Vex Pro Mecanum Wheel Tetrix Adapter / Thunderhex to Tetrix Adapter
As opposed to other designs, our approach was to make the size of the thunderhex axle fit the diameter of tetrix standards. The hole size is the same as any hole you would see in the center of a tetrix channel, meaning that it can fit on both motors and smaller tetrix axles with bushing or axle hubs.
You will need some way to secure the wheel on the other end or else it could slip off. I would just put some bushing in and put a tetrix axle through it a little with an axle hub on the other size just to secure it in place.
Made by FTC Team 6567 RoboRaiders
WARNING: there are 2 different kinds of VEX mecanum wheels. THESE are the wheels which this part was designed for:
http://www.vexrobotics.com/mecanum-wheels.html
DO NOT attempt to use this part with http://www.vexrobotics.com/276-1447.html, as the axle is different.