Old tyres, six years old and older, can pose a serious risk to your safety. A Tyre Shop recently showed Bettertyres a Dunlop Grand Trek tyre which had been on the back of an Izuzu Wizard for 7 years. The tyre had little wear and seemed to be in good condition but exploded without warning on a hot sunny day, while still mounted on the 4wd’s back door! This happened while the driver and his family were on a sunday drive; as you can imagine, they got a terrible shock.
Tyres start to significantly deteriorate when they are between 6 and 10 years old. The rubber dries out and starts to crack and the steel belts start to rust and eventually they snap leading to a blowout. Sometimes there is a warning in the form of visible cracks, out of shape tyre or vibration from the tyres/steering wheel at low speeds. Other times the tyre will suddenly blow out; you might be driving somewhere or could even happen while you are stationary. The tyre might be on the back door like this one or if you are really unlucky, it might be on the front wheels and explode while you are driving at motorway speed.
Obviously the Warant of Fitness check finds a lot of these faults, but often these age related tyre faults develop between Warants of FitnessTest; this will become a much more frequent problem now that the WOF test intervals have been extended.
Please do not take the risk, replace your tyres after they are 6 years old and definitely before they are 10 years old.