Merityre Article Archive

Car tyre forensics seems like an odd concept. However, in many instances, a ‘dead’ tyre can give you as much information as a corpse in the hands of a police pathologist. Information? Yes, tell-tale signs that can tell you what caused the tyre’s untimely demise. Such information is useful because in indicating possible faults, it can tell you what might require fixing to give your replacement car tyres or tyre the maximum possible life.

Let’s start with the basics. The type of tyre wear pattern that’s to be expected is straightforward, and is characterised by the tread’s having been worn away to the extent that the tyres’ tread wear indicators are at or near level with the surface of the tread. So, the tyre has nearly finished its useful service life. Is this the end of the story? Not necessarily. The suspension geometry on some cars can mean that the tyres’ treads don’t necessarily wear completely evenly.

Other car tyre tread wear patterns tell a different tale. What must be borne in mind is that they don’t necessarily tell it quickly – some wear conditions take a while to show that something is awry. For example, what does feathering on both outer edges of the tyre tread suggest? This pattern is the most likely indicator that the tyre has been consistently run at too low a pressure. Conversely, a strip worn around the centre of the tread indicates a tyre having been run at too high a pressure.

What about feathering on one edge of the car tyre tread? Should such wear be on the outer edge of the tyre, it suggests that the car’s steering is misaligned, having too much toe-in. Similarly, feathering on the tread’s inner edge indicates that there is too much toe-out. This kind of wear usually appears on both front tyres, as the steering will generally attempt to run straight and true. The fact that the steering tries to compensate for misalignment by effectively evening out the wear on each side of the car is no compensation in itself. However, it does advise you to have the wheel alignment checked before your new tyres suffer.

It’s worth noting that feathering on one side of a car tyre tread occurring only on one side of the car indicates something other than misaligned wheels. In this instance, one-sided feathering is more suggestive of wear in the car’s suspension joints, its springs and/or its wheel bearings. This pattern can also occur when the wheel’s camber, its position in relation to the vertical plane, is incorrect. Camber change of this kind can be caused by wear in the aforementioned areas; damage to the suspension can cause the same problem.

‘Cupping’ is also a phenomenon that can show you something is amiss on your car. A tread with cupping (also called ‘dipping’ or ‘scalloping’) has patches of wear across its tread’s surface. This can look almost like the tread surface has softened in places, or has been scooped away. Cupping indicates one of two problems or a combination of them. Wheels significantly out of balance can suffer cupping, as can car tyres under the control of worn shock absorbers. Cupping can affect rear tyres but it’s more commonly seen on a car’s front tyres.

As you can see, car tyre tread wear can be the result of maladjustment but wear and damage can give similar results. In the interests of your wallet, if not your life, pay attention to what your car tyres are telling you.

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

Car tyres don’t generally ask too much of you. However, neglecting them can prove expensive and, in some circumstances, dangerous. These ten tips will enhance car tyre life, reduce your spending and perhaps save your life.

1. The wrong car tyre pressure is costly. Running on overinflated tyres accelerates wear and reduces both grip and ride comfort. Underinflated tyres also wear more quickly, and can worsen fuel economy by as much as ten percent. Check your tyre pressures regularly.

2. Cuts in car tyres are obvious. Lumps or bulges may be less so but they tend to indicate damage inside the car tyre’s carcass. Check for any such damage while correcting tyre pressures. If in any doubt, avoid the risk of a blowout by having a tyre specialist examine the damage.

3. A spare wheel with a flat tyre is worse than useless. Check the spare tyre pressure regularly, unless you have run flat tyres or an onboard tyre pump and repair kit. Remember that space saver spare tyres generally have speed and distance restrictions.

4. If, at car tyre checking time, you find a stone embedded in a tyre tread, you can lever it out before it causes damage. However, if you find a nail in a tyre, leave it alone. The nail will be temporarily keeping the air in – have a tyre specialist take a look. He may be able to repair the tyre.

5. While using the tyre inflator at a garage, or a tyre pump at home, look after the tyre valve dust caps. They keep dirt and grit away from the delicate valves, and are a line of defence against tyre pressure loss. Always put them back carefully.

6. Potholes can damage more than your car tyres. Hit a large one hard enough and you could be facing a bill for the repair or replacement of one or more wheels. Should you be unlucky enough to encounter a big pothole and suspect damage has occurred, stop and examine the affected wheel(s) and tyre(s).

7. Never straddle a speed bump. Instead, let the wheels on one side of your car pass over the bump. This will prevent damage to your car’s tyres, steering and suspension. When negotiating speed bumps and road-width speed pads, slow down or face the cost of repairs.

8. When you’re manoeuvering, curb your enthusiasm so you don’t kerb your car tyres. Kerb impacts can wreck not only tyres, they can scratch, chip and even dent your car’s wheels. Steering misalignment can also result from kerbing.

9. Keep your car in a garage, if you can. Car tyres suffer from prolonged exposure to ultra violet light. This leads to cracking and crazing of the car tyre sidewalls’ structure.

10. When the time to buy replacement tyres rolls around, think about replacing all four. Should this be too costly, always have new tyres fitted in pairs. It’s accepted that the new tyres should be fitted to the rear wheels.

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

Wheel alignment? Surely your car’s wheels are in line all the time? In fact, they aren’t necessarily. Speed bumps, kerbing, speed pads and general wear and tear on a car’s suspension and steering can put the wheels out of alignment. Misalignment may be felt as pulling to one side or another, and/or strange steering. In the longer term, your car tyres will suffer – bad wheel alignment can radically reduce tyre life.

