The Hubs or Rims which holds either the tracks or tires of the wheels comes in many different shapes and sizes in this kit. There are a total of 6 different types of rims
Main Drive Sprocket (x2) attach with gearbox BO-2, Idler wheel (x2), Small Drive Sprocket (x2), Medium wheel (x6), Small Support Wheel (x10) and Poly cap (x12)
The angled shafts 100mm by 4mm diameter (x4).
The Tracks are meant to be placed together with the rims in this kit. They come in 3 different sizes and can be inter-locked together as well to firm a much larger track.