A car is designed for its wheels to sit at precise angles. Get those angles right and it tracks straight, steers cleanly and wears its tyres evenly. Let them drift, and the car pulls, the steering wanders and one edge of a tyre quietly scrubs away. Alignment is the job that puts the angles back where the maker intended.
What it sets
Wheel alignment adjusts the angles the wheels sit and point at, back to the vehicle manufacturer's specification. Three angles do the work, each covered in the guide to toe, camber and caster:
- Toe: whether the wheels point slightly in or out, seen from above
- Camber: how far the wheels lean in or out at the top, seen from the front
- Caster: the angle of the steering pivot, seen from the side
Of these, toe is the one most often out and most often adjusted; camber and caster matter more on some cars than others.
How it is done
Alignment is measured on dedicated equipment, laser or camera-based rigs that read each wheel's angles and compare them against a database of the maker's figures for that exact car. The fitter then adjusts the suspension's track rods and, where the car allows, the camber, until the readings match spec. It is a measured, to-the-figure job, not a visual guess.
What knocks it out
Alignment drifts for ordinary reasons:
- Potholes, kerbs and speed bumps taken hard, the most common cause
- Worn suspension parts, which let the angles wander
- Normal mileage, which nudges the settings slightly over time
- Suspension or steering work, after which alignment should always be rechecked
Because impacts do most of it, a single bad pothole can be enough to put a car out, which is why a jolt worth wincing at is reason enough for a check.
Not the same as balancing
The job most often mixed up with alignment is wheel balancing, and the two are different:
- Alignment sets the angles, fixing pulling and uneven wear
- Balancing sorts the weight of a wheel and tyre, fixing vibration
A vibration is balance; a pull or one-sided tyre wear is alignment. A car can need both, but neither fixes the other.
Why it is worth doing
Correct alignment pays back in three ways: tyres that wear evenly and last their full life, a car that tracks straight and steers cleanly, and slightly better fuel economy, since misaligned wheels scrub and drag. Against the cost of a tyre ruined early, an alignment check is cheap insurance, the signs it is needed are usually showing well before the tyre is gone.
From the workshop: the pothole season after winter is alignment season. The roads break up, people clout a few, and a month later the tracking's out and the inner edges are wearing. A check after a hard hit saves the tyre, waiting until you can see the wear means it's already too late for that tyre.
Sources and accuracy. The description of alignment and what affects it reflects standard industry practice at the time of writing; the car's own specification is the reference figure. If anything here looks wrong, get in touch and we will check it and put it right.
Common questions
What is wheel alignment?+
Adjusting the angles the wheels sit and point at, back to the car maker's specification. Correct alignment means the wheels point true, so the car tracks straight, steers cleanly and wears its tyres evenly rather than scrubbing them.
What knocks a car's alignment out?+
Everyday impacts, mostly, potholes, kerbs and speed bumps taken hard. Worn suspension parts can shift it too, and it should always be checked after suspension work. Even normal mileage drifts the settings slightly over time.
Is wheel alignment the same as balancing?+
No. Alignment sets the angles of the wheels so the car tracks straight and tyres wear evenly. Balancing corrects the weight distribution of a wheel and tyre so it spins without vibration. They are separate jobs that are often confused.
How often should wheel alignment be checked?+
There is no fixed interval, but a check is worth doing once a year, after fitting new tyres, after any suspension work, and any time the car starts pulling or wearing a tyre unevenly. A pothole hard enough to jolt the car is reason enough on its own.