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settings Gearing Calculator

Current
T
T
:1
mm
New
T
T
:1
mm
Current
New
Spur:Pinion Ratio
{{ currentGearRatio }}
{{ newGearRatio }}
Final Drive Ratio
{{ currentFDR }}
{{ newFDR }}
Rollout
{{ currentRollout }}mm
{{ newRollout }}mm
{{ changePercentFormatted }}
→ {{ changeDescription }}

Gearing Calculator Help

Inputs

Pinion: Number of teeth on the pinion gear (motor gear)

Spur: Number of teeth on the spur gear (transmission gear)

Internal Ratio: Transmission internal ratio multiplier (default: 1.0 for direct drive)

Tire Diameter: Diameter of your tires in millimeters (optional, needed for rollout calculation)

Calculations

Spur:Pinion Ratio: Spur ÷ Pinion - Shows gear reduction

Final Drive Ratio (FDR): Gear Ratio × Internal Ratio - Total drivetrain reduction

Rollout: (Tire Diameter × π) ÷ FDR - Distance traveled per motor rotation (in mm)

Change: ((New FDR - Current FDR) × 100) ÷ Current FDR - Percentage change in gearing

Understanding Change

Positive % (Red): More load on motor, better acceleration, lower top speed

Negative % (Green): Less load on motor, higher top speed, reduced acceleration