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How do you know which tyre to choose when one needs replacing?

How do you know which tyre to choose when one needs replacing?


Motoring journalist, John Swift tell you everything you need to know about choosing tyres.

Let’s be honest and say that for most of us tyres are just round, black rubbery things that we never bother with unless we have a puncture or they wear out and need replacing. But with around one in ten M0T failures being tyre-related it makes sense to know how to choose your next new tyre because it is important to select the right fit rather than just go for the cheapest option.

Many websites will help you so you need to do is enter your vehicle’s registration number and from that they can access the DVLA data and recommend the correct size of tyre.

But what are you buying? If you look at a tyre you will see various numbers and letters embossed around the sidewall and these give you all the information you need. It’s important to get it right too because there is one letter in particular that could make the difference between being insured or not….

The first thing you will see, and need to know, is a group of letters and numbers around the edge of the tyre which on a typical family car may be arranged like as something like 255/55 R18  105V

markings on a tyre sidewallIn this case, the 255 refers to the tyre’s width in millimetres. The `55’ is what is called the aspect ratio, the ratio of its height to the width of the tread which here is 55%. There is a small gap to the next piece of information, R18, where the R stands for radial, the type of construction most modern tyres have, and 18 which is the internal diameter measured in inches.

Many people look no further because so long as they replace say, a 255/55 R18 with another of the same dimension, that is all they care about but in fact there are two more absolutely critical markings which, as we say, can make the difference between being insured or not.

Because after another small gap you will see numbers – normally between 70 and 110 for an average family car or small SUV – which is the load rating and tells you the maximum weight each tyre can safely carry. You can refer back to an index which would tell you that in this case the 105 refers to a maximum load of 925 kgs. It is critical that you choose one suitable for your car and recommended by the car manufacturer. If you fit one not designed to cope with the weight of the vehicle and it has a blow out followed by a crash, you may well find your insurer won’t honour the policy…

The same goes for the last letter, in this case V, which is the speed rating.  Here the V refers to 149 mph which is the absolute maximum speed the tyre is designed to cope with.

Common speed ratings range from `S’ which is suitable for cars with a top speed of up to 113 mph all the way through to `Y’ where the top speed of the car is up to 186 mph! For cars with 200+ mph max speeds, the tyres are rather more specialist but it is not a choice many of us will have to make.

Moving further around, you may find perhaps `XL’ (extra load) which means the tyre is reinforced. 3PMSF indicated it is certified as a winter tyre, M+S means it is a `mud and snow’ tyre and you sometimes find these on SUVs, and you can also find the date when the tyre was manufactured so you know how old it is.

To discover this you should see the symbol DOT raised on the sidewall – it means Department of Transportation – followed by another set of numbers with the last four showing the year and week. If, for example, it ends with 3112 that would mean the tyre was made in the 31st week of 2012.

One final thing – your car may have all the latest safety aids and you may be a very good driver but always bear in mind that the steering, cornering, accelerating and braking are all ultimately dependent on those four tiny bits of rubber probably no bigger than the palm of your hand which are the only points of contact between the vehicle and the road.

Choose your next set of tyres carefully.


EU label guides.

Since 2012 all new tyres have had to carry a sticker similar to those you find on domestic white goods such as a refrigerator showing energy consumption and in the case of tyres it lets buyers make an informed choice about two basic elements. The labels are clearly marked from A to G where A is the best and G the worst and are divided vertically into two halves. One looks at the tyre’s grip on a wet road and the other its rolling resistance which is a good indicator of how much energy – fuel, in other words – it needs to be rolled over the road surface.

EU label showing fuel efficiency and wet weather performance ratingsIn many cases a tyre `A’ rated for wet weather grip will not have such good marks for rolling resistance but there are plenty which get B for both.

Of the two we say that the wet weather performance is the more important indicator to consider because it doesn’t really matter how much fuel a tyre saves you in running costs if you have no grip and have to pay for repairs after a bump. 

We tell you what to do if your tyre warning light comes on