by Jesse Crosse
Published at HAGERTY, Insurance for classic cars and motorbikes, with the friendly support of Calum Brown
Spring is in the air, and we will all be aching to get out and about either a short blat, long road trip or booking onto a track day. Tyres are like other consumables you don’t want to spend money on them, but they are very important. Hanging on to an older set of tyres may be just about acceptable on a wire-wheeled classic that never exceeds 50mph but on anything younger and faster, it can be dangerous.
It’s often said that the only thing between the car and the road are those four, small contact patches and the type and quality of tyre you choose can have a big impact on grip, handling, braking and steering feel. From a safety point of view, just because your car is a much-loved toy that you cherish and drive only for fun, it doesn’t mean that 15 year-old tyres are OK because they’re not.
4-digit date codes have been moulded on tyre sidewalls since 2000. The first two digits signify the week and the second two, the year. So ,0617 would mean the tyres were made in the sixth week of 2017.
Most manufacturers agree tyres should be replaced at seven to 10 years and while tyres that age are less likely to be found on a daily driver, low annual mileage cars could well be shod with older rubber. It should go without saying that inspection is important.
You should look for tell-tale signs that all is not well, such as uneven wear across the tread of the tyre. This can indicate incorrect wheel alignment and will manifest itself as wear on only one side of the tyre, with the outside of the tyre wearing due to toe-in, and the inside due to toe-out. Any reputable tyre fitter and many garages will be able to investigate further and make corrections to the vehicle manufacturer’s recommended setting.
Any damage to the sidewall is a no-no and cracking or crazing – both on the sidewalls and between the blocks of tread – is a dead giveaway that the compound is suffering from the effects of UV radiation, oxidisation and weathering. Again, it’s time to get rid. That recommendation holds true irrespective of the visual condition of the tyre and even if they appear to be perfect, they should be replaced once they’re past the manufacturers use-by date. After all, how can you be certain that the tyre’s construction won’t fail and it will suffer delamination of the tread and plies, quite possibly at speed?
Don’t forget to check tyre pressures regularly as well, only when the tyre is cold, because pressure affects the performance of a tyre especially if it’s a performance car. Also remember that more often than not, a car has recommended air pressures for light loads and another set for heavy loads or for most of us high-speeds – and don’t forget the spare wheel, if the car has one.
When checking air pressures, avoid filling station air lines and don’t trust a foot pump gauge. To get it right, it’s worth investing in a karting pressure gauge from a motorsport supplier. A racing kart is super sensitive to tyre pressures and gauges made for that purpose must be very accurate. Set tyre pressures cold for road use but if you drive your car on track days and are using dedicated track day or race tyres, check they are at the optimum recommended pressure when hot to get maximum grip.