An informative guide to tyres
AN INFORMATIVE GUIDE TO TYRES
I have put together the following information in order to help fellow members on issues concerning tyres.
SAFETY & TYRE LAW
Current tread depth legislation requires that car tyres must have a minimum of 1.6mm of tread in a continuous band throughout the central ¾ of the tread width and over the whole circumference of the tyre.
However, despite the law, it is universally recognised in the tyre industry that the legal limit is wholly insufficient to protect drivers especially in adverse conditions. Drivers are therefore advised to consider changing their tyres when the tread depth reaches 3mm. (In the real world, once the tread depth reaches 2mm, it is best to change the tyres. This ensures that you do not run the risk of having inadequate tread depth for adverse conditions. Tyres also tend to loose their performance below 2mm of tread depth, affecting grip and braking).
It is important to understand what the law requires in regard to the condition and care of tyres. Regulations govern many aspects of tyre condition of which the following are the principal points:
1. Tyres must be suitable (ie of the correct type and size) for the use to which the vehicle is being put and must be inflated to the vehicle or tyre manufacturers' recommended pressures.
2. Tyres of different types must not be fitted to opposite wheels of the vehicle (for example, radial-ply tyres must not be fitted to a wheel on the same axle as wheels already fitted with cross-ply tyres and vice versa, and a two-axle vehicle with single rear wheels must not have radial ply tyres on the front axle if cross ply tyres are fitted to the rear axle).
3. No tyre must have a break in its fabric or a cut deep enough to reach the body cords. No cut must be more than 25mm or 10 per cent of the tyre's section width in length, whichever is the greater.
There must be no lump, bulge or tear caused by separation or partial fracture of its structure, neither must any portion of the ply or cord structure be exposed.
P 93 mph
Q 99 mph
S 112 mph
H 130 mph
V 149 mph
W 168 mph
Y 186 mph
TREAD WEAR RATINGS
The tread wear grade assigned to a tyre is a comparative rating based on the wear rate of a tyre when tested under controlled conditions on a specified government test course.
For example, a tyre with a tread wear grade of 150 would wear one and a half times as well on the government test course as a tyre with a tread wear grade of 100. The relative performance of tyres depends upon the actual conditions of their use, as a result of which they may depart significantly from the normal ratings due to variations in driving styles, service practices, changes in climate, and differences in road conditions. A control tyre is used which has a tread wear rate of 100 and other tyres are then compared to this.
In conclusion, tread wear ratings are an indication of a tyre tread wear rate, and the higher the tread wear rating, the longer it should take for the tyre to wear down. (Beware of far eastern Budget/Economy tyres with very high tread wear ratings, they will not out last a premium brand tyre with a lower tread wear rating).
TYRE TRACTION RATING
The traction grades from highest to lowest are as follows;
The above tyre traction grades represent the tyres ability to stop on a wet pavement measured under controlled conditions on specified government test surfaces of asphalt and concrete.
TYRE BRANDS – CONSUMER’S GUIDE
With so many different brands other than the main premium brands on the market, consumers have a baffling choice of tyres yet nothing is known about any of the brands. Hopefully the following information will help educate consumers about the various tyre brands on the market, in order for them to be able to make an informed decision about the various brands.
The UK has an influx of tyres from the far east, which is consistently growing as the UK contains the highest number of economy minded motorists in Europe. In addition, wholesalers are always looking for new brands to introduce and represent. Some national chains like ATS and KwikFit has increased demand for private brands that are exclusive to either a wholesaler or retailer. This means that the premium brand manufacturers realise that their premium products can no longer be all things to all men. Their hi-tech development plants as a result are loosing sales as the number of people buying low cost tyres is ever on the increase as price is this consumers main concern. Premium brand manufacturers are trying to address this with multi-brand marketing strategies in order to maintain market share.
Bridgestone and Firestone are the two main brands offered by Bridgestone/Firestone UK. The Bridgestone brand is the most upmarket of the two brands, being targeted in the UK more at the high performance consumer. Firestone is better known by the general public than Bridgestone and now appears to be positioned more as a mid-range brand in terms of price. Firestone has relatively good share of original equipment fitments and performs well in the standard tyre sector. The brand is also well positioned for sale to company car fleets thanks to the brand's competitive pricing.
