlessly with the rest of the M40 ecosystem, reinforcing stability, climbing efficiency and predictability in technically demanding situations.
Established M40 features: Dynamic Overrun and Auto Hold
Alongside these new additions, the M40 System continues to rely on proven functions that are already part of its core DNA: Dynamic Overrun and Auto Hold. These features have been designed from the outset to operate intuitively, without buttons or manual activation.
Dynamic Overrun: Seamless momentum when you need it most
In the context of eBike systems, overrun refers to the continuation of assistance after the rider stops pedalling, limited by regulation to a maximum distance of two metres. In technical terrain, this brief impulse can be decisive.
Dynamic Overrun adapts continuously to the situation instead of behaving in a fixed manner. Using speed, rider torque and cadence behaviour, the system determines both the intensity and duration of the overrun dynamically.
Activation is entirely pedal‑driven. The strength of the final pedal stroke defines the impulse, while the cadence pattern when stopping determines how long it lasts — or whether it is cancelled altogether. After a short learning phase, riders can intentionally use or avoid overrun through pedalling technique alone.
For riders who do not encounter such terrain frequently, Dynamic Overrun can be limited or deactivated via the app or HMI settings.
Auto Hold: Hold firm, launch smooth
Auto Hold is an automatic hill brake designed to simplify stopping and restarting on steep climbs. When the system detects that the bike is stationary on an incline, it automatically applies the rear brake to prevent rolling backward.
Input from the HMI accelerometer, speed sensor and torque sensor allows the system to detect this condition reliably. When the rider begins to pedal again, Auto Hold releases the brake and provides a controlled start‑assist impulse. This makes it easier to place the second foot on the pedal and start smoothly, even on very steep gradients.
As with all M40 functions, Auto Hold operates automatically, without any button input.
A balanced system architecture for modern eMTB design
All four features are built on the foundation of a compact and lightweight system architecture designed specifically for modern eMTBs.
Depending on battery choice, the complete M40 System weighs 5 kg with the IM5 battery (534 Wh) or 6.2 kg with the IM8 battery (800 Wh). The motor unit itself weighs just 2.5 kg, contributing to a balanced power‑to‑weight ratio that preserves agility and handling.
Despite its compact size, the system delivers up to 105 Nm of torque and reaches a peak power output of 850 W between 80 and 100 rpm, the cadence range most commonly used in mountain biking. This ensures strong support exactly where riders need it most, without compromising control.
Configurability that reflects each brand’s identity
While capable of providing up to a 600% assistance ratio, the M40 System is defined more by how it delivers power than by raw output figures.
MAHLE SmartBike Systems enables OEMs to configure assistance ratios, power curves, acceleration behaviour and dynamic response, allowing each brand to embed its own DNA into the final riding experience. The system can be adapted to different riding concepts, suspension layouts and component choices, ensuring coherence between mechanical platform and software behaviour.
This flexibility makes the M40 suitable for a wide range of eMTB applications while preserving a consistent, natural ride feel.
A unified ecosystem in constant evolution
Smart Assist, Traction Control, Dynamic Overrun and Auto Hold are not isolated functions. They operate as part of a unified ecosystem, sharing sensor data and responding to rider input as a whole.
All interventions are triggered through pedalling and interaction with the bike, not through buttons or menus. After a brief adaptation period, the system becomes intuitive, allowing riders to stay focused on line choice, balance and rhythm.
The M40 System continues to evolve, integrating new intelligence, refining existing functions and expanding its capabilities, always with the same objective: to adapt to the rider and the trail, not the other way around.
