This can result in reduced productivity and higher operating costs. “For example, using an LGP machine with very wide tracks... on very hard/rocky ground would not be recommended,” says Klima. The grousers will be unable to penetrate the ground and the shoes will be at risk of becoming loose and damaged due to the high forces on the track bolts.
“On the other hand, using an undercarriage with less length of track on the ground and narrow shoes in soft ground does not work either,” he continues. “The machine would just sink in and be very hard to operate. Consequently, fuel consumption would increase, as increased power is needed to move the machine.”
As such, he advises, “A good general rule for choosing the right shoe width is go with the narrowest shoe that still supports the machine and go wider only when it’s necessary.”
CUSTOMIZED TO CONDITIONS
“There are over 50 different types of shoes available to fit various applications,” says Klima. “There are shoes ranging from single to triple grousers or even special shoes for swamp applications with better self cleaning.” The shoes can be ordered with trapezoidal holes that allow material to be pushed out through the holes in the center for improved clean-out.
While specialty shoes are offered for steel-tracked excavators, most variations are targeted to crawler dozers. “Due to their higher running time, usually dozers are more sensitive to the track solution that is used,” says Bottin.
Extra-wide shoes for LGP dozers are a common option. “Those shoes are up to 38 in. wide and reduce the ground pressure significantly. This is required in applications where the ground is very soft and the machine is likely to sink in,” says Klima. “If even lower ground pressure is required, swamp shoes can be installed.”
Moderate service, extreme service and even super extreme service shoes are also available. “Extreme service track pads are larger,” says Gilbeck. “Therefore, they offer more life in higher abrasive conditions, as well as provide more grouser penetration into the ground.”
“The higher the thickness of the grouser and shoe, the longer it will last,” Klima points out. “This is especially important in highly abrasive material or on heavier machines running on rock.”
Optional mud holes or clipped corners can further enhance the performance of moderate and extreme service shoes. “Muddy applications — when packing is an issue and can severely stress the components — require shoes with mud relief holes,” says Bottin. “If fine grading is necessary, shoes with clipped corners are recommended.” Clipped corners enable better steering control of the tractor.
Extreme service shoes are more commonly found on larger machines. “Usually, the benefit of these shoes is more evident in larger dozers than in smaller units, where the added cost and the affected smoothness of ride may not justify the choice,” says Bottin.
“On smaller and mid-size machines... extreme service shoes should only be used if required,” Klima asserts. “Extreme service or super extreme service shoes do not penetrate the ground as easily as moderate service shoes do. With that, the ride gets bumpier, the machine can lose traction and the overall grading performance will decrease.”
Extreme service and other specialty shoes are more expensive than standard track shoes. “There is a price premium over standard equipment, ranging from a few hundred dollars to multiple thousands of dollars, depending on the tractor size,” Gilbeck acknowledges.
Yet, the added expense can be worth it under the right circumstances. “The advantages of the non-standard shoes are clearly in the better performance and cost savings in special applications,” says Klima. “Costs associated with the undercarriage are a major contributor to the overall service and maintenance costs on a dozer. It can be 50% or more. Having the wrong track and shoe combination on a machine can dramatically increase the wear and, with it, the cost.”
The track chain type can also have a substantial impact on undercarriage operating costs and uptime. “Using a standard option when the conditions require [a heavy-duty chain] usually leads to premature wear of the components and, in some cases, premature failure due to fatigue,” says Bottin.