You're halfway through a lesson. Your pupil is driving, concentrating hard on a roundabout approach, doing everything you've taught them. Then there's a bang. The steering pulls hard to one side. For a second, neither of you knows exactly what just happened - only that something has changed, and you have to take control, right now, from the passenger seat.
That scenario is deliberately uncomfortable to read, and it should be. It's also entirely avoidable in the vast majority of cases, because tyre failure rarely happens without warning. It happens after weeks of a tread getting thinner, a pressure staying low, or a bulge being noticed and quietly filed under "I'll look at that properly at the weekend."
The uncomfortable question
When was the last time you actually measured the tread on every tyre on your car - not glanced at it, measured it?
Most instructors would say they check their tyres regularly. Far fewer could say, with confidence, what the tread depth was on each tyre this week. The legal minimum in the UK is 1.6mm, measured across the central three-quarters of the tyre and around its entire circumference - not just at one point. A tyre can pass a casual glance and still be illegal, because wear is rarely perfectly even across the surface.
Being above 1.6mm keeps you on the right side of the law. It doesn't automatically mean the tyre is in good condition. Cuts, sidewall bulges, embedded stones or nails, and incorrect inflation pressure can all compromise how a tyre performs long before the tread depth becomes the limiting factor.
What the numbers actually say
This isn't a hypothetical risk. According to the Department for Transport's most recent road casualty figures, tyre-related casualties of all severities in Great Britain reached 667 in 2025, up 14% on the year before, with 201 people killed or seriously injured in collisions where defective, illegal, or underinflated tyres were a contributory factor. TyreSafe, the UK's tyre safety charity, has also highlighted that DVSA records around 2 million MOT tyre failures every year.
None of that means every worn tyre ends in a collision. It means worn and defective tyres are a measurable, ongoing cause of serious harm on UK roads, at a scale that makes "I'll check it properly at the weekend" a genuinely risky habit rather than a harmless one.
Your pupil doesn't know your tyre is unsafe
This is the part that makes tyre condition different for a driving instructor than for almost any other motorist. Your pupil is a learner. They are trusting you, specifically, to have already taken care of the things they don't yet know to check themselves. They can't assess tread depth from the passenger seat, and they wouldn't necessarily recognise a slow puncture or an underinflated tyre even if they were looking for it.
That trust is part of the job. A daily or weekly tyre check isn't paperwork for its own sake - it's the difference between a pupil learning in a genuinely safe car, and a pupil learning in a car that simply hasn't caused a problem yet.
What a proper tyre check actually covers
- Tread depth - measured across the central three-quarters, at multiple points around the tyre, not just one spot check
- Sidewall condition - no cuts, bulges, or visible cord
- Inflation pressure - checked against the manufacturer's recommended figure, not just "looks about right"
- Embedded debris - stones, nails, or screws that could be working their way through
- Even wear pattern - uneven wear can point to alignment or suspension issues worth investigating further
- Spare tyre - checked too, not forgotten because it's rarely used
Why the "quick check" fails
The reason tyre problems get missed usually isn't negligence - it's that a glance from standing height genuinely can't tell you what a tread depth actually is. A tyre with 2.2mm left and a tyre with 1.4mm left can look identical from three feet away. The only way to know for certain is to measure it, log it, and be able to see how quickly it's dropping - because a tyre losing 0.3mm a month behaves very differently to one that's been stable for a year.
Log a tread depth reading for each tyre at every check, and the app builds a wear history over time - so you can see a tyre approaching the legal minimum weeks before it gets there, instead of finding out the hard way. Combined with the daily walkaround check, it's one habit that covers the whole vehicle.
Frequently asked questions
This article references Department for Transport reported road casualty statistics and TyreSafe/DVSA figures on tyre defects and MOT failure rates, current at the time of writing. It is provided for general information and does not describe a specific reported incident. Always check current guidance on gov.uk.