IRREGULAR TYRE WEAR 101

Identifying and diagnosing irregular tyre wear early is critical to keeping your prime movers and trailers on the road, minimising downtime, and maximising your cost per kilometre. Below is a breakdown of common irregular wear patterns across steer, drive, and trailer tyres, along with their probable causes and corrective actions.

DEPRESSION WEAR

(INTERMEDIATE)

APPEARANCE
One or more interior ribs (not centre) depressed more than adjacent ribs.

PROBABLE CAUSE
Incorrect air pressure, worn mechanical part, or nonuniformity such as mismount.

CORRECTIVE ACTION
Check air pressure and mechanical issues.

TYRE DISPOSITION
Rotate or retread.

DIAGONAL

WEAR

APPEARANCE
Manifests in the form of oblique wear patches. Can appear singularly or repeat around the circumference of the tyre.

PROBABLE CAUSE
Misalignment, radial and lateral runout, severely out of balance, loose wheel bearings or steering parts.

CORRECTIVE ACTION
Check for mismount and worn parts.

TYRE DISPOSITION
Reverse direction of tyre or retread.

MULTIPLE FLAT

SPOTTING WEAR

APPEARANCE
Multiple radially worn areas around the tyre.

PROBABLE CAUSE
Faulty shocks, loose/worn wheel bearings, severe balance issues, mismatched pressures or tyre diameters, excessive high-speed empty operation.

CORRECTIVE ACTION
Check for mechanical issue; check air pressure.

TYRE DISPOSITION
Continue to run or retread.

FEATHERING 

(THREAD EDGE)

APPEARANCE
Feathering at the edge of the tread ribs.

PROBABLE CAUSE
Usually the result of continued exposure to lateral force, such as excessive toe. Can also form as a result of counter-steering to compensate for drive axle misalignment.

CORRECTIVE ACTION
Check alignment

TYRE DISPOSITION
Rotate to another position or retread.

DEPRESSION WEAR

(SHOULDER)

APPEARANCE
Localised wear patch on the shoulder rib of the tyre. This patch can repeat around the circumference of the tyre.

PROBABLE CAUSE
Faulty shocks, lateral runout, loose wheel bearings, mismount, severe balance issue.

CORRECTIVE ACTION
Check for mechanical problem.

TYRE DISPOSITION
Continue to run, rotate or retread.

DEPRESSION WEAR

(CENTRE)

APPEARANCE
Circumferential depression wear of the centre tread rib.

PROBABLE CAUSE
Overloaded or underinflated, faulty shocks, loose wheel bearings, mismount, or high-speed empty running/ unladen conditions.

CORRECTIVE ACTION
Check air pressures or load weight and worn parts.

TYRE DISPOSITION
Continue to run, rotate or retread.

IRREGULAR TRAILER TYRE CONDITIONS

DEPRESSION WEAR

(SHOULDER)

APPEARANCE
Interior ribs or localised shoulder areas (generally less than 300 mm in length) worn below adjacent ribs.

PROBABLE CAUSE
Worn suspension, mismatched dual diameters/pressures, underinflation, or incorrect wheel bearing adjustment. Aggravated by high speeds and light loads.

CORRECTIVE ACTION
Review tyre and wheel end maintenance practices.

TYRE DISPOSITION
Continue to run until pull point, then retread.

SHOULDER

STEP WEAR

APPEARANCE
Tyre worn on the edge of one shoulder, covering more than 300 mm of the circumference.

PROBABLE CAUSE
Excessive camber, misaligned or damaged axle, improper bearing adjustment.

CORRECTIVE ACTION
Diagnose misalignment and/or mechanical condition and correct.

TYRE DISPOSITION
Reverse direction of rotation. If excessive, submit for retreading.

CUPPING /

SCALLOP WEAR

APPEARANCE
Random areas of fast wear around the tyre. Erratic in some instances.

PROBABLE CAUSE
Mismatched inflation pressure or tyre diameters in a dual assembly. Aggravated by high speeds/light loads, poorly maintained suspension components.

CORRECTIVE ACTION
Check inflation pressures and matching tread depths.

TYRE DISPOSITION
Continue to run until pull point, then retread.