Gearing Ratio Calculator

Check out the Beta version my Lego Technic Gearing Ratio Calculator Tool:

This tool allows you to upload your Lego Technic project .ldr file and analyse the gearing ratios between any two connected gears or axles. Currently supports most gears, axles, worm gears, some differentials, cv joints and universal joints. See the video tutorial on how to use it. It is a work in progress and I would love to hear your feedback on it. Click here to try it out.

Note: As of 25 Septemeber 2021 the tool supports CV joints, linear speed via the radius of the component and improves on the frame rate for higher numbers of parts in a model).

Technic Elbow Art

This is a tool to create "Lego Technic Elbow Art" - a series of intertwined elbow pieces as a single sequence. Choose your dimensions and search parameters and search for new dense solutions and set a record! 

Download your Elbow Art as an .ldr file and build it yourself. Click here to try it out!

What is a gear train?

17 Aug 2021

A gear train is a sequence of gears and axles mechanically connecting an input axle to an output axle. This can be any number of axles and therefore creates a "train" of gears. Usually each intermediary axle has two gears on it - one being driven by the previous axle's gear and one that drives the next axle in the series. The diagram below shows and example of a gear train. On the left is the input axle and this drives the black 12 tooth gear onto the tan 20 tooth gear which is connected to the 2nd axle. This axle then drives the grey 16 tooth gear onto the next 16 tooth gear (on the third axles) and that axle in turn has an 8 tooth gear driving the 24 tooth gear on the output axle (on the right). The overall gearing ratio between the input axle on the left and the output axle on the right is simply the product of all of the individual gearing ratios in the gear train. So that gives:

Overall Gearing Ratio =  (12 / 20) x (16 / 16) x (8 / 24) = 1 / 5 or 0.2.

This means the output axle rotates one revolution for every 5 revolutions of the input axle, or simply that the output axle is 1/5 the speed of the input axle.

More to explore

Lego Technic Gearing Ratio Tool Update

4 Sep 2021
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 more

New Flat 12/20 Gear Friction

23 Apr 2022
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 more

Measuring Gearbox Efficiency

6 Nov 2021
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 more