Wear Blog - Heavy Equipment Parts & Tractor Parts

Published: July 18, 2026 | By FP Smith Parts & Equipment

FP Smith Parts stocks track chains, rollers, idlers, sprockets and undercarriage components for dozers

Regular undercarriage inspection protects one of the most expensive systems on your dozer — and we stock the parts when replacement is needed.

The undercarriage is one of the most expensive systems on any crawler dozer. Tracks, rollers, idlers, sprockets, and related components can account for a large share of long-term operating costs. Regular inspection is the most effective way to control those costs, extend component life, and avoid unexpected downtime. At FP Smith Parts & Equipment, we have helped operators manage undercarriage wear for 79 years. This guide covers what to look for and when to take action.

Why Undercarriage Inspection Matters

Undercarriage components wear gradually. By the time performance is obviously affected, significant life has already been consumed. Catching wear early allows you to:

Plan replacements instead of reacting to failures
Match component wear so you do not replace parts prematurely
Avoid secondary damage (for example, a worn sprocket accelerating track chain wear)
Reduce overall cost per hour

A consistent inspection routine pays for itself many times over.

Key Components to Inspect

1. Track Chains / Links

Look for:

Stretched pitch (measure several links and compare to new specifications)
Worn or cracked bushings
Loose or worn pins
Cracked or broken links

Excessive stretch or bushing wear usually means the chain is approaching the end of its useful life.

2. Track Shoes / Pads

Check for:

Worn grousers (height reduction)
Cracked or broken shoes
Loose or missing hardware
Uneven wear across the shoe

Shoe wear affects traction and can accelerate link and roller wear if left unchecked.

3. Track Rollers (Bottom Rollers)

Inspect for:

Flat spots or uneven wear on the roller surface
Leakage from seals
Worn flanges
Seized or rough-turning rollers

Leaking or seized rollers should be addressed promptly to prevent damage to the track chain.

4. Carrier Rollers (Top Rollers)

These support the track chain on the top side. Look for the same issues as bottom rollers — leakage, flat spots, and rough rotation.

5. Idlers

Front idlers should be checked for:

Surface wear or flat spots
Seal leakage
Proper alignment
Wear on the idler flanges

Worn idlers can cause tracking problems and accelerated chain wear.

6. Sprockets / Segments

Examine:

Tooth wear (pointed or hooked teeth indicate advanced wear)
Cracks
Uneven wear patterns

A worn sprocket will rapidly destroy a new track chain. Sprockets and chains should generally be replaced as a matched set when wear is advanced.

7. Track Adjusters & Recoil Springs

Check for:

Proper track tension
Leakage from the adjuster cylinder
Damaged or broken springs (on models so equipped)
Binding or difficulty adjusting

Incorrect tension is one of the fastest ways to shorten undercarriage life.

Worn sprockets destroy new chains. Always evaluate sprocket condition before installing a new track chain — replace them together when wear is advanced.

Simple Inspection Routine

A practical inspection can be done in a relatively short time:

Park the dozer on firm, level ground and clean heavy mud or debris from the undercarriage.
Walk both sides and visually examine all components listed above.
Measure track pitch and grouser height if you have the tools and specifications.
Rotate the tracks slowly (or move the machine) and listen for unusual noises.
Check track tension according to the manufacturer’s method.
Record findings and hours so you can track wear over time.

Perform a basic visual check daily or every shift in severe conditions. Conduct a more detailed inspection weekly or at regular service intervals.

Common Wear Patterns and What They Mean

Even wear across both sides — Normal for the hours; plan balanced replacement.
One side wearing faster — Check alignment, idler position, or operating habits (constant turning in one direction).
Sprocket teeth hooked or pointed — Replace sprocket before or with the chain.
Rollers leaking or flat-spotted — Replace soon to protect the chain.
Rapid bushing wear — Often related to abrasive conditions, improper tension, or dry pins/bushings.

When Replacement Is Needed

Once wear limits are reached, continuing to operate becomes expensive. FP Smith stocks a wide range of undercarriage components, including:

Track chains and shoes
Bottom and carrier rollers
Idlers
Sprockets and segments
Track adjusters, seals, and related hardware
Pins and bushings

We carry new OEM surplus, quality used, and reconditioned options for many Komatsu, Caterpillar, Dresser, Dressta, International Harvester, and other popular dozer models. Because we maintain physical inventory, many common items are available for same-day shipping.