Cycling Gear Ratio Calculator
Calculate your gear development, speed at any cadence, and compare chainring/cassette combinations to find the optimal gearing for any terrain.
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The formula
Gear Ratio = Chainring Teeth / Sprocket Teeth
Full derivation and the conditions it holds under are in Method and basis, below.
Method and basis
How the figure above is derived, and when not to act on it.
How Gear Ratios Work
A gear ratio is the mechanical advantage between your chainring (front) and sprocket (rear):
Gear Ratio = Chainring Teeth / Sprocket Teeth
A 50/17 combination gives a ratio of 2.94 — for every full pedal revolution, the rear wheel turns 2.94 times.
📏 Gear Development (Metres per Pedal Stroke)
Gear development tells you exactly how far you travel with one complete pedal revolution:
Development (m) = (Chainring / Sprocket) × Wheel Circumference (m)
Wheel circumference reference:
| Tyre Size | Circumference |
|---|---|
| 700c × 23mm | 2.096 m |
| 700c × 25mm | 2.105 m |
| 700c × 28mm | 2.136 m |
| 700c × 32mm | 2.155 m |
| 650b × 47mm | 2.149 m |
⚡ Speed at Any Cadence
Speed (km/h) = Development (m) × Cadence (rpm) × 60 / 1000
Example: 50/17, 700×25c, 90 rpm:
- Development = (50/17) × 2.105 = 6.19 m/rev
- Speed = 6.19 × 90 × 60 / 1000 = 33.4 km/h
🏔️ Gearing Strategy by Terrain
Road Racing — Standard Setup
| Terrain | Recommended Gearing | Why |
|---|---|---|
| Flat sprinting | 53×11 | Maximum speed at 100+ rpm |
| Rolling hills | 50×17–21 | Tempo riding, ~30–35 km/h |
| HC climbs (8%+) | 34×28–32 | Sustainable cadence at low speed |
| Steep mountains | 34×34 (compact + 11-34 cassette) | Keeps cadence above 70 rpm |
Gravel / Adventure
- Minimum rear gear: 11-42T or 11-46T cassette with 1× drivetrain
- Recommended front: 38–42T single ring for mixed terrain
🔄 Cadence Science
Optimal cadence varies by rider type: * Road racing: 80–100 rpm (higher cadence reduces muscular stress, increases cardiovascular load) * Time trials: 90–100 rpm (aerodynamic position limits hip mobility at very high cadence) * Climbing: 70–85 rpm (torque efficiency improves at lower cadence on steep grades) * Track/sprint: 110–130+ rpm at peak power output
The 70 rpm Rule: Below 70 rpm, neuromuscular efficiency drops sharply and knee stress increases. If you're grinding below this, you need an easier gear.
📊 Common Road Bike Gear Combinations
| Setup | Lowest Gear | Highest Gear | Use Case |
|---|---|---|---|
| Compact (50/34 + 11-32) | 34×32 | 50×11 | Sportive / gran fondo |
| Standard (53/39 + 11-28) | 39×28 | 53×11 | Road racing |
| Semi-compact (52/36 + 11-30) | 36×30 | 52×11 | All-round racing |
| 1× gravel (40T + 11-42) | 40×42 | 40×11 | Mixed terrain |
WinSport Editorial & Research Standards
All formulas and reference values used in this tool are sourced from peer-reviewed scientific literature and validated clinical guidelines. Our research team continuously audits each calculator for accuracy and updates methodology as new evidence emerges.
Read the Science
Sports Science Articles- Most Amateur Cyclists Are Riding in the Wrong Gear — Here's the Physics Behind WhyGear selection is one of the most undercoached skills in cycling. Most amateurs spin too low or grind too high — and neither produces optimal power output.4 min read
- You're Riding the Wrong Chainring — Why Most Sportive Cyclists Should Drop to CompactStandard 53/39 gearing is designed for racing professionals. Most sportive and gran fondo riders should ride compact 50/34 or sub-compact 48/32 — here is the gear ratio mathematics.5 min read
- Every Road Bike Ships With the Wrong Crank Length for Most Riders170–175mm cranks are industry default, but femur length determines optimal crank arm length. Here's the biomechanics evidence for personalised cycling fit.5 min read
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