Sports cars, in general, are low slung speed machines with tyres that stick close to the wheel rims. These tyres with such short sidewalls are called low profile tyres.

The shorter and stiffer sidewalls of low profile tyres allow better steering responsiveness and improve a vehicle's handling characteristics. At the same time, sports cars are capable of high speeds which mean they require more grip from the tyres to stay on the road andndash; reason why low profile tyres have wide contact patches by default.

Low profile tyres serve a dual purpose of improving drive dynamics and providing superior grip. This is why these tyres are a common product in the aftermarket modifications sector. Wider and taller wheel rims shod with low profile tyres can be fit onto any car. However, bear in mind that all vehicles come with a 3 percent margin for increasing the size of wheels and tyres fitted to it. Any bigger and it will adversely affect the vehicle's drive dynamics and ride and handling.

Low profile tyres have their drawbacks though -- a wider contact patch means more grip, which also means that the vehicle will require more energy to move forward thereby reducing fuel economy. Low profile tyres with stiffer sidewalls have less air in them resulting in a bumpier ride.

TIP: Low-profile tyres being used on smooth tarmac gives an excellent feel but if venture on Indian highways with very low profile tyres, you're a potential puncture customer with a damaged tyre and the rim.

A car's tyre must coincide with the diameter of its wheels. The specifications are provided on the sidewall of a tyre. For example, 205/45 R16 83V specifies the diameter of the tyre as 16 inches, which is (mentioned after 'R', that signifies the type of tyre construction. The wheel diameter is measured from lip to lip of a tyre, and coincides with the wheel rim size.

The wheel rim size is specified to ensure the best option for ride comfort and drive dynamics. A small rim wheel fitted with a tall sidewall tyre provides a more cushioned ride but will mar handling, as the tall sidewall will cause the car to roll while cornering.

A large diameter wheel fitted with a slim sidewalled tyre (aka low profile tyres) will make for a bumpy ride as the sidewall is unable to absorb the bumps. But such tyres enable fast cornering owing to minimised roll and better steering feedback.

The wheel radius is half the wheel diameter, the distance from the centre of the wheel, the axle, to the outer edge.

Re-treading is a process by which old tyres with worn out treads are given a new lease of life. 'Re-treading' is more affordable and environment-friendly and hence considered a better option over buying a new tyre.

There are two ways to re-tread a tyre. Hot cure, aka mould cure, involves covering the tyre with uncured rubber and curing it in a mould similar to that on a new tyre. Cold cure aka pre-cure involves applying a pre-cured strip of tread to the bald patch after which the tyre is placed in a under a vacuum rubber envelope and cured in a heating chamber or autoclave, which integrates the new tread on the bald patch. A tyre can be re-treaded several times.

The US and Europe have legislations for re-treading tyres in the interests of foolproof safety.

In India, it is advisable to get tyres re-treaded from an established workshop as sub-standard jobs could mean the re-treaded tyre may burst, crack or the tread may peel off under heavy load or at high speed. Hence, re-treading of passenger car tyres is not recommended. Drivers in India do not adhere to stipulated road speeds.

When the treads on a car's tyres are worn, it's time for a new set of tyres. Follow the car manufacturer's recommendations while selecting the new tyres. If your vehicle has a 'V' tyre speed rating, it is capable of handling speeds of 240km/h, while a 'U' speed rating specifies maximum speed of 200km/h. So you need tyres that match you car's performance.

Tyres are constructed with different treads, amounts of rubber, reinforced fabric or steel cords according to the performance parameters. Naturally, exceeding the tyre's speed limit will put you and your car in hazardous straits, owing to the possibility of bursting or the tread peeling off. Drive according to the speed rating of you car's tyres.

Ascertain the top speed of your vehicle from the manufacturer's manual or test reports in auto journals before selecting the tyres. Tyres with a speed rating higher than that of your vehicle's top speed are the safe bet.

Here is a tyre speed rating chart to help you choose the perfect set of tyres:

The term radial signifies the type of tyre that features a radially arranged set of plies. The cord plies extend from lip to lip of the tyre at a 90-degree angle in relation to the direction of travel. This lowers the rolling resistance of the tyres and increases fuel economy compared to cross ply tyres. The radially arranged plies act like springs and absorb bumps to ensure a comfortable ride. The sidewalls are not as rigid as that of a cross ply tyre, which is why it sags slightly at the contact patch with the ground. Stabiliser belts beneath the tread along the direction of travel add strength to the tyre. These belts are made of steel (hence the term steel belted), polyester, twaron or kevlar to reinforce the tread region and optimise performance, fuel economy and steering response.

