Inner edge tyre wear: geometry, not the tyres

Inner edge wear is the most expensive wear pattern to ignore, because it is invisible. From outside the car the tyre looks fine; the worn band is on the inside face, and it can reach the cords while the rest of the tread still has depth.

Check the inner edge by hand. Reach behind the wheel and feel across the tread. This is the check that finds it.

Related: tyre rotation and wear patterns.

The two geometry causes

Excessive negative camber

Camber is the wheel’s lean when viewed from the front. Negative camber means the top leans inward, so the inner edge carries more load.

Some negative camber is designed in — it improves cornering grip. Too much wears the inside.

Causes: worn suspension components, a sagging or broken spring, impact damage, or a car deliberately lowered without corrective geometry.

Suspension modification electronics.

Toe out of specification

Toe is whether the wheels point slightly inward or outward viewed from above.

Incorrect toe is the more aggressive wear cause of the two. A wheel pointing a fraction of a degree wrong is dragged sideways every metre travelled, which scrubs the tread continuously.

The signature of a toe problem is feathering: run a hand across the tread in both directions. Smooth one way and sharp-edged the other means toe.

Wheel balancing vs alignment and wheel alignment and steering angle.

Why the geometry went out

Alignment does not drift on its own. Something changed it.

Worn suspension components

Bushes, ball joints, track rod ends. As they wear, the wheel’s position under load moves away from where it was set.

Aligning a car with worn components is wasted money — the geometry is correct on the ramp and wrong on the road.

Suspension bushes wear symptoms and rattling noise over bumps.

Impact

Kerbs and potholes. A single significant hit can bend a component or move a subframe.

If wear started after a specific impact, that is the cause: pothole damage: what to check and after a minor accident, what to check.

Ride height changes

Lowering springs change camber and toe as a side effect. Without corrective adjustment, inner edge wear follows.

Equally, sagging springs on an older car lower it unintentionally with the same result.

Rear axle geometry

Often overlooked. Rear toe out of specification wears rear tyres exactly this way, and it also forces the front wheels to compensate.

A front-only alignment cannot detect it. Ask for four-wheel alignment.

The cost of not looking

Inner edge wear reaches the cords while the visible tread still passes a casual glance.

A tyre worn to the cords can fail suddenly at speed, and in many jurisdictions it is an immediate inspection failure and a penalty.

The financial cost compounds too: a set of tyres destroyed early by a geometry fault that would have cost a fraction to correct.

Making the check a habit

Once a month, run a hand around the inner edge of each front tyre. Thirty seconds, no tools.

What you are feeling for:

Sensation	Meaning
Even depth across the tread	Healthy
Noticeably less depth on the inside	Camber or toe
Sharp edges one way, smooth the other	Toe — feathering
Scalloped patches	Worn dampers or imbalance
Wear on both edges, centre fine	Underinflation
Centre worn, edges fine	Overinflation

What the vehicle can tell you

Little directly, since tyre wear is not sensed.

Indirectly: TPMS catches the pressure-related patterns, and steering angle data reveals a car tracking straight with the wheel off centre — which points at geometry: steering wheel off centre.

Where to start

1. Feel the inner edges of all four tyres.
2. Check pressures against the placard.
3. Check for play in suspension joints before aligning.
4. Get a four-wheel alignment with a printout.
5. Recheck the wear after a few thousand kilometres to confirm the fix.

Try it on the free tier of the app — pair an ELM327 adapter and check the steering angle value with the wheels straight. A non-zero reading points at geometry that was never set correctly.