In the context of bicycles and e-bikes, gear ratio describes the distance a bicycle travels in one complete crank revolution . It is usually given in meters per pedal revolution (m/rev) .
Simply put: 👉 The unfolding shows how "far" you can get with one kick.
Why is development important?
Gear ratio is a key measure for practically evaluating a bicycle's gearing . It helps to understand:
how fast a gear really is
how light or heavy a gear feels
whether a gear system is designed more for mountains, everyday use or speed
Especially with e-bikes, the gear development is crucial because, together with motor assistance, it determines how harmonious the riding experience is.
Calculation of the development
The development results from three factors:
Chainring teeth (front)
Rear sprocket teeth
Wheel circumference
The basic formula is: 👉 Development = (Chainring teeth ÷ Sprocket teeth) × Wheel circumference
Example:
→ Unfolding = (50 ÷ 10) × 2.10 = 10.5 m
This means: 👉 With one pedal revolution, the bicycle rolls 10.5 meters.
Typical areas of development
Depending on the type of bicycle, the values differ significantly:
🚴 Racing bike: approx. 2.5 – 10 m (very high top speeds)
🚵 Mountain bike: approx. 1.5 – 7 m (hill-oriented)
🚲 Trekking / City: approx. 2 – 8 m (balanced)
⚡ E-bike: highly variable, often 1.5 – 9 m (depending on motor assistance)
Relationship with cadence
The development directly determines the speed at a specific cadence (pedaling frequency) :
👉 Speed = Development × Cadence
Example:
Development: 6 m
Cadence: 80 rpm
→ 6 × 80 = 480 m/min = 28.8 km/h
This makes it clear: 👉 It's not just the gear that counts, but also how fast you pedal.
Factors influencing the development
The development is influenced by:
Chainring size (front)
Rear sprocket size
Tire size (wheel circumference)
Gear type (chain, hub gear, automatic systems)
E-bike motor support (indirectly through riding feel and cadence range)
Development of e-bikes
With e-bikes, the development plays a special role because:
Engines often operate within an optimal cadence range
Excessive power output can cause the engine to "disengage".
Insufficient development results in unnecessarily high cadence.
Modern systems are therefore designed to ensure that drivers remain within the ideal support range as efficiently as possible.
Conclusion
Gear ratio is one of the most important, yet often underestimated, factors in cycling. It connects technology and riding feel and explains why two bicycles with similar gears can ride completely differently.
👉 Whoever understands development truly understands translation.
