Can you give me some advice how to make it so motor will be in the middle, but at the same time keep the functionality of the 2 axles on the sides? It can go further up if necessary.

motor configuration

  • Can you confirm two conditions please: 1) should each axle rotate in different directions? 2) should axles spin at the same speed?
    – Alex
    Mar 3, 2022 at 14:47
  • Yes, that's corrrect
    – Neikar
    Mar 3, 2022 at 14:51
  • 3
    Just an observation. I hope you've used blue pin to attach gear just as a placeholder in your picture. This won't work well with real bricks, even with frictionless pin. It is better to use an axle instead, braced with liftarm/beams from both sides.
    – Alex
    Mar 3, 2022 at 15:15

2 Answers 2


Something like this would work. Since this is just an idea pictured assembly doesn't feature any bracing required for this solution to work properly. Another thing to mention - 8T gears doesn't like high load (both torque and rotational speed), so keep that in mind as well. Axle in the middle has been added just to show it is connecting 8T gear with 16T below.

Assembly with 8T gears

To minimize wear on the 8T gears, consider replacing the with 24T gears (if they fit inside your model), like so:

Assembly with 24T gears


I'd address this with bevel gears:

enter image description here

  • Interesting. What are the advantages/disadvantages to bevel gears over a solution closer to OPs original design (such as Alex’s solution)?
    – DukeSilver
    Mar 4, 2022 at 21:47
  • 5
    More symmetric solution, avoidance of the 8 tooth gears (which Alex also indicated don't bear load/speed well), less backlash (or at least the backlash distributed symmetrically over the resulting axles). Not knowing OP's further design intentions my solution might of might not fit better, but at least OP now has an alternative option. Mar 4, 2022 at 22:15
  • 6
    It also has an advantage of being already well braced. And for some reason I have a suspicion it may even have less friction.
    – Alex
    Mar 5, 2022 at 7:57
  • If size is an issue, you could use a 7L beam if you removed the outer two black frames, and replace outer two tan bevel gears with double bevels. Mar 9, 2022 at 3:31
  • @Matthew, not sure what you mean, but I would imagine such solution has poorly braced gears Mar 9, 2022 at 4:36

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