Specifically designed to provide the maximum reliability and performance, drive sprockets especially should be replaced at the same time as new rubber tracks are fitted.
Idlers tension the rubber track and guide it around the front of the track undercarriage. If worn they can cause a track to continually come off the frame, potentially leading to serious damage.
Top (carrier) Rollers
Often not fitted to the smallest mini excavators, top rollers serve the purpose of guiding the rubber track over the undercarriage frame. They also need to be replaced once worn.
Bottom (track) Rollers
Designed, engineered and manufactured for applications requiring high load resistance, track rollers carry the brunt of an excavator's weight. They should ideally be changed as a complete set rather than individually, in order to ensure that the machine's weight remains evenly distributed.