1. Measure Chain Pitch
Chain pitch is the distance between pin centers. As pins and bushings wear, the pitch lengthens. Park the machine on level ground and use a tape measure to check the distance across four track links (five pins). Compare to the new pitch specification stamped on the chain. If the measurement exceeds the wear limit (typically 3–5% over new pitch), the chain is stretched. A stretched chain will damage the sprocket and idler — plan for replacement soon.
2. Inspect Track Shoe Thickness
Track shoes wear down from abrasion. On rocky ground, shoes lose thickness faster. Measure the shoe thickness at the center of the grouser (the raised bar). Replace shoes when thickness falls below 70% of original. Worn shoes lose traction, increase slippage, and reduce digging efficiency. Also check for cracked or bent shoes — they can break off and cause track derailment.
3. Check Track Shoe Bolts
Loose or broken track shoe bolts are common and dangerous. Walk around the machine and visually inspect every bolt. Use a wrench or torque wrench to check tightness — typically 300–500 Nm depending on size. If you find a loose bolt, torque it to specification. If you find a broken bolt, replace it before the shoe comes off. Mark each bolt head with a paint line after torquing; a shifted line indicates loosening.
4. Inspect Sprocket Teeth and Idler Flanges
Worn sprocket teeth and idler flanges accelerate chain wear. Look at the drive sprocket — teeth should have a gradual curve, not a hook shape. Hooked teeth dig into the chain bushings, causing rapid wear. Also check the idler flange (the guide rails). Worn flanges allow the chain to wander, causing misalignment. Replace sprockets or idlers when wear exceeds the manufacturer's limits.
Quick field check: After a long shift, walk behind the machine and look at the track chain from the side. If you see visible sagging between the top rollers and sprocket, tension is too loose. If the chain is tight against the track frame, tension is too tight. Proper sag is typically 30–50mm between the bottom of the track frame and the track.
Want an undercarriage wear measurement guide for your excavator? Reply with your model and track serial number — we will send a PDF with pitch limits, shoe wear limits, and a daily inspection log.
