Operator engagement can help control the single largest expense of running a dozer — the undercarriage.
“Operators spend many hours in a machine daily and know what sounds normal,” says Bruce Boebel, senior product manager, tracked products, Komatsu America. “Operators need to listen to their undercarriage. Early detection of problems can reduce wear and save potential ‘victim’ components.” For example, a roller that stops rotating due to a “material packed” undercarriage can start to wear the track chain. Track tension monitoring and daily inspections are also important.
According to Antonio Pela’, engineering and product support manager at Berco of America, three factors greatly impact undercarriage wear. These include ground conditions, the operator’s behavior and the correct machine settings. “A sandy environment reduces undercarriage life more than a rocky application,” he comments. “Sharp turns and quick accelerations wear components off way quicker than smooth operation. Finally, every OEM suggests the correct sag for the track assembly group. Over-tensioning the tracks allows more grip, but wears components faster because of the extra friction involved.”
You need to manage what you can control. “There are controllable and non-controllable variables that determine undercarriage life,” says Tim Nenne, undercarriage market professional, Caterpillar. “There is not much that can be done about the application or underfoot conditions, but track tension and the operator are the two biggest controllable factors.”
He adds, “A good operator means everything when you are trying to achieve the lowest life-cycle costs. A good operator controls and considers the amount of unproductive movements of that track-type machine and maximizes every hour and every mile. A good operator controls the amount of track slip and thinks about not turning the same direction all the time; high-speed reverse; operating with the same side of the machine facing downhill all the time. A good operator understands the undercarriage wear and the things he or she can do to reduce it.”
Monitor track tension
According to Nenne, tight track is the No. 1 cause of premature track wear on a dozer undercarriage. When you change applications, run the machine for an hour on the new site and then set the track tension to the correct specification. “Re-check the tension as conditions change. For instance, if it rains overnight or during work hours, that will change the amount of packing — track tension will need to be readjusted,” he advises.
A tight track can substantially increase wear on the idlers, links, bushings and sprockets. “Tight track can also damage the sealing system due to high track joint temperatures,” says Nenne. “It is always better to run a bit on the loose side so that if packing increases, there is some margin of error before damage/increased wear begins.”
“Tight track will also rob useful horsepower and increase fuel consumption,” Boebel adds.
But a loose track also creates problems. “It is too loose when the track starts to drag on the top of the roller frame,” says Nenne.
According to Pela’, a loose track group association can cause derailing, chain popping out from the sprocket, unusual impacts between parts and possible chipping and spalling.
The perfect balance between tight and loose stays within the sag recommended by the OEM manufacturer. This requires regular attention. “During the life of the undercarriage, normal wear on parts will naturally allow the tracks to become loose,” says Pela’.
Understand impact of control movements
“Modern hydrostatic machines allow operators to turn fast and on a small radius, creating additional stress on the undercarriage as the track group assembly is subjected to additional pulling forces coming from the final drive,” says Pela’. “Those extra efforts tighten the track group assembly and increase the wear rate.”