Different Types of tyres
Modified On Mar 26, 2015 06:09 PM By Rahul
The Indian subcontinent has bright sunny days most of the year around and summer as such is the safest time of the year for driving. Just for caution, drivers should be careful in areas which gets summer rains as the oil build up can mix with water to make for a slippery surface.
To ensure the tyre's contact with the road remains rigid as much as possible, summer tyres generally have a simple block-shape tread pattern. This helps to ensure optimum grip ensuring the friction between the tyre and the road surface is maximised at all times.
Here the big question that arises is, in a country like India do we really need winter tyres? Or are winter tyres just another gimmick by car and tyre manufacturers to empty our pockets on something that we don’t really need. Well choosing them over are regular summer tyres still remains more of a personal choice but to clarify these are designed to add grip on ice and snow covered roads providing improved breaking performance and control on slippery surfaces. The tread pattern is normally a fine block design with deep wide grooves which provides increased traction and breaking performance on slippery road surfaces. Winter tyres tend to be made with silica included in the rubber, which stops the tyre getting as cold, and this helps it grip to the road, even in freezing conditions. This technology has been greatly improved by the pattern design and the rubber technology used on the tyre.
All Season Tyres
As the name suggests, these tyres are suited for all season use although they may not be the ultimate performer in very dry or wet weather conditions and on ice but can be used majority of the year saving costs of having to change the tyres in line with the changing seasons. Tyre patterns used on all season tyres are more complex than those on the summer tyre and they also have more sipes or small slits on the tread blocks of the tyres. All season tread designs provide good traction and stability and the tread bites the surface to give grip in freezing conditions. Though one must remember that they are not the best suited for very cold and icy conditions for which winter tyres are the best solution.
In an ideal world, drivers would fit winter tyres during the winter months and summer tyres during the rest of the year. This is not always practical, and all season tyres can provide the added grip needed during the winter that a summer tyre would not give.
Wet Weather Tyres
India luckily experiences all four seasons and some part of the country witnesses an exceptionally long rainy season. Infact Kerala gets the first flavours of the south west monsoon in June bringing with it the advent incessant rains continuing for weeks and another spell with the coming in of the Northwest Monsoon in November. Cherrapunji in Meghalaya is credited to be the second wettest place in the world. Therefore in a country like India, it is therefore important that you have tyres which can perform in wet weather. Wet weather tyres, or rain tyres as they are sometimes referred to, are specifically designed to cope well in rain and wet condition. On a wet road stopping distances increase, and this is even more the case with worn tyres. Visibility may also be decreased. The risk of sliding is also considerably increased if it has just rained after a long, dry, hot spell as the dust and oil on the road may make the road slippery. The braking distance on a wet road may be up to three times longer than on a dry road. A good wet weather tyre will rapidly expel the rain along its tread away from the contact area of the road. So please check the depth of your tread regularly. It should be at least 1.6mm deep. The greater the depth, the better the ability to evacuate water.
In India, almost all luxury and premium car manufacturers use these. Performance tyres are designed for sports cars or for people who drive swiftly. These tyres are softer, they grip better and are good for cornering but have a lesser life compared to normal tyres. These tyres grip more at higher speeds and are able to withstand higher temperatures. These tyres are suited for dry conditions as the treads of these tyres doesn’t dissipate water to the extent that normal tyres do. The best example of performance tyres are slicks which are used in racing. The slicks have no tread on them. The contact patch of the tyre with the road is more resulting in better grip. But if these very tyres are used in wet conditions, they won't be able to pump out the water on a wet road . A Formula 1 slick tyre is very soft and will not last beyond 200-300km.
Performance tyres are differentiated by high (usually “H” or higher) speed ratings and low aspect ratio (profile).
All Terrain Tyres
"All Terrain" tyre generally have a straight 50% split between its on and off road performance. The tread blocks are designed with enough width to resist the clogging up of mud. They are also heavily siped to support the wet weather performance. The tyre’s carcass construction is designed in such a way to produce a flat contact patch to ensure even tyre wear. Such tyres generally have a strong traction in off-road conditions, bold tread pattern resists clogging and easily 'self-cleans' and they are apt at providing a comfortable ride quality.
Run Flat Tyres
These are the most popular tyres of the lot and a revolutionary new concept in the tyre industry. Run flat tyres allow the car to continue moving safely, even once the tyre has developed a puncture and will function even when there is zero pressure in the tyre. So if you get a puncture there’s no need for an uncomfortable roadside tyre change – you should be able to safely drive home or to your nearest garage to get your tyre changed. Run flat tyres also reduce the dangers of a potentially dangerous tyre blow out due to their unique construction. Keeping the correct air pressure in your tyres for all types of tyres is the best way to ensure a longer life from your tyres.
These tyres are designed such that they reduce fuel consumption without affecting the tyre or vehicles overall performance.
"Low rolling resistant tyres" are manufactured by adding silica in with the tread compound of the tyre, which in turn will affect the amount of energy a tyre can absorb whilst it is turning. The lower the resistance caused during "rolling", the lower the vehicles fuel consumption will be.
Traditionally, reducing the resistance and thus the fuel consumption has come at the cost of losing tyre grip in wet conditions. However Eco tyres now combat this as the silica technology in the tyre means manufacturers are able to improve both wet grip and the tyres rolling resistance. What's more, according to some estimates, eco tyres can save the average motorist around Rs 5000 a year.