So, how do you fix poor wheel alignment, thus making your car steer and brake better, as well as achieving maximum car tyre life? The good news is that car manufacturers provide a means of adjusting wheel alignment. The not so bad news is that you can’t correct poor alignment yourself.

Cue a visit to your local friendly tyre man. Good tyre bays (and garages) have the equipment to check and adjust wheel alignment. All you have to do is watch (or not, depending on your preference) and pay for the work. Then, drive away secure in the knowledge that your car is shipshape in the wheel alignment department.

What happens in a wheel alignment session? Generally, three things are checked, and adjusted as necessary. The first check establishes that the car tyres are vertical, as viewed from the front or rear. Sometimes, the tyres may not be truly vertical. Some cars’ tyres sit at a slight angle from the perpendicular. This is the camber angle, which can be adjusted to meet the car maker’s specification.

The second check involves another angle, the castor angle. Does your car run on castors? Technically, yes, the castor angle permits the wheels and tyres to return to straight ahead when the car is rolling with no steering input.  As you know, your front wheels turn from side to side in response to your turning the steering wheel. No matter how the wheels and tyres pivot, a line drawn through the centre of the axis on which they pivot won’t be vertical. The line has to lean backwards slightly and if it doesn’t, the steering will feel very odd. Again, this can be cured by adjustment.

The last check is on a figure called the ‘toe’. All car suspension has a small degree of flexibility built into it. So, if the car tyres are parallel at rest, the drag between them and the road as the car moves would cause this flexibility to allow the wheels to splay very slightly. You wouldn’t see this but your tyres would soon tell you all about it, by wearing out the inner edges of their treads. So, the wheels are usually set to ‘toe-in’, so they run parallel. If the tyres toe out, if the toe-in is too much or if the toe angle varies from side to side, the car tyres will wear out prematurely. Curing this is again a matter of adjustment.

Wheel alignment used to be checked with a special gauge that used a mirror and lens system. Nowadays, it’s common for car tyre bays and garages to measure the angles involved using laser equipment. Yes, accurate measurement is necessary. In some instances, worn suspension or steering components mean that a problem can’t be adjusted away. Then, the tyre man in question will tell you what needs repairing or replacing for accurate alignment to be achieved.  It’s also the case, especially on a car with independent rear suspension, for the rear wheels and tyres to be misaligned. Once again, adjustment is usually possible.

Is it possible to stop your car’s wheels becoming misaligned and making the tyres suffer? In a word, yes. Don’t kerb your car tyres. Avoid potholes and traverse speed pads carefully. Above all, always negotiate speed bumps with the tyres on one side of your car. Straddling speed bumps is a major cause of both wheel misalignment and tyre carcass damage. You have been warned!

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

Last night’s frost warning was a harbinger of the approach of winter. Here in the UK, we should be used to harsh conditions. However, give us an inch (of snow) and the miles aren’t covered…the country tends to come to a grinding halt. Is there a solution? Well, the increasingly popular winter car tyres may help.

This begs a question: are winter tyres genuinely useful or are they just a way of extracting more money from we motorists? Let’s see.

Recommended in Andorra, Italy, Norway and Switzerland, winter tyres are compulsory in Austria, Germany and Sweden and mandatory in Finland. These rules naturally apply on snow-covered roads and/or during the snow season. Often, there is the distinction that the tyres must be marked ‘M&S’ (no, not Marks and Spencer, the marking stands for ‘Mud and Snow’.) Newer snow tyres may have a symbol of a snowflake in front of a mountain. Currently, the distinction between winter and snow tyres is a touch unclear. A good tyre bay will advise you of the exact designation and specification.

In fact, specification is what winter tyres are all about. Car tyres in general are made in much the same way but the rubber compounds used and the tread patterns vary. Winter tyres are made with a high silica content. The probable tread pattern has two tricks up its sleeve. One is a more aggressive tread pattern than ‘summer’ car tyres. This is present to enhance grip.

The winter car tyre tread’s second line of defence involves a winter tyre key word, flexibility. When ordinary tyres have to work in temperatures below 7 degrees centigrade, they stiffen up in the cold conditions. In winter tyres, the compound and tread pattern both improve flexibility.

The benefit of winter tyres is that they give better grip in cold conditions, in rain as well as when snow and ice are about. There are plenty of subjective reports concerning car tyres and most of those concerning winter tyres are favourable. In some cases, cars found to be pretty hopeless in snow are transformed!

Are winter tyres the car tyres for all seasons? Their name offers a huge clue here. Summer tyres will outperform winter ones on dry roads and in reasonable temperatures, and winter tyres, having a softer compound, will naturally wear faster. This suggests following the lead of many continental drivers. They have two sets of tyres, one for winter, one for summer.

This brings us, in turn, to a potentially superior arrangement, which is also popular on the continent and in some cases is a legal requirement. Generally speaking, car tyres can handle most road conditions. However, in the depths of winter, the environment down at road level can be especially harsh. Car tyres may be able to cope with the salt and grit that gives some winter grip but our alloy wheels can suffer. Many popular cars have base models that wear steel wheels. One solution is to have a set of winter tyres on these. A set of steel wheels, with winter tyres, balanced and ready to roll can be fitted when the thermometer starts to plummet. With these ‘winter wheels’ fitted, your car can take on whatever the season has to throw at it, while your pristine summer wheels can live in cool, dark storage, ready for Spring. Bear in mind that suitable wheel nuts/bolts will have to be factored into the equation.

What’s the bottom line? Assuming you need to use your car in the off season, winter car tyres are worth the investment.

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.