Other Bridgestone manufactured tyres you might come across are Dayton, the company's economy brand, Europa, a brand created for Firestone's network of wholesale dealers and First Stop, a mid-range brand created specifically for the First Stop network of dealers, all independent dealers affiliated to Bridgestone/Firestone. Bridgestone also has a shareholding in the Turkish tyre manufacturer, Lassa.
Continental's two main brands are Continental and Uniroyal. In addition to this they own the mid-range brand, Semperit and the US manufactured General brand, well known in the 4 x 4 market. In the medium price sector Continental own the Viking and Gislaved brands which are sold specifically through networks of independent tyre dealers on a national basis. In addition to this Continental markets two economy brands, - Barum and Mabor which originate from Continental's factories in the Czech Republic and Portugal respectively.
Following a co-operation agreement with the Japanese manufacturer, Sumitomo Rubber, Goodyear now operates two premium brands in Europe, the house brand - Goodyear and the Dunlop brand. In addition, Goodyear possess five second line products. The Fulda brand originates from the Goodyear factory in Fulda, Germany and is marketed in the UK as an economical alternative primarily in the high performance and 4 x 4 sectors. Kelly, meanwhile is the company's main economy line. In addition there are three out and out budget lines including Lee, which is sold through Goodyear's Hi-Q distribution network and Debica, which originates from a recently acquired factory in Poland. The final brand which should be taken into account is Sava, the Slovenian tyre manufacturer recently acquired by Goodyear. Two further second line brands - India and Pneumant - are controlled by Goodyear as a result of the agreement with Dunlop.
In addition to Europe's leading brand, Michelin, the French manufacturer markets four other car tyre brands. These include the BF Goodrich brand which is the market leader and a premium brand in the 4 x 4 sector. Goodrich car tyres are also sold as an economy line. Also marketed by Michelin is Kleber, a mid-range brand and Riken, best known as an economy high performance tyre and now sold in the UK exclusively by Kwik-Fit. At the extreme budget end of the market, Michelin sell the Kormoran brand, manufactured in Poland by the company's Stomil-Olzstyn subsidiary. In the truck tyre market, Michelin also own the Hungarian brand, Taurus.
Pirelli markets two economy brands in addition to the premium brand, Pirelli, these being Ceat and Courier. The Armstrong brand of 4 x 4 tyres is also owned by Pirelli as is the Metzeler brand of motorcycle tyres.
Despite the multiple branding strategies of the world's largest manufacturers, the majority of the world's tyre brands are still manufactured independently (although many manufacturers operate using technology bought from the leading producers.
For the record, the following brands, well known in the UK, are all manufactured by independent manufacturers: Avon and Cooper (now merged under the name of Cooper-Avon Tyres), Hankook, Kumho, Toyo, Vredestein, Yokohama.
CAUSES OF WORN TYRES
It is important that you care for your tyres as neglect can lead to expensive and serious problems affecting not only the safety of yourself and your passengers but in some cases also the safety of other road users. Besides usual life expectancy wear under correct conditions, more common causes of tyre wear are listed below.
Under Inflation – causes tyres to war on the outer edges of the tread, leaving the central section of the tread showing far less wear.
Over Inflation – causes the central tread area of the tread area being forced into contact with the road causing rapid wear and excess wear on the shoulders of the tyre.
Mis-Alignment – it is good practice to have your wheel alignment/steering geometry check regularly (once every 6 months or earlier). Wheel alignment should be checked and corrected when new tyres have been fitted to prolong the life of the tyres as well as optimise your vehicles handling. Poor or incorrect wheel alignment causes tyres to wear progressively from one side of the inner edges, causing rapid wear (usually a result of too much ‘toe’ in or out). Average charge is about £25.
Camber problems with steering geometry result in sloping wear on the outer edge of the tread on one or more shoulders of a tyre. This can be rectified by the use of hi-tech premium 4 wheel alignment systems (average charge is between £40-70).
