In short. A wheel alignment sets three angles of the suspension back to the car maker's figures: camber (how far the wheel leans in or out seen from the front), toe (whether the wheels point in or out seen from above) and caster (how far the steering axis leans back seen from the side). The signs are a car that pulls to one side, a steering wheel that sits off-centre when you drive straight, and tyres that wear on one edge or with a feathered tread. The tyre makers do not agree on an interval, and none says what its figure is based on: Continental UK says at least once a year on one part of its page and "no fixed interval" on another, Michelin US says annually or after a significant impact, Pirelli UK says there is no set formula. Between them, they name the events that call for a check: a hard hit on a kerb or pothole, new tyres, new steering or suspension parts, and (Continental UK) lowering or raising the car.
The three angles, and what each one does to a tyre
Continental UK calls alignment, also known as "tracking", a mechanical adjustment of the suspension, not of the wheels themselves, that sets the angles of the wheels to the car maker's specification (Continental UK). Three angles matter.
| Angle | Seen from | What it is | What it does when it is wrong | Usually adjustable? |
|---|---|---|---|---|
| Camber | The front or rear | The tilt of the wheel from vertical. Negative: the top leans in towards the car. Positive: the top leans out | Wear on one shoulder: the inner edge with too much negative camber, the outer edge with positive (TNPF; Michelin France) | Often only on some axles; Tesla's Model 3 manual says the car has no dedicated camber adjustment point |
| Toe | Above | Whether the front of each wheel points in (toe-in) or out (toe-out) | The tyre is dragged sideways as it rolls: rapid wear, feathered edges. Pirelli says a major toe error can wear out a tread in a few hundred miles | Yes, on almost every car: it is the adjustment every alignment includes |
| Caster | The side | The backward or forward lean of the steering axis, the line through the upper and lower pivots | Steering that does not self-centre, or a pull if the two sides differ. Little direct tyre wear in the sources we read | Rarely: Pirelli says very few vehicles have adjustable caster |
Positive caster, says Continental UK, improves stability and the self-centring of the steering. Pirelli adds that when caster is out of specification, correcting the thrust line, camber and toe may bring it back; otherwise there is an underlying issue, such as a bent part (Pirelli UK).
The thrust line is the direction the rear axle pushes the car. If the rear wheels are toed unevenly, the car crabs slightly and the steering wheel sits off-centre even when the front toe is right. This is why Continental UK says modern cars almost always need a four-wheel alignment: camber, caster and toe at the front, camber and toe at the rear.
What these small angles mean in millimetres
Alignment figures are given in degrees and minutes (60 minutes to a degree), which says little to most drivers. The following table is our own arithmetic, not a figure from a tyre maker. It takes a toe error per wheel and works out two things: how far the front edge of an 18-inch or 20-inch rim sits out of line compared with its rear edge (rim diameter × tangent of the angle), and how far sideways the tyre would have to slide to keep up while the car runs straight (distance × tangent of the angle).
| Toe error per wheel | Offset across an 18 in rim | Across a 20 in rim | Sideways slide per km | Per mile | Over 10,000 miles |
|---|---|---|---|---|---|
| 0.05° (3') | 0.4 mm | 0.4 mm | 0.9 m | 4.6 ft | about 14 km (8.7 miles) |
| 0.10° (6') | 0.8 mm | 0.9 mm | 1.7 m | 9.2 ft | about 28 km (17.5 miles) |
| 0.15° (9') | 1.2 mm | 1.3 mm | 2.6 m | 13.8 ft | about 42 km (26 miles) |
| 0.20° (12') | 1.6 mm | 1.8 mm | 3.5 m | 18.4 ft | about 56 km (35 miles) |
| 0.50° (30') | 4.0 mm | 4.4 mm | 8.7 m | 46 ft | about 140 km (87 miles) |
The tyre does not really slide over the whole distance: it twists in its contact patch, so the table describes the scrubbing it has to absorb, not a measured loss of rubber, and the wear depends on load, speed and tyre. It does show why a fault invisible to the eye matters: half a degree of toe asks the tyre to scrub sideways for 87 miles every 10,000. Pirelli UK puts it in words: even a minor issue can take thousands of miles off a tyre, and a major misalignment, especially in toe, can wear the tread out in a few hundred miles.
