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Gear Ratio Calculator

Gear ratio defines how many full revolutions the rear wheel turns for a single complete 360-degree pedal turn.

Formula & Mechanics
Gear Ratio = Chainring Teeth / Rear Cog Teeth

Powered by our unified DrivetrainCalculationEngine. All metrics remain in sync.

Close-up of bicycle rear cassette and derailleur gears
Chainring Teeth divided by Cassette Cog Teeth

1. Drivetrain Setup

Chainrings & Cassette

2. Wheel & Tire Model

Dimensions & Rollout

Calculated wheel dimensions are theoretical estimates. Actual rollout varies with tire pressure, rim inner width, and rider weight. Use measured rollout for highest accuracy.

Gear Matrix

Chainrings (rows) vs Sprockets (columns). Color scale indicates range from lowest to highest.

Chainring \ Rear Cog11T12T13T14T15T17T19T21T24T28T32T34T
50T121.3"111.2"102.7"95.3"89.0"78.5"70.2"63.6"55.6"47.7"41.7"39.3"
34T82.5"75.6"69.8"64.8"60.5"53.4"47.8"43.2"37.8"32.4"28.4"26.7"
Range scale:Lowest→Mid→Highest
Orange dot = Duplicate or Near-duplicate gear ratio

Gear Table

Comprehensive sorted breakdown for every chainring x cassette sprocket combination

24 Total Gear Combinations
GearCombination
Ratio
Gear Inches
Development
Gain Ratio
Jump %
Speed (@90rpm)
Status
134T × 34T1.00 : 126.7"2.14 m1.97-11.5 km/h (7.2 mph)Unique
234T × 32T1.06 : 128.4"2.27 m2.09+6.3%12.3 km/h (7.6 mph)Unique
334T × 28T1.21 : 132.4"2.59 m2.39+14.3%14.0 km/h (8.7 mph)Unique
434T × 24T1.42 : 137.8"3.03 m2.78+16.7%16.3 km/h (10.2 mph)Unique
550T × 34T1.47 : 139.3"3.14 m2.89+3.8%17.0 km/h (10.5 mph)Unique
650T × 32T1.56 : 141.7"3.34 m3.07+6.3%18.0 km/h (11.2 mph)Unique
734T × 21T1.62 : 143.2"3.46 m3.18+3.6%18.7 km/h (11.6 mph)Unique
850T × 28T1.79 : 147.7"3.81 m3.51+10.3%20.6 km/h (12.8 mph)Near (1%)
934T × 19T1.79 : 147.8"3.82 m3.52+0.2%20.6 km/h (12.8 mph)Near (1%)
1034T × 17T2.00 : 153.4"4.27 m3.93+11.8%23.1 km/h (14.3 mph)Unique
1150T × 24T2.08 : 155.6"4.45 m4.09+4.2%24.0 km/h (14.9 mph)Unique
1234T × 15T2.27 : 160.5"4.84 m4.45+8.8%26.1 km/h (16.2 mph)Unique
1350T × 21T2.38 : 163.6"5.09 m4.68+5.0%27.5 km/h (17.1 mph)Near (2%)
1434T × 14T2.43 : 164.8"5.19 m4.77+2.0%28.0 km/h (17.4 mph)Near (2%)
1534T × 13T2.62 : 169.8"5.59 m5.14+7.7%30.2 km/h (18.7 mph)Near (1%)
1650T × 19T2.63 : 170.2"5.62 m5.17+0.6%30.4 km/h (18.9 mph)Near (1%)
1734T × 12T2.83 : 175.6"6.05 m5.57+7.7%32.7 km/h (20.3 mph)Unique
1850T × 17T2.94 : 178.5"6.28 m5.78+3.8%33.9 km/h (21.1 mph)Unique
1934T × 11T3.09 : 182.5"6.60 m6.07+5.1%35.7 km/h (22.2 mph)Unique
2050T × 15T3.33 : 189.0"7.12 m6.55+7.8%38.4 km/h (23.9 mph)Unique
2150T × 14T3.57 : 195.3"7.63 m7.02+7.1%41.2 km/h (25.6 mph)Unique
2250T × 13T3.85 : 1102.7"8.22 m7.56+7.7%44.4 km/h (27.6 mph)Unique
2350T × 12T4.17 : 1111.2"8.90 m8.19+8.3%48.1 km/h (29.9 mph)Unique
2450T × 11T4.55 : 1121.3"9.71 m8.93+9.1%52.4 km/h (32.6 mph)Unique