Undercarriage & wear parts
Excavator sprocket replacement: what to measure and when it is due
A worn sprocket does not fail on its own — it destroys the chain with it. Replacing the sprocket late usually means replacing the chain too, which is why the wear check matters more than the part price.
Three things to establish before ordering
- Tooth count. Count the teeth. A sprocket with a different tooth count will not run correctly on the same chain pitch, regardless of whether it physically fits.
- Chain pitch. Measured across several links divided by the link count. The sprocket and chain must match on pitch.
- Bolt pattern and mounting — segmented versus one-piece, bolt count, bolt circle.
When a sprocket needs replacing
- Hook-shaped teeth. The tooth profile wears into a hook. Once the hook is pronounced, chain engagement is poor and the chain wears rapidly.
- Wear on the tooth face beyond the specification — the tooth gets thinner in section, not just shorter.
- Chain climbing or jumping. This is a late symptom; by the time it happens the chain is usually also worn.
The rule people get wrong
Replace the sprocket before or with the chain, never after. A new chain running on a worn sprocket wears out prematurely — the worn tooth profile acts like a file on the new bushings. A new sprocket on a worn chain is less damaging, but still not correct.
Model-specific notes
Sprockets differ between machine generations and regional builds even within one model family. The model name narrows the search; it does not confirm the part. Machine serial number plus measured tooth count and pitch is what confirms it.
What we need to quote a sprocket
- Machine make, model, serial number
- Tooth count
- Chain pitch
- Segmented or one-piece, bolt count
- Photo of the existing sprocket including the tooth profile
Send to alfrun@gmail.com — we confirm the part number and fitment basis before quoting.
Before you order
Send machine make, model, serial number and a photo of the casting mark. We confirm the part number and fitment basis before any price discussion.
Symptom to cause: sprocket or chain?
| Symptom | Likely cause | What to do first |
|---|---|---|
| Teeth hooked over at the tip | Sprocket wear beyond limit | Replace sprocket with or before the chain, never after |
| Chain climbing or jumping the sprocket | Late-stage sprocket wear, usually with a worn chain too | Expect to replace both — check chain pitch first |
| New chain wears out very fast | Running on a worn sprocket | The hook profile acts like a file; replace the sprocket |
| Chain tight on one side, loose on the other | Alignment, not the sprocket | Check alignment before buying parts |
| Excessive noise but even tooth wear | Chain pitch, not the sprocket | Measure pitch across several links |
A symptom is not a diagnosis. Confirm with measurement before ordering a part — a new component on an unfixed cause fails the same way.
Trademark notice
Machine brand names and part numbers are used only to describe fitment and application. We are not an authorised dealer of any machine manufacturer.
Reviewed by Zhonglei M&E parts desk — export trading partner for undercarriage and wear parts. Last updated 2026-11-13.