Impact Damage – can result from things like aggressive kerb contact as well as poor road surfaces. Some of the common issues associated with impact damage are localised bulging of the sidewall. This is a serious and dangerous defect which is not only an MOT failure but as a result of a damage to the tyres structure, it can fail at any point without warning, causing rapid deflation of a tyre such as a blow out.
Overloading – many people over load their tyres for various reasons. Some people are simply not aware of tyre loads and other fit unsuitable tyres to their vehicle in favour of cheaper prices. Overloading your tyres causes excess deflection and overheating which is going to cause premature wear at best or a sudden tyre failure at worst.
WHAT SHOULD THE FITTING OF A NEW TYRE INCLUDE
- Safe removal of the old tyre without damaging alloy wheel rims and air pressure sensors fitted to some models.
- Tyre outlets should discard your old tyre (some charge between £1-5 for this, but it should be included with the price of a ‘new’ tyre and not be a hidden extra!)
- Inspection of the wheel rim for loose rust or excessive bubbling that could cause a poor seal between the rim and new tyre causing air to leak out. Sanding down to a smooth finish (wire brush/wire wheel may be required) and then a quick coat of tyre bead sealant.
- The fitment of a brand new tyre valve
- The fitment of the new tyre
- A full and ‘accurate’ balance of the wheel prior to fitment to the vehicle.
- Correctly fitted wheel nuts and a check of the torque setting by hand using a torque wrench.
If you look after your tyres, they are likely to last much longer and should you be unfortunate to have a showing signs of a puncture or damage, this will be brought to your attentions and reduce the likelihood of you having an accident. As few quick tips are listed below.
- Check the tyre pressures on a weekly basis.
- Check the condition of the tyre tread and sidewall for foreign objects and damage.
- Avoid harsh acceleration and deceleration.
- Protect your tyres when you wash you car by going over them with a good quality tyre dressing as good quality will contain protective additives to help avoid premature wear due to ageing and cracking.
- Have your steering geometry check regularly.
- Avoid harsh contact with kerbs during parking.
What is Wheel Balancing?
Wheel Balancing is required to be done every time a tyre is removed and fitted to a wheel rim. It is also likely that wheels may need to be re-checked for wheel balancing after periodically if you find that you’re steering wobbles at or above certain speeds.
To balance a wheel, the wheel must be put onto a suitable wheel balancing machine that is correctly suited to the wheel type and is correctly calibrated. All existing balance weight (clip on/stick on) must be removed, prior to the machine checking for the balance. Upon the machine carrying out its spinning of the tyre, the correct weights must be fitted to the wheel and then re-checked on the wheel balance machine until a reading of ‘0’ shows for both sides (unless this is not possible due to damaged wheel rims that cannot be accurately balanced).
Should I Use Tyre Weld?
Tyre Weld is a useful aid to help get you to safety or a more convenient location following a puncture resulting from a small puncture hole if you do not have a suitable spare tyre.
However, do note, that this is a temporary measure and that the tyre once removed from the wheel rim will have to be replaced as repairs to tyres that have tyre weld/slime in them cannot be made. Firstly its impossible to remove all the tyre weld and secondly if re-fitted the internal remains of tyre weld will compromise safety.
Can I Have My Tyre Repaired?
Whilst some motorists may feel hard done by when outlets refuse to repair a tyre, this is most likely to be down to the following points.
- Tyre repairs are covered by BSAU159F:1990
- Repairs are classed either as a minor or major repair.
- Under BSAU159F:1990, limits to the location, size and number of repairs are outlined.
In addition to the above, tyres that are below the legal limit (1.6mm across the central ¾ of the tread throughout the circumference) should not be repaired. This extends to tyres that have structural damage, run flat damage, impact damage, excessive signs of ageing, exposed cords as well as previous and poor repairs.
My Tyre Looses Air But I Can’t See Anything Obvious (Slow Punctures)
If you have a tyre that you need to inflate either every few days or every week or two, its most likely you have an air leak or slow puncture that’s not clearly visible. You can check the tyre either yourself or take it to a tyre centre where they can check for foreign objects such as small nails, pins and blades etc. If a foreign object is not the cause then you have an air leak which can be down to a few reasons.
