Wheel Alignment and the MOT: What Is Tested, What Is Not, and Why It Still Costs You Failures

Wheel alignment is not an MOT test item. Section 5 of the DVSA inspection manual for cars and passenger vehicles, which covers axles, wheels, tyres and suspension, contains no requirement to measure toe, camber, caster or thrust angle. What it does test is the consequences of misalignment: tyre tread depth, tyre condition, and the condition of suspension components. A vehicle can fail on those items for reasons that trace directly back to geometry the test never measured.

What the MOT actually inspects

Section 5 of the DVSA inspection manual covers axles, wheels, tyres and suspension. Its sub-sections are axles, stub axles, wheel bearings, road wheel and hub, road wheel condition, tyres, springs, shock absorbers, suspension arms and rods, suspension joints and bushes, gas and air suspension, and the complete suspension system.

There is no alignment measurement anywhere in it. A tester has no obligation to put a vehicle on an aligner.

That boundary is worth being precise about with customers, because the common assumption that "the MOT checks my tracking" is wrong, and the follow-up assumption that "it passed, so my alignment is fine" is wrong in a more expensive way.

The tread depth rule that catches people out

This is where misalignment and the MOT genuinely intersect, and it is the detail most explanations get wrong.

For passenger vehicles with a maximum of eight passenger seats excluding the driver, and for goods or dual-purpose vehicles not exceeding 3,500kg design gross weight, the requirement is 1.6mm of tread depth. But that requirement is qualified in two important ways.

First, it applies to the primary grooves only. Primary grooves are those containing tread wear indicators, or grooves cut as deep as those containing the indicators when new. Secondary grooves and sipes are not counted when assessing tread depth

Second, and more significantly, it applies within the central three-quarters of the breadth of tread, around the entire outer circumference. The manual is explicit that either side of that central three-quarters can be devoid of tread. In its own words, those outer edges can be bald.

The practical consequence for an MOT bay is this. A vehicle running excessive positive or negative camber, or a significant toe error, wears the shoulder first. That shoulder can be worn well past the point of usefulness and the tyre still meets the tread depth requirement, because the shoulder sits outside the measured band. Provided the cords are not exposed or damaged, which is a Dangerous defect under 5.2.3 (d)(ii) in its own right, the tyre passes on tread depth. The customer leaves believing the tyres are legal, which they are, and that nothing is wrong, which is incorrect.

Then the wear migrates inward. Once it reaches the central three-quarters, the defect category is Dangerous. Not a minor, not an advisory. The vehicle that passed at the last test can fail outright at the next one, and the customer's tyres have been consumed at an accelerated rate in between.

Where misalignment shows up on the test result

Defect references are from the DVSA MOT inspection manual for cars and passenger vehicles, section 5. Always work from the current published manual, as categories are revised periodically.

The opportunity sitting in the MOT bay

Every vehicle that comes through for an MOT has all four wheels examined by a technician who is already looking at the tyres. Unless what they see is recordable as a defect or an advisory, it tends to go no further than the certificate.

A shoulder that is wearing faster than the centre, a feathered edge, or a difference between nearside and offside on the same axle are all visible in the seconds a tester already spends on each tyre. None of them are recordable defects on their own. All of them are alignment indicators.

The distinction that matters is between reporting and diagnosing. A tester noting uneven wear as an advisory has told the customer there is a problem without telling them what it is. A workshop that can follow the observation with a measurement has converted a routine test into a diagnosed job with evidence behind it.

The wear pattern itself tells you which direction to look. Our guide to reading tyre wear patterns sets out the common patterns, their likely causes, and which of them an aligner can confirm and correct. It also covers the patterns, cupping in particular, that are routinely misattributed to alignment when the cause is elsewhere.

Two points that are worth stating. Worn suspension components must be replaced before alignment is set, or the settings will not hold. And alignment should be measured on tyres with usable tread, because badly worn tyres distort the readings.

What this needs in the bay

A full four-wheel reading covers toe, thrust, camber, caster and SAI. That separates a geometry fault from a suspension fault from a pressure fault, which is what turns a visual observation into something you can charge for and stand behind.

A standard alignment typically takes five to twenty minutes depending on the vehicle and the system. Computerised systems give the fastest workflow and produce the before-and-after printout that shows a customer exactly what was measured and what was corrected.

Why Choose Supertracker Wheel Alignment Equipment?

Supertracker has been manufacturing wheel alignment equipment since 1987, with over 17,000 systems manufactured and every machine assembled in the UK. Systems are designed to be quick to use and built to last, which matters in an MOT bay where alignment has to fit around test slots rather than replace them.

As part of the Straightset group, Supertracker equipment is supported by a nationwide service engineer fleet, with a full stock of spares and accessories held for short lead times. Laser systems carry a three year structural warranty plus a one year electrical parts warranty. CCD systems carry a twelve month parts warranty. Calibration is recommended at least every twelve months, or after any impact, damage or part replacement, and our engineers use mobile rigs tested to traceable standards.

Prices start from £1,999 + VAT depending on model and configuration. To see a system working on your own vehicles, book a demonstration or speak to our team on 01909 480055.