TOOLS

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!

Lego Technic smoothly switching 2 speed automatic gearbox - with instructions

28 Aug 2020

This video presents a smoothly switching 2 speed automatic gearbox made out of Lego Technic. The gearbox uses the "differential jam" phenomena to prevent reverse torque transmission during the gear switch over point, when the driving gearing can be momentarily disengaged.

The gearbox automatically switches down by a ratio of 2/3 when the load on the output is sufficiently high by using a differential to detect the loading and to drive an orange rotary catch (first introduced in the Lego Technic Bugatti 42083). This is a smooth transition due to the reverse path being only one directional.

More to explore

Lego Technic Gearbox Theory Applied - how to apply theory to help design 2 speed automatic gearboxes

10 Nov 2020

This video applies lego technic gearbox, torque, and gearing ratio theory to design a prototype lego 2 speed automatic gearbox. First I describe the main components of an automatic gearbox, namely a gearing ratio selector and a torque detector. The ideal gear switch over torque point is described...read more

Lego Technic torque in practice - how to work with torque in automatic gearbox design

29 Oct 2020

n this video I present a ten level Lego Technic torque creation gadget for testing lego power function motors and automatic gear switching mechanisms. The effect of torque on a large lego PF motor is tested against the theoretical power curve to compare the optimal gear switching point in practic...read more

Lego 2 speed automatic car. Part 1

3 Oct 2020

This video explores the use of the lego technic "smoothly switching 2 speed automatic gearbox" inside of a test car to see how well it works to climb up a ramp.

The gearing ratio of the 2nd gear of the 2 speed automatic gearbox can be set using a manual 4 speed gearbox to choose...read more

Lego Technic 2 Speed Automatic Gearbox - Compact! With build Instructions.

15 Aug 2020

Here I present a design for a compact lego technic 2 speed automatic  gearbox. Instead of using a differential to react to torque on the output it uses the force on the gear teeth to push a liftarm to automatically change the gearing ratio to the 2nd speed once the torque threshold has been ...read more

Lego Technic 2 Speed Automatic Gearbox with Booster Motor

23 Dec 2020

A lego technic 2 speed automatic gearbox is presented. The point of difference of this automatic 2 speed gearbox is a secondary booster motor is activated once the torque detector senses a large enough torque on the output of the automatic gearbox.

The second motor is turned on by a pole ...read more

Lego Technic 2 Speed Auto Gearbox - a new hope - with build instructions

28 Nov 2020

This Lego technic 2 speed automatic gearbox design uses a worm gear for torque detection and gear switching combined. Previous Lego 2 speed automatic gearboxes have used a Lego differential for torque detection to drive an orange rotary catch to switch gears using a switch component.

Lego Technic Applied Gearbox Theory Improved

20 Nov 2020

This Lego Technic video demonstrates an improved design of a Lego technic 2 speed automatic gearbox based on a theoretical approach. Typically a Lego automatic gearbox consists of two stages namely a gear selector and a torque detector. In this video, both of these components are improved upon.read more

Lego Technic Optimal Gear Switching Ratios

17 Oct 2020

This video presents the relationship between lego technic motor torque and speed and shows there is an peak power for each electric motor.

The peak power is calculated and a formula presented relating the power operating point as a percentage of peak power. From this an operational power ...read more

Lego 2 Speed Automatic gearbox - worm gear prototype. Includes build instructions.

26 Sep 2020

This video present a lego technic 2 speed automatic gearbox based on using a worm gear for torque detection.  The 2 speed transmission gearbox works by using the linear counteraction force on the worm gear to connect a gear to create a second speed.