Pedal assist on e-bikes: How it really works

E-bikes are booming – yet one key topic often remains unclear: How exactly does the pedal assist work? Many know that a motor provides support, but not when , how strong , or what factors it depends on . This article addresses this very point, explaining clearly, technically accurately, and practically how pedal assist on an e-bike actually works .

By Fabian Huber 3 minutes read time

About the author Fabian Huber

Fabian founded MYVELO together with Vincent. 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: April 8, 2026 | Updated: April 9, 2026

What does pedal assist mean on an e-bike?

An e-bike – or more precisely, a pedelec – doesn't ride itself . The motor only provides assistance when you pedal. This assistance is called pedal assist .

👉 Important:

No pedaling = no engine power
The assistance legally ends at 25 km/h.
The motor output is a maximum of 250 watts continuous power.

This clearly distinguishes the pedelec from e-mopeds or S-pedelecs.

The three most important sensors – the heart of the pedal assist

Sensors are used to tell the motor when and how much assistance to provide. Modern e-bikes usually use a combination of these three:

1. Torque sensor – the most important sensor

The torque sensor measures how hard you pedal . The more force you apply, the more assistance the motor provides.

✔ very natural driving feel
✔ particularly efficient
✔ Standard on Bosch, Shimano, Brose, Yamaha

👉 Ideal for:

sporty driving
Mountains & Tours
long range

2. Cadence sensor

It recognizes that the pedal is being used – but not how hard . The engine output remains fairly constant.

✔ cheaper
✖ less sensitive
✖ higher energy consumption

👉 Frequently used at:

simple city e-bikes
affordable models

3. Speed sensor

Measures the current speed and ensures that:

It stops at 25 km/h
the support remains consistent

It always works in combination with other sensors.

How does the e-bike decide how much assistance to provide?

The motor control combines sensor data with the selected support mode .

Typical modes are:

Eco → low support, maximum range
Tour / Normal → balanced
Sports → strong support
Turbo / Boost → maximum power

👉 Example:

You accelerate hard in turbo mode.
→ Sensor detects high torque
→ Motor provides strong support

This creates the feeling of being "suddenly much stronger" – without the bike actually moving on its own.

Support levels vs. percentages

Many manufacturers specify the support level as a percentage :

Eco: approx. 50–70%
Tour: approx. 120–150%
Sports: approx. 200%
Turbo: up to 340% (e.g. Bosch )

👉 This means: If you pedal with 100 watts, the motor can deliver up to an additional 340 watts in turbo mode.

Why does pedal assist feel so different depending on the motor?

Not all e-bike motors ride the same. Differences arise from:

🔧 Engine position

Mid-engine
✔ Direct, natural driving feel
✔ optimal power transmission
rear engine
✔ sporty
✔ Good feeling of acceleration
Front engine
✖ less harmonious
✔ inexpensive

💡 Tip: What is the difference between a mid-engine and a rear-engine?

⚙️ Software & Voting

The engine software decides:

how quickly the engine responds
how soft or sporty the support is
how natural the driving experience feels

👉 That's why a Bosch motor rides differently than a Shimano or Brose system – despite having the same wattage.

Pedal assist and range – the direct relationship

The stronger the support, the higher the power consumption.

Influencing factors:

Support level
Own contribution
Weight
Distance & Gradient
Cadence

💡 Tip: A high cadence (70–90 rpm) relieves the motor and saves battery power .

When does the pedal assist engage – and when does it stop?

The support:

It usually starts after 1/4 to 1/2 a crank revolution.
It ends gently at 25 km/h.
The voltage can be briefly reduced during shifting (shift sensor).

👉 Modern systems operate with virtually no delay.

Common myths about pedal assist

❌ "The e-bike drives itself"
✔ No – no support without pedaling

❌ “More watts = faster”
✔ No – speeds faster than 25 km/h are only possible under your own power.

❌ “Riding an e-bike is not a sport”
✔ Studies show: Pulse and calorie consumption are comparable to normal cycling – often even higher, because you ride for a longer time.

Conclusion: This is how pedal assist really works

The pedal assist is not a trick , but a sophisticated interplay of sensors, motor, and software. It amplifies the rider's own effort instead of replacing it – this is precisely what makes modern e-bikes so efficient, natural, and versatile.

👉 Those who understand how the support works can: