DRIVETRAIN / TOOL 03

Gear ratio.

Count the teeth on the motor and wheel pulleys to understand your belt-drive gearing.

BELT DRIVE

Count the teeth

Enter the number stamped on each pulley, or count its teeth once around.

Motor pulley small pulley

Wheel pulley large pulley

Each tooth in the diagram represents one tooth entered above. The wheel pulley shown here is an illustration.

Electric skateboard drivetrain with the small metal motor pulley exposed near the belt guard — **Motor pulley teeth ↗** Count the ridges all the way around this small gear. For the wheel pulley, count the teeth on the larger gear attached to the wheel.

THE RESULT

Your ratio

GEAR REDUCTION

2.40: 1

The motor turns 2.40 times for one wheel rotation.

Motor pulley15T

Wheel pulley36T

Ratio = wheel pulley teeth ÷ motor pulley teeth. More reduction generally gives more wheel torque and less wheel RPM at a fixed motor speed. Changing pulleys can also require another belt length.

On a hub or direct-drive board without external pulleys, this calculator does not apply.

RESEARCH / FURTHER READING

Sources

01Evolve GTR remote manualIllustrates production board wheel and gear settings, including standard gear sizes.02Gates drive design worksheetIndustrial belt-drive reference for pulley speed ratios and drive sizing.

Calculations describe ideal geometry. Actual ride speed and remote behavior depend on the board and its firmware.