How to Identify Worn Undercarriage (With a Real 7,400-Hour Example)

Undercarriage wear is one of the biggest hidden costs for any excavator or dozer owner. In BC terrain like rock, sidehill work, winter freeze thaw cycles, and slash, wear shows up faster than most operators expect. The key is knowing where to look and what the real indicators are.

Below is a quick guide to the three critical wear zones on a track chain, followed by a real-world example: a 7,400 hour Hitachi ZX370 road builder running a six-year-old ACE undercarriage that is still functioning, still tracking, and still holding tension.

Face wear, side rail wear, and pin boss wear. These three areas tell you the true condition of your chain.

Three Wear Points Every Operator Should Watch

These areas determine chain life, pitch alignment, and whether your undercarriage is still serviceable or ready for replacement.

• Face wear. This is where the rollers ride. Thin or scalloped faces cause rough tracking and vibration.

• Side rail wear. Controls alignment. Tapered or uneven rails make the machine walk or side-load the rollers.

• Pin boss wear. Affects pitch. Once the pin bosses begin to oval out, the chain stretches and starts damaging sprockets.

These three measurements matter more than rust or appearance.

Despite the rust, the pin bosses, bushing ends, and rail faces are still holding their shape.

Real Example. 7,400 Hour ZX370 on a Six-Year-Old ACE Chain

This is a typical BC machine: steep ground, granite rock, winter work, and long periods parked outside. The chain is rusty, but the wear surfaces tell a different story.

What the photo shows:

• Pin bosses are still round with no collapse

• Bushing ends are not mushroomed or hammered

• Side rails have even wear

• No cracked hardware or loose bolts

• Sprocket wear is reasonable for the hours

This chain is near the end of its life, but it is still tracking straight and holding tension. Rust alone does not tell you whether a chain is worn out.

Original track shoes after 7,400 hours. No cracking, no folding, and the grousers are still usable.

Track Shoes Confirm the Story

The original shoes have also held up extremely well after six years and thousands of hours.

The shoes show:

• Good grouser height

• No cracked corners or folded edges

• Even pad face wear

• Tight bolt holes with no wallowing

• Shoes that have outlived the chain

A balanced undercarriage system should wear evenly, and this machine is a perfect example.

The Takeaway

Identifying worn undercarriage is straightforward when you know what to look for. Focus on:

• face wear

• side rail wear

• pin boss wear

• bushing ends

• sprocket tooth shape

• track shoe condition

  
  

This ZX370 shows how a high-quality chain can stay functional for years, even when it looks rough on the outside.

If you want help assessing your own rails, send a photo of your link faces, pin bosses, and sprocket. We will give you a clear answer about whether you can keep running it, rebuild it, or plan a full replacement. You can send photos by text direct to Rob @ 250-318-7887 or email to sales@interiorundercarriage.ca.

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