A4 · Suspension & Steering≈ 7 minThe tire is a witness
01 The Concept
A worn tire is a signed confession — the pattern tells you what's wrong.
Before you touch the alignment rack, read the tires. Where a tire wears — and how — points straight at the cause: inflation, a camber angle, toe, or a worn suspension part. Learn the handful of patterns and you'll diagnose half of A4's suspension problems from the parking lot.
⚑ Feel, don't just look
Some patterns hide from your eyes. Run your palm across the tread: sharp edges one direction = feathering from toe. Dips you can feel around the tire = cupping from worn dampers. And always check inflation first — it mimics camber wear.
02 The Wear Reader
Tap a wear pattern. The tread shows where it wears, and the reader calls the cause and the fix.
03 What If…
Reason first, then reveal.
?A tire is worn on both outer edges with good tread in the center. Camber problem?
No — that's underinflation. Low pressure lets the shoulders carry the load and the center lift. Both edges is the tell; camber wears only one edge. Check and correct pressure before you blame alignment.
?You run your hand across the tread and it feels smooth one way, sharp the other. What's that, and what caused it?
Feathering — and it's toe. The tire is scrubbing sideways as it rolls, shaving a sawtooth into each rib. Set toe to spec (tie rods). Excess toe-in and toe-out both feather; the direction of the sharp edge hints which.
?One front tire is worn only on the inner edge, inflation is correct, toe is good. Cause?
Excess negative camber on that corner — the tire leans in at the top and rides its inner edge. Correct camber (cams/slots/offset ball joint), and check for a worn or collapsed part that let camber drift.
04 Practice
ASE-style. Pick an answer to see why.
05 Recap
Both shoulders worn = underinflation. Center worn = overinflation.
One edge = camber (outer = too positive, inner = too negative).
Feathered / sawtooth (feel it) = toe. Set with the tie rods.
Cupping / scallops = worn shocks or struts, imbalance, or a loose part.
Check inflation first — it fakes camber wear on both edges.