Track Chains, Excavator Chains and Undercarriage Chains

What Is a Track Chain?

A track chain consists of track links, pins, bushings and, depending on the design, sealing and lubrication systems. In the undercarriage industry, complete chains are commonly referred to as track chains, while the individual chain sections are known as track links.

The track chain forms the foundation of a crawler undercarriage. Track shoes are mounted to the chain and transfer the machine's operating weight to the ground.

Chain Pitch and Number of Links

Chain pitch and link count are critical when selecting a replacement track chain. The chain pitch defines the distance between the chain joints and must match the sprocket, idler and overall undercarriage geometry.

The number of links determines the overall chain length. Even within the same machine series, different link counts, master links or undercarriage configurations may be used. Manufacturer and model information alone are therefore often insufficient for correct identification.

Oil-Lubricated, Grease-Lubricated and Sealed Dry Track Chains

Track chains differ primarily in the design of the pin-and-bushing system.

• Oil-lubricated track chains: commonly used on dozers and heavy crawler equipment. Lubrication is retained within the joint assembly to reduce wear between pins and bushings. These chains are often associated with SALT (Sealed and Lubricated Track) technology.
• Grease-lubricated track chains: widely used on hydraulic excavators and combine internal lubrication with sealing systems within the chain joint.
• Sealed dry track chains: incorporate sealing systems but do not use permanent internal oil or grease lubrication.

The appropriate chain design depends on machine type, operating conditions and manufacturer specifications.

Master Links, End Links and Repair Links

Depending on the chain design, split master links, master pins, hammer-lock pins or press-fit pins may be used. These components influence chain installation, removal and maintenance procedures.

Hammer-lock pins and split master links can simplify installation and servicing on compatible chain assemblies. However, the selected components must always match the specific chain design.

Repair links and replacement track links are available for repairing individual sections of a track chain. Correct chain pitch, master link design and chain specification are essential for compatibility.

Typical Track Chain Wear Patterns

Wear primarily occurs within the pin-and-bushing assembly. Common indicators include chain elongation, excessive joint play, damaged seals and irregular undercarriage operation.

Worn sprockets, rollers or idlers can also increase chain wear. For this reason, the condition of the complete undercarriage should be evaluated during maintenance and repair work.

Track Chains as Part of the Undercarriage System

Track chains do not operate as standalone components. They function as part of a complete crawler undercarriage system. The chain travels around the sprocket and idler, is supported by track rollers and carrier rollers, and is tensioned by the track adjuster.

Wear affecting one undercarriage component frequently influences other components within the system. During undercarriage refurbishment, the complete undercarriage should therefore be evaluated rather than replacing individual components in isolation.

Related product categories include Track Shoes, Sprockets, Idlers, Track Rollers, Carrier Rollers, Track Adjusters and Bolts & Nuts.

Track Chains from LIS®

The LIS® range includes oil-lubricated track chains, grease-lubricated track chains, sealed dry track chains as well as repair links and replacement track links for a wide range of excavators, dozers, crawler loaders and specialised crawler machines.

Since chain pitch, link count, master link design and undercarriage configuration can vary even within the same machine series, identification using the LIS® Undercarriage Finder is recommended.