Increase torque via update - how far can an e-bike motor be pushed by software?

More torque via app update: What sounded like futuristic music just a few years ago has become a reality for modern e-bikes. For e-bikes with the Bosch BDU38 drive system, the maximum torque can now be configured via software to up to 120 Nm. The update is installed "Over the Air" (OTA) via a smartphone app - without a workshop visit, without new hardware.

By Vincent Augustin 4 minutes read time

About the author Vincent Augustin

Vincent founded MYVELO together with Fabian. The two share a long-standing passion for cycling. Together they have cycled thousands of kilometers and fought for victories in the German racing bike league. The idea of founding MYVELO arose from their many years of experience and knowledge of what makes a good bike. Find out more about MYVELO now

Published: May 18, 2026 | Updated: May 19, 2026

How is that technically even possible? Why can a motor suddenly become more powerful even though nothing mechanical has been changed? And what are the consequences of more torque for the chain, sprocket, and the entire drivetrain?

Why an OTA update is even possible for e-bikes

Modern e-bike drives are no longer purely mechanical systems. They consist of:

Electric motor
Power electronics
Sensors
Firmware
Communication modules
Battery Management System (BMS)

The actual character of the motor is now largely defined by software. The hardware often has power reserves that the manufacturer deliberately releases conservatively.

An OTA update works similarly to smartphones or electric cars:

The new firmware is downloaded via the app
The smartphone connects to the bike via Bluetooth
The motor control receives new parameters
Torque, assistance, or riding modes are adjusted

The physical motor remains identical – only the control strategy of the electronics is changed.

Why manufacturers often artificially limit motors

An e-bike motor is not always operated at its absolute physical limit. There are several reasons for this:

1. Durability

Higher load means:

more heat
higher forces on bearings
greater stress on gears
higher stress on the freewheel

Manufacturers deliberately incorporate safety reserves.

2. Noise development

A more aggressively tuned motor can:

become louder
vibrate more
feel rougher

Many systems are therefore throttled for the sake of comfort and smooth running.

3. Battery protection

More torque usually means:

higher current peaks
faster battery discharge
greater thermal stress on the cells

4. Model policy

Software enables manufacturers to offer different performance levels on the same hardware basis.

A motor may technically be capable of 120 Nm, but is delivered with only 85 or 100 Nm, depending on the model.

How an e-bike motor is dimensioned

An electric motor simplified consists of:

Rotor
Stator
Windings
Magnets
Power electronics

Crucial for torque are, among other things:

Current strength
Magnetic field
Winding design
Cooling
Gear ratio in the gearbox

Basically: M = F x r

Torque thus arises from force and lever arm.

In an e-bike motor, the force is generated electromagnetically. More current flow usually means more torque - but only up to certain limits.

The physical limits of an e-bike motor

Even if software can change a lot: physics remains non-negotiable.

Heat development

The biggest limiting factor is usually temperature.

More power generates more waste heat:

P_loss = I^2 x R

This means:

double the current generates four times the heat loss
windings can overheat
magnets lose efficiency when hot
electronics age faster

Therefore, modern motors have temperature sensors and protection algorithms.

Material stress

More torque means higher forces on:

Gears
Bearings
Axles
Freewheels

Particularly compact mid-drive motors already operate with enormous loads in a small space.

Battery limitations

The battery also sets limits:

maximum current output
cell chemistry
internal resistance
temperature

A motor can only draw as much power as the battery and electronics can deliver.

Why 120 Nm is impressive

For comparison:

classic trekking e-bikes: 50–75 Nm
powerful EMTB systems: 85–95 Nm
120 Nm is already in the range of small motorcycles

The enormous torque is particularly evident:

on steep climbs
at low cadence
when accelerating
with heavy luggage
in technical terrain

Cargo bikes and e-MTBs in particular benefit significantly from this.

The downside: More wear and tear

More torque almost always means more stress on the drivetrain.

The chain suffers first

The bicycle chain is one of the most heavily stressed components.

High motor power leads to:

greater chain tension
higher material stress
faster elongation wear
increased risk of chain breakage

Especially with incorrect shifting under load, the stress increases massively.

Sprockets and cassettes wear out faster

Sprockets are also subjected to greater stress:

higher surface pressure
faster tooth wear
material fatigue

Particularly small sprockets suffer under high torques.

Gears and rear derailleur

More motor power can also be problematic for:

shift ramps
derailleur springs
freewheels
hub gears

This is why modern systems often integrate so-called "Shift Detection" functions. The motor briefly reduces power when shifting.

Why software is becoming more important than pure hardware today

The trend is clear: The future of modern e-bikes is increasingly software-defined.

Via firmware, it is now possible to change:

Assistance characteristics
Response behavior
Range
Dynamics
Torque limits
Recuperation functions
ABS systems

The actual "riding experience" is increasingly created by algorithms.

Does more torque automatically mean better riding?

Not necessarily. Extremely high torques can also have disadvantages:

more difficult to modulate
higher tire wear
reduced range
greater component wear
less stable riding behavior

For many riders, harmonious power delivery and fine modulation are more important than maximum Newton meters.

Conclusion: The OTA update shows how digital modern e-bikes have become

The fact that an e-bike system can be configured to 120 Nm via an app impressively demonstrates how heavily software-controlled modern e-bikes have become.

The hardware often possesses considerable power reserves that are only unlocked by firmware. But more torque is never free:

Heat increases
Wear increases
Battery and drivetrain are subjected to greater stress

The actual challenge is therefore not just to provide as much power as possible - but to make it permanently controllable, efficient, and reliably usable.

This is precisely where the quality of an e-bike is no longer determined by the motor alone, but increasingly by the software behind it.