Checking your tyres… what.. why.. when.. and how…??

WHAT…

So.. How many of you actually know what you’re looking for when you check your tyres? I’ll be the first to admit that before I started working at Merityre I had no idea that the tread on your tyre could wear unevenly, or that you could actually repair a puncture rather than having to buy a brand new tyre. Well in this entry I will try to explain exactly what to look for when you check your tyres.

WHY…

It should go without saying that your tyres are a fundamental part of your vehicle as they are the only parts which have contact with the road (hopefully)!! It is therefore incredibly important that your tyres are in a safe and working condition when driving yourself/friends/family or anyone else around. You never know how many times your tyres may have saved you and your vehicle from serious accidents or damage already.

Did you know that WORN TYRES:

·         Are unsafe

·         Do not give you the adhesion to stay safe on the road

·         Can be illegal… Penalty points here we come

·         Can burst, leading to serious accidents

·         Increase fuel consumption!

·         Pick up foreign objects more easily which can lead to punctures

·         Can lead to other more serious problems with your car

·         Can increase the possibility of prosecution after an accident and increase insurance premiums.

·         Will give you an uncomfortable ride

WHEN…

So firstly, when should you check your tyres? Well there isn’t really a set amount of time between when you should do checks, but we would recommend every week, and before undertaking any long journeys. This means that if you do have any problems, you will spot them quickly and hopefully avoid driving around on potentially dangerous tyres.

HOW…

The first step is to turn on your engine (with the handbrake on and out of gear), and turn the steering wheel so it locks on one side, then turn the engine off again (this will depend if your vehicle has power steering). This allows you to see the full breadth of the tread on your front tyres which is important as it allows you to notice if there is any uneven wear across the tyre.

(Many modern vehicle tyres are very wide and the innermost edge of these can wear right down while the outside edge can appear faultless. This can also occur on tyres if the steering and suspension alignment is out on the vehicle. It is very important to check the full width of the tread!)

LOOK FOR…

·         Now you check your tread depth. The easiest way to do this is using a tread depth gauge, but if you don’t have one of these you can use the tread wear indicators which are located within the grooves of the treaded part of the tyre. These are small raised blocks about 10mm in length and 2mm in height which are situated all around the tyre (so you should be able to find them). The legal limit for tread depth is 1.6mm and the indicators are raised to 1.6mm to 2mm. Therefore if any part of the tread area is running flush with the indicators, your tyre has worn to its lowest level and needs replacing.

 

·         You need to make sure that you check as much of the circumference of the tyre as possible as sometimes one section of the tread will be fine, and another section will be worn. This may mean that the tyre is distorted. You need to check for any material degradation in the tyre, for example cracking and perishing.  At the same time look for any deep or long cuts and any foreign objects. Your car drives over lots of different surfaces so you may see bits of stones here and there, but any object which does not come out easily may have penetrated the tyre and be causing pressure loss (puncture).

 

·         Now have a look at the side walls of the tyres. The side walls are prone to damage from impacts, chafing against curbs, under inflation and tearing. You will be looking for cuts, abrasions or missing rubber. When a tyre has a puncture or has been run under inflated for a while it can cause pinching between the wheel and the road surface (run flat damage). This can be seen as an abrasion mark running the entire circumference and worn letters and numbers on the side walls. When this occurs your tyre will need replacing.

 

·         Bulges can be detected by running the flat of your hand over the entire surface of your sidewall. A bulge represents serious damage to the structural integrity of the tyre.

 

·         In the outer rim of the wheel you will find the valve. Check this carefully for any deterioration of the material. Ensure caps are fitted. By moving the valve stem from side to side, look for cracking of the rubber around the base.

Repeat all of these processes for each tyre and don’t forget the spare!

So, for a quick recap:

Your tyres need attention if they have:

·         Low tread depth

·         Deterioration of the rubber (cracking or perishing)

·         Uneven tread wear (distortion of tyre)

·         Deep cuts or sections of tread missing

·         Embedded foreign objects

·         Side wall damage and bulges

·         Damaged or worn valves

So.. Now you know why it is so important to check your tyres, and not just the tread depth, but the whole tyre. If you find this all a bit too much, then just bring your car to your local Merityre Branch www.merityre.co.uk/find_a_centre.htm and we’ll do it for you absolutely free. We will also give you advice on when you may need new tyres and give you a Merityre Tyre Check Report on their condition. You can also have a FREE Wheel Alignment check which will show up any problems and help to prevent your tyres from wearing unevenly.

For information about our Club Card Plus, go to our website at www.merityre.co.uk or ask at your local branch.

The next entry will explain how to check tyre pressures.

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For Your Tyre Treads' Sake. Wheel Alignment

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.