Written by City Wheels · G-10/1, Islamabad
- tyre-care
- safety
- guide
Replace a tyre when its tread reaches the wear indicators, when it is around six years old, or immediately if you see a bulge, a deep cut or cracking in the sidewall. Uneven wear and new vibrations are also warnings — they usually point to an alignment or balancing problem that will ruin the next set too.
1. Is the tread worn down?
Every tyre has tread-wear indicator bars moulded into the grooves. When the tread is worn level with those bars it is at about 1.6 mm — the legal minimum in many countries and the point at which the tyre must go. In practice, grip on wet roads falls away sharply well before that, from around 3 mm, so plan to replace before you reach the bars if you drive on wet roads or at motorway speed.
2. How old is the tyre?
Rubber ages whether or not the tyre is used. Read the four-digit DOT date on the sidewall (for example 1522 = week 15 of 2022). Many tyre professionals recommend replacing tyres at about six years old, and manufacturers generally advise that no tyre should stay in service beyond ten years from manufacture — including the spare.
3. Are there cracks in the sidewall?
Fine cracking, often called crazing, is a sign that the rubber has aged and dried out. Strong sun and heat accelerate it. Light surface crazing on an old tyre means replacement is due soon; deep cracks you can press a fingernail into mean it is due now.
4. Is there a bulge or blister?
A bulge on the sidewall means the internal structure has been damaged, usually by hitting a pothole or kerb. The tyre can fail without warning. Stop driving on it at speed and replace it — a bulge cannot be repaired.
5. Do you feel a new vibration?
A vibration through the steering wheel or seat that appears at a particular speed is usually a balancing issue, but it can also be a tyre with internal belt damage or a flat spot. Have it checked before assuming the tyre is fine.
6. Is the tread wearing unevenly?
The pattern tells you the cause:
| Wear pattern | Likely cause |
|---|---|
| Both edges worn, centre fine | Running under-inflated |
| Centre worn, edges fine | Running over-inflated |
| One edge worn (inside or outside) | Wheel alignment out |
| Patchy, scalloped dips | Unbalanced wheel or worn suspension |
Replacing a tyre without fixing the cause means the new one wears the same way. A wheel alignment check costs far less than a set of tyres.
Should I replace two or four?
If the others still have good tread and are a similar age, replacing two is fine — fit them as a pair on the same axle, and put the new pair on the rear. If your tyres are close to the end or more than about five years old, replacing all four at once gives the most predictable handling. See our tyre range or bring the car in and we will check all four for you.
Questions answered
Can I check tread depth without a gauge?
Yes — look for the small raised bars across the bottom of the main grooves. If the tread surface is level with them, the tyre is at its limit. A tread-depth gauge is inexpensive and gives a precise reading if you want to track wear.
Does the spare tyre need replacing too?
Yes. A spare ages like any other tyre even if it is never used. Check its DOT date and pressure when you check the others, and replace it if it is old or cracked.
