# What is a gearing ratio?

A gearing ratio measures the ratio of the output speed to the input speed of a geared system. So if the output axle makes 1 rotation per second and the input axle makes 3 rotations per second then the gearing ratio is 1 to 3 or 1/3 which is also written as 1:3. Given a pair of gears you can calculate the gearing ratio as simply the number of teeth on the driving gear divided by the number of teeth on the gear being driven. For example below is an image of an 8 tooth lego gear driving a 24 tooth gear. The gearing ratio is 1/3 as the input axle (red) will rotate 3 times for each rotation of the output axle (yellow).

# More to explore

## New Flat 12/20 Gear Friction

The Lego Technic set 42140 App-Controlled Transformation Vehicle introduces two new gears - a flat version of the 12 tooth bevel gear and a flat version of the 20 tooth bevel gear. These gears are designed to have less friction.

In this video I measure the difference in gearing efficiency...read more

### Gearing Ratio Calculator Tool Help

## Measuring Gearbox Efficiency

This video describes a method for measuring the efficiency of a gearbox using the Lego Technic Powered Up hub. Gearbox efficiency is defined as the ratio of the output power to the input power and here I show how to measure each of these values to allow you to calculate the overall efficiency.read more

### How do you make a 1:N gearing ratio?

## Lego Technic Gearing Ratio Tool Update

This video presents updates to the Technic Brick Power Lego Technic Gearing Ratio Calculator tool specifically on underconstrained differential systems. These are systems in which the differentials are not fully constrained and therefore have 1 or more degrees of freedom within them.

The ...read more

## Lego Technic Gearing Ratio Calculator Tool

Here I present my new Lego Technic Gearing Ratio Calculator tool. This tool allows you to upload your Lego Technic .ldr (Lego Draw) file and it will simulate the gearing system and visualize it as well as showing the gearing ratios relative to the input component.

The tool can be accessed...read more