Camber works differently. Our second calculation takes the width of a tread and the camber angle and gives the difference in height between its two edges if the tyre did not deform (tread width × sine of the angle): about 3.9 mm across a 225 mm tread at 1° of camber, 7.9 mm at 2°, 11.8 mm at 3°; across a 245 mm tread, 4.3, 8.6 and 12.8 mm. The tyre flattens on the road, so nothing actually lifts; what the figure gives is an image of how much more load one shoulder carries than the other, which is the wear on one shoulder that the TNPF, the French tyre makers' association, attributes to camber (TNPF, wear damage, in French).
Signs your car needs an alignment, and what else causes them
Continental UK lists five signs: uneven or rapid tyre wear, the car pulling to one side, the steering wheel off-centre when driving straight, tyres squealing in low-speed turns, and vibration in the steering wheel or floor. Pirelli UK adds that you can see the problem in the tread when the car is parked, as one part worn more than another or a difference in depth from the inside to the outside edge. None of these signs belongs to alignment alone.
| What you notice | Angle most often in question | Other causes to rule out first | Sources |
|---|---|---|---|
| Wear on one shoulder only | Camber (negative: inner edge; positive: outer edge) | Hard cornering; worn suspension parts | TNPF; Michelin France |
| Feathered tread, burrs on the rib edges, wear running from one edge to the other | Toe (toe-in or toe-out) | Worn suspension parts | TNPF |
| Facets or patches with noise, mostly on the undriven axle | Geometry and suspension design | Long motorway runs at steady speed; low pressure | TNPF |
| Wear on both shoulders | Not alignment | Under-inflation or overload | TNPF |
| Wear in the centre | Not alignment | Over-inflation, or under-inflation at high speed | TNPF |
| Car pulls to one side | Camber or caster that differs left to right (Michelin France: a camber difference between the front wheels); rear toe (thrust line) | Uneven pressures; a binding brake; a tyre with a construction pull | Continental UK; Michelin France |
| Steering wheel off-centre | Toe, or rear toe and the thrust line | A knock that bent a track rod | Continental UK; Pirelli UK |
| Vibration at speed | Rarely alignment | Wheel balance first | Continental UK (same page) |
The other causes listed for a pull, an off-centre wheel and a vibration are our reading, not the tyre makers' words. Continental lists vibration as a sign of misalignment, then says a steering wheel vibrating at high speed most likely needs balancing. Start with our guide to wheel balancing for a vibration, and check the tyre pressures against the car maker's figures before you blame the geometry for a pull or for shoulder wear.
When to stop and have it looked at. If the steering wheel went off-centre or the car started to pull straight after a hard hit on a kerb or pothole, the impact may have bent a steering or suspension part, not just moved an angle; Continental UK says such a hit can damage the steering linkage. Have it checked before you drive on. To look at the inner edge of a tyre, turn the steering to full lock with the car parked. Never go under a car held only by a jack: if it must be raised, it stands on axle stands on firm, level ground.
