Off-road wheel for balancing robot

I have 3D printed the self-balancing robot frame from:

https://www.instructables.com/id/Brushless-Gimbal-Balancing-Robot/

I then bought two marSpower 2208 gimbal motors.

I decided I wanted rock crawler wheels, so I needed a wheel with a flat(ish) hub with 3 or 6 spokes, as the gimbal motor has 3 screws on every second of 6 spokes.

beast_c_a_t came to the rescue with a 3 spoke hub, though it had a protrusion that cupped a hex nut. It need some work to modify it.