How Tyre Age Affects Safety: Reading the DOT Date Code
Tyres age and degrade over time regardless of how much they are used, as the rubber hardens and can crack. You can read a tyre's age from the DOT code on the sidewall: the last four digits give the week and year it was made. An old tyre can be unsafe even with plenty of tread, so age matters as well as wear.
Why tyres age even unused
Rubber is not permanent. Over the years, exposure to oxygen, UV light, heat and the stresses of being parked cause the compound to harden and develop fine cracks, a process called perishing.
This happens whether or not the tyre is used, which is why mileage alone is not a complete guide to a tyre's condition. A barely-used tyre can still be past its best simply because of how old it is.
How to read the DOT date code
Every tyre carries a DOT code on the sidewall, ending in four digits that tell you when it was made. The first two are the week of the year, and the last two are the year itself.
For example, 2620 means the 26th week of 2020. It is quick to check, and well worth a look when buying a used car, a part-worn tyre, or before relying on a spare or caravan tyre you have not used in a while.
When does a tyre become too old?
There is no single legal expiry date for car tyres, but the rubber's condition is what matters. As a guide, tyres should be inspected closely once they are several years old, and many manufacturers and safety bodies suggest considering replacement somewhere around six to ten years regardless of tread.
- Inspect tyres over about six years old at each check.
- Consider replacing at around ten years even with good tread.
- Caravan and trailer tyres are usually advised to be changed every 5 to 7 years.
Signs an old tyre is past it
You can often see age catching up with a tyre. Look for fine cracks (crazing) in the sidewall and between the tread blocks, a hard, shiny look to the rubber, and any deformation or flat spots from long storage.
An old tyre may have legal tread but grip noticeably worse, especially in the wet and cold, because the hardened compound cannot deform and key into the road the way fresh rubber does. If a tyre looks aged, have it assessed even if the tread is fine.
Which tyres are most at risk
Age affects some tyres more than others. Spare wheels, caravan and trailer tyres, classic and second cars, and any low-mileage vehicle are the usual candidates, because the tyres rack up years far faster than miles.
A spare that has lived under the boot floor for a decade, or a caravan tyre with full tread but seven summers behind it, can be the one that fails when you finally need it. These are exactly the tyres worth checking the date code on.
Get older tyres checked
If your tyres are several years old, or you are not sure of their age, bring the car in and we will read the date codes and inspect the condition. We will tell you honestly whether they are still fine, worth watching, or due for replacement on age.
It is a quick, free check that can prevent an aged tyre letting go at the worst moment. When the time comes, we can fit fresh tyres and dispose of the old ones responsibly.
Frequently Asked Questions
How do I check the age of my tyres?
Look for the DOT code on the sidewall, ending in four digits: the first two are the week and the last two the year of manufacture. So 2620 means the 26th week of 2020. It is worth checking when buying a used car or part-worn tyre, or before relying on a spare or caravan tyre.
When should I replace tyres because of age?
There is no single legal expiry, but tyres should be inspected closely once several years old, and many makers suggest considering replacement around six to ten years regardless of tread. Caravan and trailer tyres are usually advised to be changed every 5 to 7 years.
Can old tyres be unsafe even with good tread?
Yes. Rubber hardens and cracks with age, so an old tyre can grip noticeably worse, especially in the wet and cold, even with plenty of tread. It can also be more prone to sudden failure. That is why age matters as well as tread depth when judging a tyre's safety.
Why do tyres age even if I rarely drive?
Rubber degrades with exposure to oxygen, UV light, heat and the stresses of being parked, a process called perishing, which happens whether or not the tyre is used. So a low-mileage car, spare or caravan can have aged tyres that need replacing before the tread runs out.
Which tyres are most affected by age?
Spare wheels, caravan and trailer tyres, classic and second cars, and any low-mileage vehicle, because they rack up years far faster than miles. A spare that has sat for a decade or a caravan tyre with full tread but several summers behind it can fail when you finally need it.
Book With Norwich Tyres & Auto Service
Need a hand from a real, independent Norwich garage? Call 07933 900901 or pop into Ber Street, NR1 3ES. Same-day tyre fitting is available on most common sizes, with free parking on site.
Hero image: “Tyre Safety Roadshow in Canterbury, UK” by First Stop - Bridgestone's UK tyre retail network (source), licensed under CC BY.