How often should you check the alignment?
| Source | What it says about the interval | Events that call for a check |
|---|---|---|
| Continental UK | "at least once a year" in its section on timing; in its FAQ, there isn't a fixed interval that applies to all drivers, and on well-maintained roads alignment usually doesn't need to be checked regularly | Pull, off-centre wheel, uneven wear; new tyres; a pothole or kerb; harsher roads mean more frequent checks |
| Michelin US | Annually, or after any significant impact; alignment does not shift with every rotation | Rotation is a good moment to ask for a check |
| Pirelli UK | No set formula; many mechanics recommend a check at every service | After new tyres, new steering or suspension parts, hard blows or accidents |
| Michelin France | No interval given | When tyre wear is irregular |
None of these pages says what the yearly rhythm is based on, and the same tyre maker gives two answers on one page. Our reading, which your car's handbook overrides: the events in the right-hand column are what move an alignment, so they are when to check it, and a yearly check is a reasonable habit if your roads are poor or you cannot remember the last time. Tyre wear is the slow sign: compare the inner and outer edges each time the tyres are rotated, since rotation spreads wear but does not correct a geometry fault.
What a maker's tolerance window looks like
Car makers publish a target and a tolerance for each angle in their service data. Few are public; Tesla's Model 3 service manual is one. Here is its table for coil-spring cars built 2017 to 2023, as read on 16 October 2026 (Tesla, Model 3 service manual):
| Angle | Front, with 68 kg ballast | Rear, with ballast | Front, without ballast | Rear, without ballast |
|---|---|---|---|---|
| Camber | −0.50° ± 0.45° | −1.00° ± 1.0° | −0.30° ± 0.45° | −0.90° ± 1.0° |
| Camber split (left vs right) | ± 0.60° | ± 0.80° | ± 0.60° | ± 0.60° |
| Caster | 5.70° ± 1.0° | — | 5.70° ± 1.0° | — |
| Toe, each wheel | 0.05° out ± 0.15° | 0.20° in ± 0.15° | 0.06° in ± 0.05° | 0.18° in ± 0.05° |
| Toe split | ± 0.10° | ± 0.10° | ± 0.10° | ± 0.10° |
Three things in this table are worth knowing whatever you drive. Camber has a wide window, up to a degree either way at the rear, while toe without ballast is held to ± 0.05°, the first row of our millimetre table: toe is the angle that wears tyres, so it is set tightly. The split limits the difference between left and right, because a difference is what makes a car pull. And the load changes the target: the manual asks for 68 kg (150 lb) ballast bags in the front seats to simulate a driver and passenger, says the result is less accurate without them, and gives other targets for an unladen car; the front toe moves from slightly out to slightly in. A printout that shows "green" is only as good as the conditions in which it was measured. The manual also says the Model 3 and Model Y have no dedicated camber or caster adjustment points. For the wheels of these cars, see our Tesla Model 3 and Model Y wheel guide.
We found no public alignment figures for BMW or Porsche. Ask the garage for the before-and-after printout, which should show the maker's window next to each value.
New wheels, new tyres, lowered cars
New tyres. Continental UK recommends an alignment check when fitting new tyres, so a new set does not start wearing unevenly; Pirelli says to realign after replacing tyres.
New wheels. The camber, toe and caster are angles of the hub and suspension, so a wheel of a different design bolted to the same hub does not change them by itself. That is our reading, not a maker's statement. A change of width or offset moves the tyre in or out and changes the leverage of the tyre on the suspension (the scrub radius), which can alter how the car steers and whether the tyre clears the arch; our guides to offset and to wheels or tyres rubbing explain it, and the wheel offset calculator shows the change in millimetres. New wheels usually arrive with new tyres, which brings the tyre makers' advice above into play. Onyx Forged does not recommend a size or an offset: the car maker's documents set what the car accepts, and our guide to choosing aftermarket wheels shows where to read them.
Lowered or raised cars. Continental UK says lifting or lowering a vehicle changes the suspension geometry and requires professional realignment. Our reading, not a maker's figure: on many suspension designs the wheel gains negative camber as it moves up into the arch, so a lowered car often sits with more negative camber than standard, and toe moves too; how much depends on the design. Have the alignment done to the maker's figures where they can still be reached; where they cannot, ask the supplier of the suspension parts for its settings, and check the inner shoulders of the tyres often. Our guide to lowering springs and coilovers covers the rest.
