Hex wheel hubs for 3mm and 4mm D shafts

thingiverse

I use these hex wheel hubs in my 150g and 1.36kg/3lb combat robots on N20 gearmotors with 3mm D shafts and GA25 gearmotors with 4mm D shafts. I then cut foam from kids' playmats, flip-flops, and similar materials or rubber wheels of the required size and cut the hex hole with a knife. Both types are designed to be tapped for M3 grub screws on the sides to keep them in place on the shaft and for M4 bolts at the ends to secure the wheels onto the hubs - an STL file for a washer is also included. These wheels are adjustable, lightweight, affordable, and hold up incredibly well in combat.