TIRE WEAR PATTERN LIBRARY

VISUAL SIGNATURE

Center tread blocks worn smooth or significantly thinner than the outer shoulders. Tire profile looks rounded across the tread face. Wear is symmetric left-to-right.

ROOT CAUSE

Overinflation. Pressure too high stretches the carcass and lifts the shoulders off the road, putting all the load on the center contact patch. Common when owners read sidewall max pressure as recommended pressure (sidewall max ≠ door placard spec).

REPAIR SCOPE

Set to door placard spec at cold temperatures (typically 30–35 psi for passenger cars, 35–45 for light trucks). Educate customer on cold-pressure checking. Rotate tires; if center wear is severe, replacement is needed but always check TPMS calibration too.

VISUAL SIGNATURE

Both outer edges (inside and outside shoulders) worn significantly more than the center tread. Tire profile looks dished or hollow in the middle. Same pattern on both sides of the same axle.

ROOT CAUSE

Underinflation. Pressure too low lets the carcass flex; the center lifts off the road and the shoulders take the load. Causes heat buildup (sidewall flex = friction) which accelerates wear and risks belt separation. Often paired with a slow leak the customer ignored.

REPAIR SCOPE

Find the leak source (valve stem, bead seal, sidewall puncture, slow porosity). Inspect for internal separation — heat-damaged tires can look intact externally but have broken belts. Replace TPMS sensors if older than 7 years (lithium batteries die). Customer education on monthly pressure checks.

VISUAL SIGNATURE

Inboard edge (facing the vehicle) worn down to wear bars or cords. Outboard edge has nearly full tread depth. Asymmetric wear from inside to outside. Often shows on one tire of an axle, not both.

ROOT CAUSE

Excessive negative camber (top of wheel leaning in) or toe-out at that corner. Comes from worn ball joints, sagged spring, bent control arm, collision damage that wasn't measured, or simply an alignment that's drifted out of spec. Lowered vehicles run this pattern routinely without compensating camber kits.

REPAIR SCOPE

Full 4-wheel alignment with camber and SAI/IA measurements. If SAI is in spec but camber is out, you have a bent strut or knuckle that no adjustment will fix. Inspect ball joints, control arm bushings, and ride height before aligning. Replace worn parts first, then align.

VISUAL SIGNATURE

Outboard edge (facing away from the vehicle) worn down significantly. Inboard edge has nearly full tread depth. Mirror image of inner-edge wear. Often shows on one corner more than the others.

ROOT CAUSE

Excessive positive camber (top of wheel leaning out) or toe-in at that corner. Comes from sagged or weakened springs (vehicle settled), bent strut/spindle, raised vehicle without alignment correction, or sustained heavy loads in trucks/SUVs without re-aligning afterwards.

REPAIR SCOPE

Measure ride height before aligning — sagged springs throw camber out without any other fault. Inspect upper strut bearing and mount. Full alignment with camber and SAI verification. If lift kit was installed, check whether alignment was done after.

VISUAL SIGNATURE

Bowl-shaped depressions repeating around the circumference, evenly spaced every few inches. Tire feels rough when run by hand. Often makes a loud humming/droning road noise that customers complain about before they notice the visual pattern. Usually on rears of front-drive cars.

ROOT CAUSE

Suspension component not damping properly — tire bounces in and out of contact with the road. Sources: worn struts/shocks (the most common), severe wheel imbalance, worn upper strut mount bearing, broken or worn strut spring. Less commonly: worn ball joints or tie-rod end allowing wheel to skip.

REPAIR SCOPE

Bounce test all four corners. Replace worn struts/shocks as axle pairs. Replace strut mounts with the struts (always — bearings fail too). Rebalance all four wheels with road-force or Hunter equipment. Cupped tires often need replacement; they won't smooth out.

VISUAL SIGNATURE

Each tread block has one sharp vertical edge and one sloped/ramp-shaped edge, alternating consistently across the tread width. Run your palm across the tread — smooth one way, catches the other way. Both fronts usually show it together.

ROOT CAUSE

Toe alignment is off — wheels are not pointing exactly straight ahead. Tire is being dragged sideways slightly with every revolution, scrubbing material off one edge of each block. Toe-in feathers outboard; toe-out feathers inboard. Even small toe errors (0.10° or less) produce visible feathering over thousands of miles.

REPAIR SCOPE

Full alignment with toe set carefully. Inspect tie-rod ends for play, rack mounts, inner tie-rod sockets. If feathering is severe enough to cause noise (which it often is), the tires may need replacement — the rough surface won't smooth out. Customer gets quoted alignment + possibly tires.