I have a setup where I have a step motor which I am attaching a gear onto. The motor will make the gear stand horizontal in a small vehicle. Is there any good gear combinations of LEGO gears that can transform the horizontal torque of the gear into vertical torque that drives the wheels of the small car I am building?

Are there multiple combinations of LEGO gears that can provide this kind of torque transmission?

  • 2
    you may want to omit the "gluing" part - it may have people flee in disgust and it's not really relevant to the question anyway
    – Joubarc
    Jun 29, 2013 at 8:33
  • @Joubarc Thanks for the comment, i am doing it since regular stepper motors powered by an arduino needs to have a "starting" lego brick attached to their rod that spins
    – bogen
    Jun 29, 2013 at 8:35
  • That said, this question is very similar, if not a full duplicate, of Strongest gear configuration
    – Joubarc
    Jun 29, 2013 at 8:43

2 Answers 2


There are a number of ways to do this. This is one of the easiest and earliest methods:

gear box

For that design, you'll need this part (3650):

crown gear

You can also do something similar using a combination of bevel gears or double bevel gears:

bevel gear double bevel gear


I'd like to cover two other techniques that work well, they both transmit horizontal torque to vertical but in slightly different ways that I believe may be useful for different situations.

Worm Gears

Worm Gear Illustration

Worm gears are fairly small (less than two studs long). Worm gears are designed to be operated in one direction and can only be driven by the axle with the worm gear. You can get some very high gear ratios when combining a worm gear with another gear.

Knob Wheel

Knob Wheel Illustration

Knob wheels are only compatible with other knob wheels, they cannot be used with gears. They can be used parallel (like standard gears) and at 90 degree angles (like crown/bevel gears).

I find knob gears are easier and more comfortable to turn by hand and they appear to be more commonly included with recent Technic sets.

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