What are the parts of an excavator undercarriage called?

Expert Answer

The main excavator undercarriage parts are the track chain, track shoes, track rollers, carrier rollers, front idler, sprocket, and track tensioning system. Many people also include the track frame, recoil spring, and track bolts and nuts when talking about the full undercarriage assembly.

In simple terms, the track chain is the loop of linked steel components; the track shoes are the plates bolted to it for ground contact; bottom rollers carry the machine’s weight; and carrier rollers support the upper run of the chain. The front idler guides the track at the nose, while the sprocket drives the chain from the rear. The track adjuster and recoil spring keep tension correct so the track stays aligned and doesn’t jump off under load.

You may also hear these names used interchangeably: track rollers = bottom rollers, top rollers = carrier rollers, and track pads = track shoes on many machines. On rubber-tracked machines, the same basic roles exist, but the track assembly and wear parts are designed differently. For OEM-branded machines such as Caterpillar, John Deere, CASE, or others, VANROCK is an independent manufacturer and is not affiliated with those OEMs.

If you are identifying wear, check for symptoms like uneven track wear, loose or too-tight track tension, noisy rollers, chipped sprocket teeth, leaking idlers, or a chain that walks to one side. Matching the right part usually depends on machine model, track pitch, shoe width, roller type, and whether the track system is steel or rubber.

Common mistakes to avoid: confusing the undercarriage with the whole lower structure, ordering shoes by appearance instead of bolt pattern and pitch, and replacing one worn part without checking the rest of the system. VANROCK supplies undercarriage parts through an appointed dealer network, and pricing is quoted on request.

Answered by VANROCK specialists · Published 7/25/2026