Tank Transmission, Belt Drive, 42:1 Reduction

This is a belt drive 42:1 reduction transmission that I have used, in pairs, in a couple of track vehicle projects. I drive them with 540 brushed crawler motors. These transmissions run very quietly.

Because there may be tiny variations in final print dimensions, I have included an alternate set of pulleys, (Plate #4) that will give the belts a little bit of slack if needed.

Please take note: (Edit 9/15/2024) I have used this transmission design successfully on a smaller tank, (10lb 8oz - 4.75kg) however, due to inconsistancies in the last batch of GT2 belts, I am getting slippage in one transmission of my larger tank, (13lb, 7oz - 6.1kg). I hope to be publishing a modification using GT3 belts in the near future.

Edit 9/15/2024: I have added a print profile for a revised set of pulleys using GT3, (3mm) belts. This modification eliminates the belt slip for heavier tank models. If you are using two transmissions, (left & right), you will need six belts, 204-3M (204mm circumference). The initial belt connection from the motor remains unchanged, using a GT2 belt of your choice. This is because the first belt in the series is high speed, low torque.