Pololu 30T Track Set – Red
This set contains components for adding a tracked drive system to a small robot or vehicle. It consists of:
- Two silicone tracks
- Two ABS drive sprockets
- Two ABS idler sprockets
- Two M3 shoulder bolts with a 5mm threaded portion
- Two M3 shoulder bolts with a 12mm threaded portion
- Two washers and M3 nuts
A pair of idler sprockets is also included in the set; these are very similar to the drive sprockets, with the main difference being that they are designed to spin freely instead of attaching to a motor shaft. They can be mounted with the provided shoulder bolts as shown in the diagram below. (The blue component labeled “ROBOT CHASSIS” represents a bracket or piece of a robot chassis that the sprocket is being mounted to, and is not a part included in the set.)
|Exploded view diagram showing an idler sprocket and its mounting hardware.|
This track set comes with red sprockets and 30T tracks.
|Pololu 30T Track Set – Rlack.|
A dimension diagram containing the sprockets, tracks, and bolts is available here (618k pdf). Several key dimensions are highlighted below:
- Sprocket diameter: 35 mm (1.38″)
- Diameter with track: approx. 39 mm (1.54″)
- Track width: 14.6 mm (0.57″)
The threaded portion of the shoulder bolts can be cut to the desired length.
The ideal spacing between the centers of the two sprockets is about 48 mm for the 22T tracks and 85 mm for the 30T tracks. Because the tracks are elastic, they will maintain tension even if you do not precisely match this distance. However, if the spacing is too short, they will be loose and more likely to slip off; if the spacing is too long, additional strain will be placed on the sprocket shafts, and the motor might not be able to turn as well.
|Sprocket spacing diagram for the Pololu 22Tand 30T track sets.|