A wheel is being held on by fewer fixings than it should be, or one of them isn't doing its job. It sounds trivial next to a corroded subframe, but a wheel coming off at speed is one of the worst failures there is, so it's marked hard.
Wording as it commonly appears on an MOT certificate: “Wheel nut or stud missing or insecure”.
What does it mean?
A wheel is being held on by fewer fixings than it should be, or one of them isn't doing its job. It sounds trivial next to a corroded subframe, but a wheel coming off at speed is one of the worst failures there is, so it's marked hard.
How serious is it?
Usually recorded as: Major, Dangerous. The tester assesses the actual vehicle on the day, so your certificate is what counts.
What normally causes it?
- A stud stretched or snapped by an air gun over-tightening it
- A cross-threaded nut from a rushed tyre change
- A rounded or seized locking wheel nut that nobody could remove, so it was left off
- Corroded alloy nut caps swelling so the nut can't be torqued properly
What a mechanic would check
I check every fixing with a torque wrench rather than a rattle gun, and I look at the seat of each nut — a nut sitting proud or a shiny witness mark around the hole means it isn't seating. If a locking nut is rounded I'd rather remove it properly and fit a full set of standard nuts than pretend it's fine.
What might need replacing
- Wheel nuts or bolts
- A wheel stud, which usually means removing the hub
- A locking wheel nut removal set
- Torque-checking all four wheels
Can you still drive it?
This can be recorded as Dangerous. Don't drive with a missing or loose fixing — vibration builds quickly and the remaining studs fail one after another.
Repair cost
Nuts and studs are cheap parts; the cost is in getting a seized locking nut off without damaging the alloy.
Before the retest
Check every tyre, not just the one that failed — the legal minimum is 1.6mm across the central three-quarters of the tread, all the way round. Make sure tyres on the same axle match in size and construction, and that all wheel nuts or bolts are present and tight. Set pressures to the figure on the door shoulder or in the handbook the morning of the retest.
Retest rules
If the vehicle stays at the test centre for repair and is retested within 10 working days, a partial retest is often free; some items qualify for a free retest if you bring the car back by the end of the next working day. The exact conditions are set out on GOV.UK, so confirm with the test centre before you leave. A major or dangerous failure means the car cannot legally be driven away unless the previous MOT is still valid and nothing dangerous was recorded — check your certificate first.
Related help
More tyres and wheels failures · MOT failure decoder · Ask a mechanic about your certificate
This is general guidance from a UK mechanic, not a substitute for a physical inspection. Only the tester who inspected your vehicle can confirm what was recorded and why.