Large Rubber Track drive kit. All you need to drive the larger rubber tracks that have been around a while. There is information on how to use the smaller ones HERE and the principle is similar. The kit is supplied with four yellow plastic gears that will mesh with the teeth inside the hub. As you will discover from reading the article, linked to above, by simply leaving the gear out the drive hub it will become an idler, and combining this on a single chassis will allow the unit to be steered. The gears are a very firm fit in te hubs and are best removed using a rod pushed through the holes in the hub, first through one hole and then through the opposite hole.

I have also included four plastic tri-axle 57t gears that can be used instead of the yellow pinions if you want to use the tri-axle system instead. 

If you have any questions please contact me.