Alignment comes down to three angles, each describing the wheels from a different viewpoint: from above, from the front, and from the side. Knowing what each one does explains both how a car handles and why a tyre wears the way it does.
Toe: seen from above
Toe is whether the wheels point slightly inward or outward when viewed from above. Imagine standing with toes turned in (toe-in) or splayed out (toe-out).
Toe is the angle that matters most for everyday driving and is the one most often adjusted:
- It strongly affects straight-line stability, a car with correct toe tracks true
- It is a leading cause of feathered wear, where tread blocks wear sharp on one side and smooth on the other
- Even a tiny error scrubs the tyres with every mile, so it wears rubber fast when wrong
This is why a basic tracking adjustment deals with toe, it is the setting that drifts most and costs most in tyres when out.
Camber: seen from the front
Camber is how far a wheel leans in or out at the top, seen from the front. Leaning in at the top is negative camber; leaning out is positive.
A small amount of negative camber is designed in on many cars to improve grip in corners, because the tyre sits flatter against the road when the car leans. The trouble comes with too much:
- Excess negative camber wears the inner edge of the tyre
- Excess positive camber wears the outer edge
One-sided wear, especially on the hard-to-see inner shoulder spotted when reading the wear pattern, is the classic camber sign. Whether camber can be adjusted depends on the car, some allow it, many do not without extra parts.
Caster: seen from the side
Caster is the angle of the steering pivot seen from the side, the lean of the line the wheel turns around. It is the least visible of the three and the one drivers feel rather than see.
Caster gives the steering its stability and self-centring: the way the wheel wants to return to straight after a corner, and the planted feel at speed. Importantly, it rarely wears tyres, its job is handling, not wear. On many cars caster is not adjustable, set by the suspension design, which is why it features mainly in a full geometry setup rather than a routine alignment.
Which ones matter for tyres
For tyre wear, two of the three do the damage:
- Toe: feathered wear, and the most common culprit
- Camber: one-shoulder wear when excessive
- Caster: mainly handling, little direct wear
So when a tyre is wearing unevenly from alignment, toe and camber are where the answer lies, and putting them right before fitting new rubber is what stops the damage repeating.
Read the alignment report in context
A factory specification usually permits a range rather than one perfect number. The car must be set up and measured under the appropriate conditions, and worn components can make readings unreliable. Ask which angles were measured, which were adjusted and why any remain outside tolerance. Do not assume a green toe reading rules out a camber or mechanical issue. On a modified car, resolve the intended specification with a competent specialist rather than applying an arbitrary setting from another vehicle.
Common questions
What is toe on a car?+
Toe is whether the wheels point slightly inward or outward when seen from above, like standing pigeon-toed or splay-footed. It is the angle most often adjusted, because it strongly affects straight-line stability and is a common cause of feathered tyre wear.
What does camber do?+
Camber is how far a wheel leans in or out at the top, seen from the front. A slight inward lean helps cornering grip. Too much, especially negative camber, wears the inner edge of the tyre and is a common cause of one-sided wear.
What is caster angle?+
Caster is the angle of the steering pivot seen from the side. It gives the steering its stability and self-centring feel, the way the wheel returns to straight after a turn. It rarely affects tyre wear and is often not adjustable.
Which alignment angle wears tyres?+
Toe and camber are the tyre-wearers. Incorrect toe feathers the tread, and excess camber wears one shoulder. Caster mainly affects how the car steers rather than how the tyres wear, so it is less of a wear concern.