Track slippage and spinning can accelerate shoe grouser wear. Areas affected include sprocket teeth and bushing contact surfaces, track links and roller rails/flanges and idler tread surfaces. "All of the heavy contacts among these parts cause accelerated wear on components," Bottin comments.
The potential repercussions go beyond increased wear. "Track spinning delivers several hits to the bottom line," says Neeley. "It reduces production, so your revenue potential declines... More than a 5% slippage of the track increases undercarriage costs and fuel costs without improving productivity. And it accelerates undercarriage wear, so your costs escalate. Grouser bars are especially prone to wear problems associated with track slippage."
To minimize the potential for track slippage or spinning, Bottin advises operators to carefully consider the ground conditions and the status of grousers while operating. "Furthermore, choosing the right shoe width is important to prevent slippage in all applications," he says. "This should also prevent premature wear and other potential problems."
Working on slopes
"Operating on hills generally accelerates wear because the loads are not distributed evenly on the whole undercarriage, but are carried on by a lower number of components compared to work on flat ground," says Bottin. "Working up- or downhill stresses the rear and the front components (respectively), while working on a slope or side hill shifts the weight and loads on the downhill side of the machine."
If working on hills can't be avoided, the best approach is to alternate the direction of travel as much as possible to even out the wear on undercarriage components.
Keeping the undercarriage clean also helps. "Working on hills tends to accumulate dirt more in some areas according to the direction the machine travels," Bottin points out. "Pressure washing the undercarriage helps in keeping abrasive materials (sand, gravel) from piling up on the contact surfaces of the components, reducing wear accordingly."
Proper frame alignment is also important. "Check periodically to make sure tracks are traveling over the sprocket and idler in the center of the rollers," Bottin advises.
Reverse operation has traditionally been one of the fastest ways to wear out a track. "The only time bushings rotate against the sprocket teeth under load is during reverse operation," Bottin explains. "This can accelerate the wear of sprockets and bushings up to three times compared with forward traveling."
"Operating in reverse, even at slow speeds, compounds bushing and sprocket wear," Neeley adds. "So don't run in reverse unless you have to."
In cases where reverse travel is necessary, Schaefer advises moving the machine just fast enough to maintain production without over speeding. "Some contractors have even locked out the highest reverse gear range to prevent operating the machine faster in reverse than necessary," he notes.
Some of the newer track systems on crawler dozers are more resistant to wear in reverse. "For instance, Caterpillar's SystemOne undercarriage eliminates the significant bushing and sprocket wear that occurs in reverse operation on sealed and lubricated track," Neeley asserts.
However, Schaefer cautions, "While innovations such as rotating bushings reduce the effects of reverse operation on an undercarriage by perhaps as much as 50% to 70%, there is no room in the cab for an untrained operator."
Clean and inspect with each shift
Failure to keep the undercarriage clean can compound problems related to improper track tension.
"Clean-out of tracks is a must," Pooley emphasizes. "If the tracks are too tight when working in muddy conditions, and the operator does not clean the mud out before it dries, the mud will harden and the tracks will become tighter. The sprockets will ride over the hardened mud that is packed in the rails. This will allow tracks to jump when traveling and cause idler and chain failures."
Buildup of mud and debris can also cause components to wear at a faster rate. Consequently, Neeley advises starting every shift with a clean undercarriage.
"If a cleanup didn't happen at the end of the previous shift, take a few minutes to get the job done before you go to work," he suggests. "And if you are operating in very cohesive and abrasive materials like mud or clay, you may need to clean the undercarriage more than once during a shift."