The Brick Experiment Channel has taken a break from destroying every LEGO brick known to man. Today, it will indulge us with a simple LEGO gear train:

YouTube video

The goal: to create the longest 1:1 LEGO gear train imaginable. The restrictions: they can only use LEGO parts to create the gear train. On top of this, both the first gear and the last gear must rotate at the same speed – even if it slows down to a very sad crawl.

LEGO gear train

The first 30 or so gears can be easily placed onto a LEGO beam, with the first gear being connected to an electric motor. Once it starts to get a little crowded, you will see some of the gears shift out of their holes. LEGO bushes (pieces of cylindrical plastic that cover the axles) can easily remedy this problem and keep the axles from popping out. And so the gear stacking madness continues…

LEGO gear train

When you start hitting the 50-gear mark, you’ll find that increasing the motor’s rotations per second will start to put on more strain than the connectors can handle – you’ll even see some of the LEGO gears fly out of the beams! To keep the gears from popping out the top side, you can add axles on the top of the gears, fit them with bushes, and add a whole new beam on top of the rows and columns to make the whole thing sturdier.

LEGO gear train

By utilizing this top beam method, you can get away with adding more and more gears while gradually increasing your motor’s RPM when the gears slow down. The Brick Experiment Channel has to swap out the motor’s batteries as the gear count reaches 93 gears, which allows them to continue stacking gears for another extra row.

All throughout the video, you might have heard a faint buzzing noise. That’s the motor struggling to keep the gear chain running. What started out as a low hum is now a very audible cry for help from the motor for the experiment to stop.

LEGO gear train

The Brick Channel eventually stops at the 111-gear mark, as they can’t add any more gears without making adjustments using non-LEGO items. If you want to make this gear train even longer, you could oil the gears and stack another hundred or more of these babies. Here’s to hoping they might actually do this in a future video!


Carlos wrestles gators, and by gators, we mean words. He also loves good design, good books, and good coffee.