Aftermarket rubber tracks are available for Komatsu D20 and Komatsu D21 bulldozers.
Komatsu D20 rubber tracks and Komatsu D21 rubber tracks are very heavy and it is important to get a genuine bulldozer track, not a lighter duty product. A picture of a 12" Komatsu D21A rubber track is as follows:
The Komatsu D20P and D21P have a wider track which is 20" wide. These machines you get much lower ground pressure but aren't able to fit in a lot of spots that the D20A and D21A will. For the Komatsu D20P and D21P rubber tracks, you can also downgrade to a 16" option that will make the machine narrower and also greatly reduce the cost of the rubber track.