# How do you make a 1:2 gearing ratio?

To make a 1:2 gearing ratio you need to mesh two gears where one gear has double the number of teeth of the other. So possible combinations would be an 8 tooth gear driving a 16 tooth gear, or a 12 tooth gear driving a 24 tooth gear or a 20 tooth gear driving a 40 tooth gear (there is no 32 tooth gear, so 16 and 32 is not an option). The only pair of gears that can be meshed easily on a regular liftarm grid are 12 and 24. The other two combinations need an uneven spacing or an intermediate gear to work. So the simplest solution is shown below. The axles are set 1 across and two up apart (like a knight jump in chess).

Of course there are other solutions but the above is considered the simplest.

# More to explore

### Gearing Ratio Calculator Tool Help

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## 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

## 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

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## 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

### How do you make a 1:4 gearing ratio?

### What is a gearing ratio?

## 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

## How to mesh any two Lego gears on a regular grid!

In this video I analyze all of the eight regular lego technic gears and demonstrate how any two of them can be meshed on a lego grid.

A sum of radii chart is used to determine the possible diagonal meshing combinations. These are then combined with "intermediate" or "idler&...read more