MOT & ROADWORTHINESS · LAST REVIEWED: JUNE 2026
TL;DR: A tyre slightly damaged cracking or perishing advisory means the tester saw surface cracks or ageing in the rubber that have not yet reached a failure point. The car passed, but the tyre should be watched, because perishing tends to worsen and can become a major defect.
A note reading tyre slightly damaged cracking or perishing on an MOT certificate describes the condition of the rubber rather than the tread. As an advisory it means the tester judged the damage to be below the threshold for a fail, so the vehicle passed, but the tyre is flagged as a component worth monitoring.
Rubber ages whether or not a car is driven, and cracks can appear in the sidewall or between the tread blocks. Understanding why this happens helps an owner decide when an advisory is routine and when it is a sign that replacement is approaching.
KEY FACTS
- An advisory is not a failure: the vehicle passes, but DVSA records the item as worth monitoring before the next test.
- Tyres are assessed under the DVSA MOT inspection manual, which sets separate criteria for advisory, major and dangerous tyre defects.
- Cuts, bulges or exposed cords, or a tyre worn below 1.6mm of tread, are recorded as major or dangerous defects rather than advisories.
- The current defect grades of dangerous, major, minor and advisory were introduced in May 2018.
- Driving without a valid MOT can bring a fine of up to £1,000 under the Road Traffic Act 1988.
What the cracking or perishing advisory means
Perishing is the gradual breakdown of the rubber compound, which shows up as fine cracks in the sidewall or in the grooves of the tread. It is caused by exposure to sunlight, heat, ozone and the simple passage of time. A tyre can have plenty of tread left and still be perishing, which is why this advisory often surprises owners of low mileage cars.
When a tester records the tyre as slightly damaged, cracking or perishing, they have judged the cracks to be superficial rather than deep enough to expose the structure of the tyre. That keeps it on the advisory side of the line, but the note serves as a documented warning that the rubber is ageing.
When it becomes a failure
The advisory crosses into a major or dangerous defect when the damage is severe enough to threaten the integrity of the tyre. Cracks deep enough to reach the cords, a bulge in the sidewall, exposed ply or cords, or a cut above the limits in the inspection manual are all failures rather than advisories.
Age alone does not have a fixed legal limit for most vehicles in the MOT, but the condition does. A perished tyre that develops a bulge or splits can fail at the next test, and it can also become unsafe between tests, so the advisory is a prompt to keep an eye on it.
Why testers record it and what to do
Testers log the advisory so the owner has a documented record of a part that is deteriorating but not yet failing. The note also appears on the vehicle MOT history that anyone can check online, which gives a used car buyer a view of how the tyres have aged.
A perished tyre is replaced rather than repaired, because the cracking affects the rubber across the tyre and cannot be reversed. Any tyre work should be carried out by a competent fitter, and tyres are usually changed in line with the vehicle handbook so that grip remains balanced across an axle.
Why rubber perishes and how to slow it
Perishing is a chemical process as much as a physical one. The compounds that keep tyre rubber flexible break down when exposed to ultraviolet light, heat and ozone in the air. A car parked outside in strong sun, or close to equipment that produces ozone, can show cracking sooner than one kept in a garage. Short journeys and long periods of standing also play a part, because tyres benefit from being warmed and flexed in use.
The age of a tyre is moulded into the sidewall as a four digit code showing the week and year of manufacture. A tyre that is several years old can be perfectly serviceable, but the code gives context when cracks appear, especially on a spare or a low mileage car where the original tyres may be much older than the mileage suggests.
Slowing perishing is mostly about storage and use. Keeping a car out of constant direct sunlight, maintaining the correct tyre pressures so the rubber is not over stressed, and using the vehicle regularly all help. None of this reverses cracking that has already formed, which is why an advisory is a signal to plan rather than ignore.
When a perished tyre is replaced, it is sensible to check the others on the car, because tyres of a similar age and exposure often perish together. Replacing across an axle in pairs keeps grip balanced, and the new tyre's manufacture date can be noted so its age is known from the outset.
The spare tyre deserves a mention of its own, because it can be the most perished tyre on the car. A full size or space saver spare that has sat untouched for years is exposed to the same heat and ozone as the others while never being used, so it can crack badly even with full tread. A spare in poor condition will not show up in normal driving, but it matters at the moment it is needed, which is reason enough to check its condition and age when an advisory prompts a look at the other tyres.
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DISCLAIMER: This guide is general information, not professional advice. MOT rules and fees are set by the DVSA and can change. Check gov.uk for current requirements before acting.
Frequently Asked Questions
What does a tyre cracking or perishing advisory mean?
It means the tester saw surface cracks or ageing in the tyre rubber that have not yet reached a failure point. The car passed, but DVSA has flagged the tyre as a component to monitor and likely replace before the cracking worsens.
Is a perished tyre an MOT failure?
Not on its own at the advisory stage. It becomes a major or dangerous defect, and a fail, when the cracking is deep enough to expose the cords, or when there is a bulge, exposed ply or a cut beyond the limits in the inspection manual.
How long can I drive on a tyre with this advisory?
The MOT stays valid for its full term, so there is no legal cut-off tied to the advisory. Perishing tends to worsen with time and exposure, so the tyre should be inspected again before the next test and replaced if cracks deepen or a bulge appears.
Can a tyre with good tread still perish?
Yes. Rubber ages whether or not the car is driven, so a tyre with plenty of tread on a low mileage car can still crack or perish. Condition and tread depth are assessed separately in the MOT.
