The 20Y-30-00110 is a track roller (sometimes called a carrier roller or track undercarriage roller) used in a very popular family of Komatsu excavators. Numbers in the 20Y series appear across the Komatsu undercarriage catalogue, and 20Y-30-00110 specifically is a part that shows up whenever track frames are serviced or rebuilt. Because undercarriage components experience the harshest wear on any excavator, understanding this roller is genuinely useful for anyone running Komatsu machinery.
This article explains what the 20Y-30-00110 does, which machines it commonly fits, how to inspect it for wear, and how to choose a replacement that will hold up in the field rather than failing early.
What is a track roller and what does 20Y-30-00110 do?
A track roller is the steel wheel that rides on the top and/or bottom of the track chain. On most excavators there are two general types. Carrier rollers support the upper run of the track chain between the idler and the sprocket, while the track rollers (track undercarriage rollers) at the bottom support the weight of the machine on the ground. The 20Y-30-00110 is a track roller within the undercarriage running gear of Komatsu excavators such as the PC200 series.
Each roller carries significant load as the machine travels, rotates and digs, so it is built as a hardened steel wheel sealed around a bearing assembly. The roller has to keep the track chain tracking correctly, distribute the machine’s weight evenly across the shoes, and survive impacts, grit and water. When a roller wears or its seals fail, the whole track assembly starts to work harder and tracking can become unstable.
Which Komatsu machines use the 20Y-30-00110?
The 20Y-30-00110 is most widely associated with the Komatsu PC200 hydraulic excavator series and closely related models that share the same undercarriage frame. The PC200 is one of the best-selling hydraulic excavators ever built, with many thousands of units and variants in operation around the world, which is exactly why demand for its undercarriage parts remains high and why this part number is searched so often.
Because the PC200 family spans multiple serial number ranges and regional configurations, the exact layout of the undercarriage can differ between versions. All track rollers on the same frame are usually the same part, but you should always verify your machine’s serial number against the Komatsu parts book to confirm that 20Y-30-00110 matches the roller position you are replacing.
Understanding the undercarriage track roller layout
The typical PC200 undercarriage uses a fixed number of bottom track rollers on each side, spaced evenly along the track frame, with the sprocket at the rear and the idler at the front. Each bottom roller is mounted between the two rails of the track chain and takes a share of the machine’s loaded weight. When these rollers start to wear flat, the machine begins to ride roughly and the effective ground pressure distribution changes across the shoes.
Signs of a worn or failed track roller
- Flats or eccentric wear visible on the roller’s outer running surface.
- Grease or oil leaking from the roller seal, which lets dirt in and bearings out.
- A rumbling or grinding noise from the undercarriage while travelling.
- Excessive play or wobble when the roller is lifted and shaken by hand.
- Visible scoring, pitting or corrosion of the hardened surface.
A roller that spins smoothly with firm, even resistance when turned by hand and shows a clean, round running surface is normally healthy. Flat spots, roughness and any play in the bearing are the signs that replacement is due. Because worn track rollers accelerate wear on the track chain and bushings, replacing them promptly protects more expensive components further down the line.
Inspection and measurement
To inspect a track roller properly you should clean the running surface, measure its diameter at several points around the circumference with a caliper, and look for a difference between the ends and the middle that indicates conical or stepped wear. You should also check the seal area for leakage and rotate the roller to feel for notchiness in the bearing.
If you are rebuilding an undercarriage, replace the rollers as a set on each side rather than a single roller, because matching diameters keep the track chain running evenly. New rollers fitted alongside heavily worn ones will carry a disproportionate load while the new parts bed in.
Choosing the right replacement roller
The quality of a track roller comes down to the hardness and depth of case on the running surface, the grade of the bearings and seals, and the accuracy of the mounting dimensions. A premium replacement for 20Y-30-00110 should match the OEM roller in diameter, width, bore size and bolt pattern so it fits without rework. Racer Machinery supplies qualified 20Y-30-00110 track rollers and the surrounding undercarriage parts for Komatsu excavators, and we cross reference each part to the Komatsu OEM number before it ships.
Undercarriage maintenance tips
Simple habits extend the life of every undercarriage component. Keep the track frames free of packed mud that hides wear, grease interior rollers on schedule with the specified grease, tension the track to the manufacturer’s recommendation, and inspect the running surfaces for flats after working on hard, abrasive ground. A regular walk-around check that takes a few minutes equals hours of saved work time later.
Conclusion
The Komatsu 20Y-30-00110 track roller is a workhorse part inside the running gear of a very popular excavator. Knowing what it does, which machines it fits, and how to spot wear early keeps your track chain and frame aligned and your machine stable under load. Racer Machinery carries reliable, cross-referenced track rollers and full undercarriage kits for Komatsu and other brands, with worldwide shipping for workshops and fleets.
