So, I am building a tank model and this is the transmission I have been working on:

upper view

side view

Description: There are two gear pairs for gearing up (16t to 8t gears) and one gear pair for gearing down (worm gear to 8t gear hidden beneath it) for each of the two M motors. The final gear ratio is 1:2 resulting in half the speed and twice (roughly) the torque of the M motors. The grey 24t gears are the ones who transfer motion to the tracks.

Questions: I would like to know if there is a better way to transfer the power of the two M motors to the 8t gears which are located beneath the worm gears. The problem I have is that the worm gears I use require a lot of gearing up to rotate fast enough (even what I achieved above is not enough). The additional gears result in lost energy and more points that could potentially break. Specifically I want to know if it is possible to achieve similar gear ratios with less gear pairs? Also are there any tips that would help me reduce the size of the above configuration? Is there an entirely different configuration other than the above which would lead to better results (gear ratio preferably less than 1:2, tougher)? Should I prefer bevel over normal gears? Is it worth it upgrading to two L motors? And lastly do you have any general tips regarding transmission and tank building?

  • 1
    "Is it worth it upgrading to two L motors?" The L motor is actually quite-a-bit better then the M motor. Unless the load is very low, I tend not to avoid the M motor. Sep 9, 2017 at 16:23

2 Answers 2


There are plenty of gears designed for 90 degree, search bricklink for "technic gear bevel" and "technic gear crown". There's also the "technic knob wheel", that seems to be used a lot outside technic, but I have a feeling that goes badly with a motor.

In my building the only application for worm gears is to gear things down, with regards to to size you can't beat the solutions it offers. But you're first gearing up to then gear down, that looks silly.

  • 2
    This is my first ever motorized build, I would appreciate if you did not suppose I am a pro. That is in regard of my configuration being silly. I know it is not good but I have been trying my best, I would not have come to this site otherwise.To the point now, I indeed tried the crown gears, but no matter what the axle would bend when pressure was applied to it even though it was secured from both ends. Also if you look closely at the pictures, the suspension of the rear most ground wheel will be blocked If I try to instal an axle vertical to the motors. Thanks anyways! Sep 9, 2017 at 15:25
  • 2
    Incidentally, the 4-knob gear is pretty good for 90deg rotation under heavy loads and does work with motors. It can take more load than the bevel gears without failing. Sep 9, 2017 at 16:21


Ok, I think I found a nice solution using only 3 gears per motor (instead of six). Now the moc can actually move and quite fast because of the 1:1,5 gear ratio. Thanks to everyone who helped!

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.