These are designed specifically for four wheel drive vehicles. Luxury cars such as the BMW and Porsche and some 4x4 models now require a performance tyre and these are designed for mostly road use with a slightly softer tread compound.
The 4x4 performance tyres are designed to be used in the same way car performance tyres are used, and will give 4x4 drivers fantastic grip on the road.
Traditionally 4x4s have been used in a variety of terrains, and for this tyre manufacturers have designed all terrain 4x4 tyres, which can be used on both the road, and in mud. All terrain tyres for 4x4 vehicles have advanced with the improved technology found in tyres, and now offer similar breaking distances on the road to standard road tyres.
All terrain tyres are also well known for the distance they can travel before needing replacement, with the harder tread compound used on such tyres making them wear less.
DIFFERENT TYPES OF TYRES:
1) Cross ply or bias ply
Tyres where the fabric cords run from one bead to another at an angle with respect to the center line of the tyre are called cross ply or bias ply tyres
2) Radial tyres
Radial tyres don't have belts that cross over each other like cross ply tyres do. Here, parallel plies radiate from one bead to another. They are softer and offer a more comfortable ride. As the ride is soft the sidewalls are weak and there is no directional stability, and so stiff belts of steel or fabric run around the circumference of the tyre between the plies and the tread.
Tube tyres have an inner tube in between the rim and the tyre. It's this tube which has the air filled in it. When the tyre is punctured, it's the tube which loses air immediately and the tyre goes flat. This tube is doughnut-shaped and made of rubber. It has a valve which protrudes through a hole in the rim. To repair a punctured tube, it has be taken off from the tyre and rim completely. If a nail punctures the tyre tread, then the tube could have multiple punctures as the tube gets deflated and rotates within the tyre
Tubeless tyres work by sealing the spoke well of the rim, either with a specially designed rim and spokes, or with a butyl/plastic strip. The valve is either a separate item sealed with an 'O' ring or part of the rim strip. The tyre is also air tight, this can be done either by adding rubber to the tyre material, or more commonly by coating the inside of the casing with Butyl rubber.
Tubeless tyres deflate slowly rather than suffering from a blow out, which for some drivers improves the safety and reliability of the tyres.
- Marking/Ratings – Low to High profile tyres
The main thing of your concern when choosing a tire is how much grip it has to automobile and the road . High profile tires have a longer contact path between the road and you car, as with low profile tire they have a shorter contact path between the road and your car. How does this and what does this mean for you and your car you are travelling in.
"Low profile" describes an especially short sidewall height, or aspect ratio, on a tire. That's the amount of rubber between the outside edge of the wheel or rim, and the road. Shorter sidewalls provide crisper handling and positive feedback to the steering wheel, but also give a rougher ride because of less cushioning between the rim and the road, which sends each bump and road imperfection directly to the suspension. Many people also like the looks of low-profile tires.
Tyres have a code system etched into their sidewall, which allows you to understand their technical capabilities.
This code provides information on the tyre's construction (e.g. radial), its size, its load-carrying capacity and its speed rating.
For example, the code on a common fitment for Indian cars is: 205/65R15 95H
205 : indicates the nominal section width of the tyre in millimeters (205mm).
65 : indicates its aspect ratio, a comparison of the tyre's section height with its section width (65 indicates the height is 65% of its width).
R : indicates radial ply construction.
15 : indicates the nominal diameter of the wheel rim (15 inches)
95H : is a symbol indicating the maximum load capacity and speed at which the tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted, and with recommended inflation pressures (95 represents a maximum load of 690kg per tyre; H represents a maximum speed of 210km/h).
- How to identify tyre size
When changing your tyres, make sure they're the same as your vehicle's original equipment tyre size. When tyres are not fitted in complete sets of four, we advise that tyre types are not mixed across an axle. If you are still in doubt, consult your tyre dealer for fitment details for your car in some cases the size will be clearly printed on the outside of the tyre as shown in the picture.
The different numbers and letters that make up the size does get quite confusing so lets try putting it into simple terms. The numbers and letter resemble the tyre width, profile, and rim size, load rating and speed rating.
If we run through the example below I will explain what each letter and number resembles.
size: 205/55 R 16 91 V is made up of the following information:
Width:- The width is measured in millimetres, and is measured from end to end of the tyre including the sidewall but excluding any raised lettering or rim protectors. In the size written above and the image the 205 represents the width.
Height / profile:- The aspect ratio is the height of the tyre, in this case the height is 112.75mm so those of you that are good with your maths will know that 55 % of 205 is 112.75mm. Another way to understand this is that the profile / height is basically a percentage of the width of the tyre.
Rim diameter:-The words say it all how wide your rims are is basically the rim size in this case its 16 inch
Load rating:- This is where most people get confused, but help is at hand. The load index is a numerical code that represents the maximum load a tyre can carry. In this scenario the load rating is 91 which means this it has a carrying capacity of 615kg. All tyres do not carry the same load rating so for more information on please visit our load rating section.
Speed rating:-The speed rating of the tyre determines how fast the tyre can travel, in the above example the speed rating is V this means the speed limit is 149mph. In this example the R donates the radial size and is not a speed rating indicator.