Gear Ratio, Development & Gear Inches
Gear Ratio = Chainring ÷ Cog. 52/11 = 4.73 (hard); 34/28 = 1.21 (easy). Development = distance per crank revolution. 100 gear inches ≈ moderate road gear.
Why This Stat Matters
Why: Gear ratios determine climbing and sprinting capability. Sheldon Brown's calculator is legendary. SRAM offers 10–52T cassettes for massive range. Compare drivetrains side-by-side.
How: Enter chainring and cog teeth. Gear Ratio = chain ÷ cog. Development = ratio × wheel circumference. Gear inches = ratio × wheel diameter. Gain ratio = development ÷ (2π × crank length).
- ●52/11 = 4.73 sprint gear; 34/28 = 1.21 climbing
- ●100 gear inches ≈ moderate road; 120+ high
- ●SRAM 10–52T enables steep climbing with 1×
Gear Ratio = Chainring ÷ Cog • Gear Inches = Ratio × Wheel Diameter
Development = Ratio × Wheel Circumference • Sheldon Brown • BikeCalc
Preset Drivetrains
Screenshot Summary
Gear range: 2.23 m (easiest) to 9.53 m (hardest). 328% total range. 0 overlapping ratios.
Gear Table
| Chain/Cog | Ratio | Dev (m) | Gear in | Gain |
|---|---|---|---|---|
| 50/11 | 4.55 | 9.53 | 123 | 8.79 |
| 50/13 | 3.85 | 8.06 | 104 | 7.44 |
| 50/15 | 3.33 | 6.99 | 90 | 6.45 |
| 34/11 | 3.09 | 6.48 | 83 | 5.98 |
| 50/17 | 2.94 | 6.16 | 79 | 5.69 |
| 50/19 | 2.63 | 5.52 | 71 | 5.09 |
| 34/13 | 2.62 | 5.48 | 71 | 5.06 |
| 50/21 | 2.38 | 4.99 | 64 | 4.60 |
| 34/15 | 2.27 | 4.75 | 61 | 4.38 |
| 50/24 | 2.08 | 4.37 | 56 | 4.03 |
| 34/17 | 2.00 | 4.19 | 54 | 3.87 |
| 34/19 | 1.79 | 3.75 | 48 | 3.46 |
| 50/28 | 1.79 | 3.74 | 48 | 3.45 |
| 34/21 | 1.62 | 3.39 | 44 | 3.13 |
| 50/32 | 1.56 | 3.28 | 42 | 3.02 |
| 34/24 | 1.42 | 2.97 | 38 | 2.74 |
| 34/28 | 1.21 | 2.55 | 33 | 2.35 |
| 34/32 | 1.06 | 2.23 | 29 | 2.05 |
For educational and informational purposes only. Verify with a qualified professional.
🏅 Sports Records
Gear Ratio = Chainring ÷ Cog. 52/11 = 4.73; 34/28 = 1.21
Gear inches invented in 1890s for penny-farthings. 100 ≈ moderate road
Development = distance in meters per crank revolution. 7 m = moderate
Gear Ratio = Chainring ÷ Cog. Gear Inches = Gear Ratio × Wheel Diameter (in). Development = Gear Ratio × Wheel Circumference (m). Sheldon Brown's calculator is the industry standard.
Key Takeaways
- Gear Ratio = Chainring teeth ÷ Cog teeth—bigger chainring or smaller cog = harder gear
- Gear inches invented in 1890s for penny-farthings; 100 ≈ moderate road gear
- SRAM 10–52T cassettes offer massive range for 1× drivetrains
- 53/11 is the highest common road gear; 12-speed is now standard
Did You Know?
How It Works
Step 1: Gear Ratio = Chainring ÷ Cog. 52÷11 = 4.73
Step 2: Gear Inches = Ratio × Wheel Diameter. 4.73 × 27 ≈ 128 gear inches
Step 3: Development = Ratio × Wheel Circumference. 4.73 × 2.096 ≈ 9.9 m/rev
Expert Tips
Drivetrain Comparison
| Setup | Lowest | Highest | Verdict |
|---|---|---|---|
| Road 2×11 | ~1.06 (34/32) | ~4.73 (52/11) | ✅ Balanced |
| MTB 1×12 | ~0.62 (32/52) | ~3.2 (32/10) | ✅ Wide range |
| Track fixed | = Highest | ~3.27 (49/15) | ⚠️ Single gear |
| Classic 3× | ~1.2 (30/25) | ~4.33 (52/12) | ❌ Overlap |
Infographic Stats
Official Sources
Disclaimer: Gear calculations assume standard wheel sizes and tire dimensions. Actual development varies with tire pressure and wear.