What the inspections test
United Kingdom. The MOT does not measure alignment angles. Section 2 of the inspection manual, updated 14 October 2026, lists "Track rod or drag link ends seriously misaligned" as a major defect (2.1.3 (e)), and for fly-by-wire steering checks that the wheels point straight ahead when the steering wheel does (2.6) (GOV.UK, MOT manual, steering). Section 5 catches the consequence: the tread must be at least 1.6 mm deep in the central three-quarters of its breadth, and a tyre whose cords are exposed is dangerous (5.2.3). A tyre worn down on its inner shoulder by camber or toe can fail on either count (GOV.UK, MOT manual, tyres).
United States. We found no federal rule on alignment; inspection is set by each state, and many states have no periodic safety inspection. Pennsylvania's inspection procedure, as one example, rejects a car if "The rear wheel does not track front wheel in straight ahead position as originally designed" ((e)(1)(xiv)) or if the wheelbase on one side differs from the other by more than 1 inch unless the design says otherwise ((e)(1)(xv)), and if a tyre has less than 2/32 inch of tread in two adjacent grooves ((e)(1)(i)) (67 Pa. Code § 175.80). Check your own state's rules.
Australia and Canada. We could not read the texts on 16 October 2026: the federal site hosting Australia's code for vehicle modifications (VSB 14) did not respond, and Ontario's inspection regulation did not display. Roadworthiness is set by each state, territory or province; for a lowered car, ask your transport authority before the work.
Frequently asked questions
What is the difference between alignment and tracking?
In the UK they are synonyms (Continental UK, Pirelli UK). The word can also be used for a front toe adjustment only, so ask which angles are measured and adjusted.
What is negative camber, and is it bad?
Negative camber means the top of the wheel leans in towards the car. Many cars are set with a little of it: Tesla's Model 3 specification is −0.50° at the front and −1.00° at the rear with ballast. It becomes a problem when it is beyond the maker's window, and the sign is wear on the inner shoulder of the tyre.
How often should I get a wheel alignment?
No interval is backed by evidence in the sources: Continental UK gives both "once a year" and "no fixed interval", Michelin US says annually, Pirelli UK no set formula. Check after a hard hit, new tyres, steering or suspension work, lowering, and when the tread wears on one edge.
Can I do a wheel alignment myself?
Pirelli UK says alignment is not a do-it-yourself job and needs proper equipment and trained staff; Continental UK says it should be done by a professional with the proper equipment. You can look for the signs yourself: steering wheel position, a pull on a flat road, and the inner and outer edges of the tread.
Do I need an alignment after new wheels?
New wheels on the same hub do not change the angles by themselves (our reading), but Continental UK and Pirelli UK both advise a check when tyres are replaced, and new wheels usually come with new tyres.
Two-wheel or four-wheel alignment?
Pirelli UK says a front-end alignment is usually for trucks or heavy-duty SUVs with a solid rear axle, and that cars with independent suspension or all-wheel drive need a four-wheel alignment, which covers most passenger cars.
Does the MOT check wheel alignment?
Not the angles. It fails seriously misaligned track rod ends and tyres below 1.6 mm or with cords showing, which is how a bad alignment shows up.
Onyx Forged is a French brand of made-to-order forged wheels, designed to JWL/VIA standards: see how to customise a set.
Sources
- Tyre makers: Continental UK, wheel alignment; Pirelli UK, wheel alignment; Michelin US, tire rotation guide; Michelin France, parallélisme et équilibrage (in French, updated 28 January 2025).
- TNPF, wear damage, the French tyre makers' association (in French).
- Tesla, Model 3 service manual, wheel alignment.
- GOV.UK, MOT inspection manual, section 2, steering and section 5, axles, wheels, tyres and suspension.
- Pennsylvania Code, 67 Pa. Code § 175.80.
All pages were read on 16 October 2026. The millimetre and camber figures are our own calculations, with the assumptions given in the text.
The Onyx Forged design office.