Tank wheel for use with tracks

thingiverse

This larger wheel interfaces with a wide tank track and has most of the axle as part of the model. The axle size fits onto a roller blade bearing, which is made to accommodate it perfectly. A small hole at the tip of the axle needs to be drilled out to fit whatever drive mechanism you're using. In my case, I used a Tamiya gearbox from ebay and drilled the center out to about 3.1mm to press it onto the gearbox shafts. The arduino drives a H bridge shield and 5v is more than enough power for the motors, which will run quite a while on 4 AA batteries. My tank's frame isn't printed, but can easily be cut out of wood. The front wheels are also made with this model. I simply cut off the thin part of the axle and drilled out the center of the wheel to about 5.2mm and used a bolt to hold it in place. When assembling the gearbox, make sure to use the 207:1 ratio instead of the 58:1. It will be fast enough with this larger ratio and have plenty of torque to climb over things. I added STL files for the body and side of the tank that I show in the picture. The side of the tank needs to be mirrored in the slicer to produce the opposite side. The bearing size is 8mm (inner) x 7mm (thick) x 22mm (outer). It's held in place by three 3mm x 10mm screws.