In this article, you will learn everything you need to know about gear ratios in bicycle gears – clearly explained and with practical tips for selection and use.
What is the gear ratio on a bicycle?
The gear ratio describes the relationship between the front chainring and the rear sprocket. It determines how often the rear wheel rotates when you pedal once. This is crucial for your effort and speed.
Formula:
Gear ratio = number of teeth front / number of teeth rear
Example:
Front chainring with 50 teeth, rear sprocket with 25 teeth → 50 / 25 = 2.0
This means that one rotation of the crank results in two rotations of the rear wheel.
Small vs. large translation – what’s the difference?
Why is the correct translation so important?
The right gear ratio determines your ride comfort, efficiency, and performance. Here are a few examples:
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On the mountain you need a small gear ratio so that you can pedal smoothly despite the incline without overexerting yourself.
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On straight stretches or downhills, a large gear ratio is useful to increase speed.
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When riding with luggage or a child seat, lighter gears are helpful to better manage the additional load.
Gear ratio and development: What is the difference?
While the gear ratio is the ratio between two gears, the gear ratio describes how far you actually travel with one crank revolution. This depends on the gear ratio and the tire circumference.
Example:
A wheel with a 2.1 m tire circumference and a gear ratio of 2.0 → development: 4.2 m per crank revolution.
Gear ratio tables help you calculate the right gears for specific situations – e.g., for track racing, fixies, or bike fitting.
How many gears do you really need?
Modern bicycles often have between 9 and 12 rear sprockets and one or two front chainrings. The more gears, the more finely you can adjust the gear ratio. However, more gears don't automatically mean better riding.
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Single-speed gears (e.g. 1x12 on MTBs) are lighter, easier to use and ideal for off-road use
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2-speed or 3-speed gears offer more bandwidth, especially when traveling or in the mountains
Tip: If you often ride on flat terrain, a smaller gear range is often sufficient. If you ride uphill or carry a lot of luggage, a wider gear range is helpful.
Which gear ratio suits which type of bike?
| Bicycle type |
Typical translation |
Goal |
| racing bike
|
50/34 front, 11–30 rear (e.g. compact), 11 or 12 cassette
|
High speed, efficiency |
| Gravel bike
|
46/30 or 1-speed with 11-42 cassette |
Versatility, terrain |
| Mountain bike (MTB)
|
1-speed, e.g. 32 front, 10–51 rear |
Steep climbs, trails |
| City/trekking bike
|
2- or 3-speed, often 11–34 rear |
Everyday life, tours, comfort |
| E-bike
|
Often hub gear or 1-speed derailleur with motor support |
Energy-saving driving |
Conclusion: The right translation makes the difference
Whether you're riding sportily, commuting to work, or going on a bikepacking tour, the right gear ratio will help you ride efficiently, comfortably, and in control. It's worth not underestimating this issue. If you know your cadence and terrain, you can select gears specifically or even adjust your cassette or chainrings.
Tip at the end:
Consciously test different gear ratios! For example, try riding with one gear lower or one gear higher and observe how your riding style, your workload, and your enjoyment change.
