When it comes to the undercarriage on steel-tracked machines, “making do” with the inappropriate track shoes and chain can prove costly.
“Using the wrong steel track shoe and chain combinations can dramatically decrease the overall performance and efficiency on the one hand, and cause damage/shorter life of the undercarriage components on the other hand,” says Robert Klima, product manager - crawler tractors, Liebherr Construction Equipment.
Yet, it’s not always practical, or even feasible, to match the track setup for every situation an excavator or dozer may encounter.
“The decision for a certain undercarriage is a compromise in most instances, especially in small and mid-size machines that frequently move from job to job and work in different applications and different materials,” says Klima. “For nearly every application you can think of, there is a ‘right’ shoe type available. However, as machines get moved from one job to another, conditions change. A shoe that might have been a good solution on one job might not be the best solution on another job.”
As such, it’s important to look beyond the current application. “End users are required to always make their choices with future usage in mind,” says Guido Bottin, vice president of operations (COO), Berco of America, “considering that the overall cost of repairing and/or maintaining the undercarriage may reach around 60% of the total operating costs on a mid-size dozer.”
A Question of Width
“Each OEM usually has offerings such as standard track, wide track and low ground compaction (LGP),” says Jon Gilbeck, crawler dozer global product marketing manager, John Deere Construction & Forestry. “Shoes range from 16 to 36 in., depending upon the tractor model.”
According to Klima, undercarriages range from standard track gauge over wide tracks to LGP versions. “This is then combined with different track frame lengths, which determine the length of the track on the ground,” he notes.
The selection of a wider shoe usually is based on the need for additional flotation on rough, soft and uneven ground. Machines working at an angle also benefit from wider shoes on LGP track. “The wider track gauge provides superior stability while operating on side hills and slopes,” says Gilbeck. “The longer track and wider pads provide the maximum level of machine support on the ground surface.”
For dozers, this can mean improved grading characteristics for finish grading, especially when working on uncompacted base fill material. “The larger contact area associated with the wider pads and longer track frame improves the blade control,” Gilbeck explains. “In this configuration, the blade will have less of a tendency to porpoise and allow the operator to have a smoother finishing pass.”
Narrow shoes are better suited to hard soil and rocky conditions. “In a rocky application, a narrow width shoe is appropriate vs. a LGP shoe,” says Gilbeck. “Having a narrow shoe in a rocky application lowers the stress on the entire undercarriage and maximizes the life.”
Both wide and narrow shoes have pros and cons. “Wider shoes are certainly going to provide a smoother ride and more flotation with a lower ground pressure, while the narrower ones will provide better soil penetration and grip to the machine,” says Bottin. “On the downside, larger shoes are definitely more demanding in terms of wear (especially when turning) and oil life on the undercarriage, while using shoes that are too narrow can lead to sinking of the unit, which can cause severe stress on the drive system.”
As a compromise, manufacturers recommend using the narrowest shoe practical for the situation. “As a general rule, the choice of the shoes should be the narrowest possible according to the weight of the machine, type of soil and applicable local regulation for ground pressure,” says Bottin. “Unfortunately, despite this recommendation, the tendency is to use wider shoes than necessary, mainly for smoother ride purposes and to keep the unit more versatile.”