How to look after your vehicles tyres
Your tyres are arguably the most important parts of your car yet so often overlooked. They are the four points of contact with the road - each contact area just the size of a handprint – to bring your car to a halt and ensure it corners properly.
Tyres must cope with potholes, operate in extremes of temperature, provide grip in dry, wet and icy conditions and form a comfortable and quiet buffer between you in your car and the road. They are complex technical items with intricate internal structures and can be damaged if not looked after. Yet owners often bump up and down kerbs, begrudge the cost of tyre replacement and continue to drive when they are worn or damaged. They really do need to be looked after for yours and others’ safety.
Carrying out regular checks
You should check your tyres at least monthly. If you are a high mileage driver, it makes sense to check your tyres fortnightly or even weekly.
Tyre pressures affect the performance of a tyre so it is important all pressures are as per the manufacturer’s guidelines. (These can be found on the back of the fuel filler cap flap, on one of the front door frames or in the handbook.) Pressures should be consistent across each axle (so both front tyres the same as each other, both rear the same). The guides usually show different pressures for driving the car when empty or if fully loaded. Front pressures can often differ from rear ones because a car has different weight considerations with the engine usually over the front wheels.
Under-inflated tyres can increase fuel consumption. Incorrectly inflated tyres will also cause premature wear. Over inflation will wear the centres of the treads; under inflation will wear the outer edges.
While all cars sold in the EU since November 2012 must be fitted with tyre pressure monitoring systems (TPMS), the sensors are notorious for failing so it still makes sense to do a visual check each time you approach your car.
Next, check the tread depth of all the tyres. The minimum in the UK is 1.6mm across the middle three quarters of the tyre width. While you can use a tread depth gauge, it is easy to check this visually: the central groove around a tyre will have small block markers at various points and these are 1.6mm from the base of the tyre. If they become flush with the rest of the tread, then the tyre is worn to its legal minimum. Note this really is a minimum because the tyre’s grip and ability to expel water deteriorate markedly once a tyre has less than 3mm depth. Our recommendation is to replace tyres before they reach 2mm.
As well as the tread depth and pressure, it is important to look for the following:
- Cracking – indicates old and often hardened tyres, affecting both ride and grip
- Deformities – these could mean a fault in manufacture or more likely the tyre has been involved in an impact, perhaps with a pothole or kerb
- Cuts or scuffing – this could lead to failure or hide internal damage
- Damaged wheels – if there is a dent in the wheel rim, it could mean the tyre is damaged internally too, even if there is no visible sign
- Wheel alignment - if your tyres are wearing on the outer or inner edges, it is likely that your car requires its wheel alignment checking and adjusting. This isn’t confined to older cars; it could be the result of an impact.
Don't forget about your spare tyre!
Whether your car carries a full-sized spare tyre or smaller ‘space-saver’, you should check this too. Invariably, they spend their lives beneath the boot floor don’t become worn out but can lose pressure or simply become old. If your car has a repair kit - a can of sealant and a compressor - it’s also important to check these are in good order.
It is important to have the same brand and model of tyre on each axle (and ideally on all four wheels) to ensure consistent performance, especially for braking. After that, there is an element of personal choice. The general rule of ‘you get what you pay for’ holds true with tyres and the more expensive ones usually outperform the cheaper brands. You will need to ensure the tyres conform with the specification of the car too: they should be the right size for the wheels and have the correct load and speed ratings (see below).
Usually cars wear tyres out but age can be an issue for older cars doing low mileages. Remember tyres may have been manufactured some time before they were put on the car too. Modern tyres have a date stamp to indicate age: look for the letters ‘DOT’ and a four digit number showing the week and year of manufacture. So DOT 1017 would mean week 10 (i.e. March) in 2017. Tyres older than 10 years are widely considered unsafe; many manufacturers recommend they are replaced at six years.
To help buyers compare tyres, new ones must be sold with information on wet weather performance, noise and fuel efficiency (otherwise known as energy lost or rolling resistance).
What else should I know about tyres?
When replacing a tyre, you will be asked for its specification so that the new one will be correct for your car. All manufacturers use a standardised set of numbers and letters.
It is written on the sidewall and looks like this:
275/45 R 17 91 W.
The first part relates to the tyre’s size, the second to its performance. Here is what the numbers mean in this example:
- 275 is the width in millimetres
- 45 is the height ratio (in this example the height of the tyre wall is 45% of the width)
- R relates to the type of structure (R for radial)
- 17 is the diameter of the wheel in inches
- 91 is the load rating (in this case maps to 615kg for each tyre)
- W is the speed rating (in this case a maximum of 168mph)
About the Author
Andrew is a freelance motoring journalist with a background in IT and the vehicle leasing industry. With a lifetime’s passion for all things automotive, he can be found behind the wheel of everything from vans to supercars. In addition to reviewing the latest vehicles and technology, Andrew also runs a couple of classic British motors. He lives at the edge of the Peak District with his son and cat.
Andrew Wright @theMotorWriter