You may either have a poor seating between the tyre bead and wheel rim, causing a very slow loss of air or you may have a minute pin hole puncture. In addition to this, ageing tyre valves can deteriorate which can go untraced if you don’t have the tyre checked thoroughly by a specialist.
Where Should I Buy My Tyres?
This is down to personal choice, but I would advise consumers to avoid the likes of national chains such as Kwik-Fit, ATS, National etc. National chains rarely have a genuine good offer and usually have hidden charges lurking.
Online retailers can be convenient for some consumers and there is the possibility that you could get a decent deal on fully fitted tyres, but that’s not always the case and you are most likely to have your tyres delivered to a fitting station of your choice and still have to visit a local fitting centre to have them fitted. Prices can sometimes be a lot higher for tyres when purchasing online, so be sure to remember that just because its online, it doesn’t mean it will be the best deal.
I would personally advise consumers to use online retailers to use a guideline, if they see a good offer and take a print out. Visit a couple of local independent fitting centres and ask them for quotes, if their prices are higher, feel free to ask if they can offer a price match, if the online price is cheaper. This also gives you the opportunity to see how they treat their customers as well as how well they do their job. The fitting staff will also take more pride in their work and go the extra mile where necessary without attacking your pocket with hidden charges. In addition, local independents usually offer very keen prices on tyres to start with and they will also appreciate your direct custom.
Which Tyres Should I Buy?
This can be tough as different people want different tyres, so there’s no right or wrong choice as such, but you need to be aware of what you are buying and also realise the fact that different tyres have different characteristics, so when you are looking at high performance tyres coupled with high performance cars, there will be tyres to suit different driving styles and vehicles. However I will emphasise that you should only fit the correct tyres for your vehicle, taking into account speed ratings, load ratings and reinforced sidewall requirements where necessary.
Budget/Economy Brand tyres are generally best avoided as the demand for the ‘cheapest’ budget tyre usually results in retailers having to offer low quality budget tyres in order to compete with regards to price. This means far too many far eastern budget tyres are in circulation and are manufactured to shockingly low standards resulting in manufacturing defects, poor service life and poor grip levels.
However, if you have a vehicle that you just use in general, are not looking for premium quality but want something that will do the job on a budget price then consider budget/economy brands that are manufactured by the premium brand manufacturers such as Debica, Corsa, Kleber and Semperit etc. With these you will avoid the general problems associated with cheap budget tyres.
Those looking for mid range brand tyres to offer more than suitable performance but without heavy price tags are well catered for. The likes of Falken, BF Goodrich, Fulda, Khumo etc will generally not disappoint as they tend offer very good performance coupled with strict and reputable manufacturing to a high standard. In some respects, performance can match that of premium brand tyres.
Premium brand tyres will never be an unwise choice and will offer the most overall quality that you as a driver will feel while driving. As mentioned above, some premium brand tyres will have characteristics that suit some drivers driving styles and some tyres will be better suited to certain types of vehicles. Within the premium brand sector, I would advise consumers to generally look at offerings from Goodyear, Dunlop, Continental and Michelin.
Pressures Quick Guide
Despite people preferring a specific answer, it’s not possible as you really must consult your owner’s manual or the stickers usually located on the inside of the drivers door and fuel filler flap. These days, many cars come with a variety of wheel and tyre size options which do affect tyre pressure recommendations and some cars are much different in size and weight to their slightly older counterparts which also affects tyre pressures that are recommended for your vehicle.
As a general rule of thumb I will list the following (but there are exceptions on many vehicles, intended driving speeds and load capacities, 4WD and RWD specifications etc which will require further adjustment from the listing below).
Small Cars – 26-30 psi
Medium Cars (excl. 4x4) – 30-34 psi
Large Cars (excl. 4x4) – 32-36 psi.
None of us likes a lot of tyre noise, but some tyres can be noisy and this obviously becomes tiring after some times. The road noise generated from a tyre can depends on various aspects of the way a tyre is manufactured, but, as a general rule of thumb, the more tread blocks that a tyre has, the more noise it is likely to generate. Premium brand tyres with lots of tread blocks can be quieter than many others as they have far more money spent during the research, design and development stages.
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