“It’s important to match the wear rate of the shoes to the other wear components of an undercarriage to maximize uptime,” adds Gilbeck. “In many applications, sealed and lubricated track links are all that is required. In sandy soil, an extended life bushing may be required to match the wear rate of the shoes, rollers, idlers and sprocket segments.”
Sealed and lubricated track chain is the most common type used for dozers. “Those tracks normally have a very good life span — proper maintenance assumed,” says Klima. “Sealed and lubricated tracks reduce bushing wear due to the lubrication. This type of track is also not very sensitive to high impacts or other external forces.”
However, this track chain is not well suited for use in highly abrasive material. If the bushing is pressed into the chain link and can’t rotate, it can create friction between the sprocket and the bushes while the machine is traveling. This can cause wear.
“The more abrasive the material, the higher the wear,” says Klima. “This wear can be reduced by using tracks with free-turning (rotating) bushes. Free-turning bushes reduce the friction between the sprocket and the bushing itself to a minimum. With that, wear is reduced and track components wear out more equally.”
Free-turning bushes have their drawbacks, however. “Not only are track chains with free-turning bushes more expensive than sealed and lubricated tracks, they are also much more impact sensitive,” Klima cautions. “In high-impact applications, the seals on tracks with free-turning bushes can fail much easier than on sealed and lubricated tracks.”
As with shoes, there is no one size fits all solution. But the closer you can get to matching a shoe and chain combination to the application, the better.
“The better an undercarriage fits an application, and the better it is maintained, the lower the cost,” says Klima. “With all the different options in undercarriage types, it can be difficult for a contractor to choose the right one. This is especially true if the machine is frequently moved from one application to the next.”
It’s natural to want to get the most out of the money you spend on an undercarriage. Yet, you need to evaluate the various options carefully.
“Depending on the application, track chains with rotating bushes can increase the bushing and overall undercarriage life. But just increasing bushing and undercarriage life might not save cost overall,” Klima states. “Some undercarriage systems with rotating bushes require special tools to service/split the tracks. Also, not all manufacturers allow a change easily between the sealed and lubricated tracks vs. the tracks with rotating bushes.”
Again, this is where future usage requirements come into play. “If a customer decides after having a system with rotating bushes to change to a sealed and lubricated track, it can get very expensive,” says Klima. “Therefore, the machine application has to be reviewed in detail before a decision is made. This will save cost later on.”