Tyre Age & DOT Codes: What to Check Before You Buy

Tread depth gets all the attention in a quick tyre check, and it's the easiest thing to glance at — but it's only half the picture. Rubber compounds harden and crack with age and UV exposure whether or not the tyre has done many kilometres, which means a tyre with plenty of visible tread can still be an unsafe, ageing tyre. The only reliable way to know how old a tyre actually is sits in plain sight on every sidewall, and almost nobody checks it.

Reading the DOT code

Every tyre sold has a Department of Transport (DOT) code moulded into the sidewall, ending in a four-digit number. Read it like this:

• First two digits — the week of manufacture (01–52).
• Last two digits — the year of manufacture.

So a code ending in 2319 means the tyre was made in week 23 of 2019. If you find a code ending in only three digits, that indicates a tyre made before 2000 under the older date-code format — treat any tyre that old as needing replacement regardless of how it looks.

Why age matters even with good tread

Rubber compounds harden over time through oxidation and UV exposure — a process that continues whether the car is driven daily or sits mostly parked. Hardened rubber grips less effectively, especially in the wet, and is more prone to cracking and sudden failure, particularly on tyres that have also seen years of heat-cycling from driving. A tyre can retain generous tread depth while the rubber underneath it has already aged past a safe point.

South Africa's legal tread depth minimum

South African road traffic regulations set a minimum tread depth of 1mm across the tyre for most passenger vehicles. This is the bare legal minimum for a roadworthy tyre, not a safety recommendation — wet-weather braking distance increases substantially well before tread reaches that limit, so most safety guidance points to replacing tyres at a noticeably higher tread depth than the legal floor.

What to check on a used car

1. Read the DOT code on all four tyresCheck each one individually — a mismatched set with tyres of very different ages is common on used cars and worth knowing about.
2. Check the spare tooA spare tyre often sits unused for years and can be far older than the tyres actually in service — don't assume it's a safe fallback without checking.
3. Look for crackingFine cracks in the sidewall or tread grooves are a visible sign of ageing rubber, in addition to the date code.
4. Measure tread depthA simple tread depth gauge or the coin test gives you the wear side of the picture, alongside the age check.

What replacement tyres cost

Tyre prices in South Africa vary enormously by size, brand tier and vehicle type — a small hatchback's tyres cost meaningfully less than a bakkie's or SUV's. If you find aged or worn tyres during a pre-purchase check, get an actual quote for your specific tyre size from a local fitment centre and use it as a genuine negotiating point on the purchase price, not just a mental note.

Common mistakes

• Judging tyre condition on tread depth alone and skipping the DOT code entirely.
• Assuming a low-mileage car automatically has young tyres.
• Forgetting to check the spare, especially on cars where it's rarely been used.
• Not using the actual replacement cost as leverage in price negotiation when tyres are found to be old or worn.

Frequently asked questions

This guide is general information for South African motorists, not official confirmation. Tyre ageing guidance varies by manufacturer, and legal tread depth requirements can change. Always check current regulations and your specific tyre manufacturer's recommendations before making a safety decision.