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Electric Scooter Repair Help > Modification and Custom Project Help > Top Speed and Gear Ratio Calculator


Top Speed and Gear Ratio Calculator

Calculator     Gear Ratio Guide


Top Speed and Gear Ratio Calculator

* Enter Parameters Below

* Motor Speed

RPM (example: 2500)

* Motor Sprocket

Teeth (example: 11)

* Wheel or Axle Sprocket

Teeth (example: 65)

* Tire Height (Diameter)

Inches (example: 12.5)

Speed and Gear Ratio Calculation Results
Top Speed: MPH
Gear Ratio: :1


75% Speed

Gear Ratio Calculator for Vehicle with Jackshaft

This calculator determines the top speed of the vehicle with no margin for mechanical, rolling, or wind resistance. These resistance factors could make the top speed slower than the calculation. The amount that the top speed will be reduced by resistance depends on many factors such as the power of the motor, weight of the vehicle and rider, size and air pressure of the tires, incline degree that the vehicle is going up, and headwind. The top speed could also be increased above the top speed calculation by riding down hill, or riding with a strong wind against your back.

When riding on flat ground the top speed is usually only reduced by a small amount.


Gear Ratio Guide

This guide is for modifying, designing and building custom electric; scooters, bikes, go karts, ATVs, wagons and other similar light electric vehicles.

Motor Types

There are two types of electric motors; standard motors and gear motors. Standard motors have shafts directly attached to the motor windings with shaft output speeds commonly between 1800-3000 RPM. Gear motors have gear reduction transmissions built into them with shaft output speeds commonly between 400-550 RPM.

Standard Motors (Electric Scooter Motors)

Standard motors are made for electric scooters, go karts, and other similar vehicles with 6"-12" wheels. Standard motors should not be used for electric bicycle projects unless a gear reduction transmission such as a jack-shaft is used with them to lower the gear ration so they can operate near their top RPM while the vehicle is in motion, otherwise they will run at too low of an RPM which will cause them to overheat and possibly burn out along with not allowing them to produce the full amount of power that they have the potential to.

Gear Motors (Electric Bicycle Motors)

Gear motors are made for electric bicycles with 16" through 26" wheels. Gear motors can also be used on vehicles with smaller wheels if a slow top speed and a high amount of torque for uphill climbing or driving through sand or mud is required.

Motor to Wheel Gear Ratio and Motor Type Examples


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