29. November 2020

LEGO Technic axles and chassis

Features: axles, custom tires, diff-lock and chassis

An axle is the start for each LEGO technic car and truck. Here, you can find a collection of axles and chassis I developed for different models. Important: the specification of axle width relates always to the width between the tires.

13 studs axle with diff-lock and suspension

For an amphibious craft I need an axle which is able for off-roading with suspension and diff-lock. This was necessary so that the model paddles simultaneously with all tires in the water with diff-lock and can climb at the shore out of the water. The model was never finished but at least I made a video about the axle.

Custom tires at LEGO steering axles

Unfortunately, LEGO hasn’t produced a scale 80 mm tires until now (august 2020). The LEGO 81.6 mm balloon tires are not scale for the most models and can only be used with 3 studs steering knuckles. With longer steering knuckles (optimal: 4 studs long steering knuckles together with 7 oder 13 stud gear rack and 90° deflection of PF servo motor) the balloon tires touch the steering knuckles (it can work with Ackermann steering geometry). Therefore, it is easier to use custom tires if you want to use the 43.2 wheels. (It may work with bigger tires and wheels).

13 stud axles for chassis with rear and center diff-lock and custom tires

This chassis was built for optimal off-read performance. Therefore, the axles are suspended and the chassis has a center and rear axle diff-lock. The diff-lock is engaged via two small pneumatic cylinders at the rear axle and at the middle differential. The axles were built for realistic custom off-road tires. Generally, there are serious space issues at 13 stud axles with suspension, all-wheel drive, diff-lock and steering. Therefore, it was not possible to use original LEGO tires on the 43.2 mm wheels.

13 stud axles with independent suspension

A small chassis with 4 x 4-wheel drive and independent suspension. In this chassis the differentials are aligned with the drive shaft in the chassis. After the differentials the drive shaft is transferred via bevel gear to the suspension and wheels. Like this it is possible to make a 13 studs wide axle with differential and independent suspension.