Summary These wheels were designed to work with the 3D printable rc cars I have posted in the past. The tires need to be printed with a flexible filament, the softer the better. I used m3 screws to hold everything together. The bearings, however, are skateboard bearings and they are held in by melting the tabs on the 3d pained hub to hold the bearing in, shown in the pictures. The rear motor hub is made to fit a dji phantom 1 motor, so this part may need to be changed to fit the motor being used. Happy Printing!