Run flat tyres are designed to minimize loss of handling of a vehicle after a tyre puncture has occurred. It allows the car to be driven on the punctured tyre so that the driver does not have to change the tyre. However, after a puncture has occurred it can be driven only for a short distance (about 150 kms) and under a limited speed (usually 80 km/h).

Run flat tyres offer a very bumpy ride and cause the car to feel even minor jerks and bumps on the road because of insufficient air that could have absorbed bumps. Alongside, the sidewalls become rigid and are unable to maintain the shape of the tyre in the event of a puncture.

Run flat tyres have reinforced sidewalls and additional lateral strengthening to ensure that the tyre maintains its shape and form without air pressure in it to bear the weight of the vehicle. Loss of air pressure in a tyre also increases friction and heats up the tyre, as a result heat resistant rubber is used to construct a run flat tyre to reduce heat build up in case of a puncture.

On normal pneumatic tyres, the air pressure inside the tyre keeps the tyre beads in place on wheel rim flange. Run flat tyres are designed to keep the tyre beads in place on the wheel rim flange even while there is no air pressure inside the tyre. This is done by physically blocking off the wheel rim well with a supporting rim (between the tyre and the wheel rim) to support a deflated tyre on the wheel rim. This system ensures that the run flat tyre's beads do not come off the wheel rim flange while the car is moving in a straight line or while cornering.

Vehicles equipped with run flat tyres come with a Tyre Pressure Monitoring System (TPMS) to inform the driver about the vehicle's tyre pressure on each wheel. Run flat tyres are designed to minimise the difference in ride and handling when the tyre is punctured, as a result the driver may not otherwise be aware of a tyre puncture.

Many high-end car manufacturers offer run flat tyres as standard on their cars to save space of a tyre in the boot of a car and improve the convenience of having to change the wheel of a car in case of a tyre puncture.

TIP: Run flat technology tyres on roads which have tabletop surfaces may be practical. Advantages like cornering ability and handling may be enhanced. In a country like India, where highways are riddled with potholes, which sometimes have razor-edges can leave you minus the tyre and the rim. Under such circumstances, if you further do not have a spare wheel which means you take a lift in the next available jaunty jalopy to take you to a place where you can get alternative transport to go home and send a platform for your high-end car to civilisation. This episode can drain your money purse by few tens of thousands of rupees. RUN FLAT TECHNOLOGY TYRES ON INDIAN ROADS ARE A BIG NO-NO

Tyres are constructed with a purpose designed to suit a particular vehicle type. This is done to help the vehicle go about its purpose with ease, bearing in mind the cost constraints of consumers.

For example, a truck is recommended to be fitted with tyres that have a high load bearing capacity, while the speed rating is kept low as trucks are not meant to travel at very high speeds. If both high speed and high load carrying capacity is to be incorporated in truck tyres, it will make them unnecessarily expensive.

Similarly, while technology may exist for companies to manufacture tyres with a speed rating of 300+ km/h, if these tyres are fit to an ordinary hatchback it would be of little use as the car would be incapable of travelling at such high speeds. Also, the cost of the vehicle would go up due to the expensive tyres. As a result, a vehicle is fitted with tyres that have a speed rating slightly higher than what the vehicle can achieve.

High speed tyres are recommended by vehicle manufactures on cars that can exceed a speed of 210 km/h. Cars under this category can range from hot hatchbacks to sports sedans, sports coupes, sports cars and hyper cars.

Here is a chart denoting tyre speed ratings:

High speed tyres are made up of more durable and expensive materials and compounds that can resist high temperatures due to high-speed rolling resistance and deal with strong G forces under hard cornering.

It is obvious that a soft rubber tyre should give you a more comfortable ride than a hard rubbered tyre. But comfort is not only because of the soft rubber, it is also because of the suspension and shock absorption that's matched to it. Moreover, the aspect ratio of the tyre also has a role in the comfort vis-a-vis handling. Aspect ratio is the ratio of tread width to the wall height of the tyre, i.e, if you have a 200mm tread width, the wall height is 120mm for 60 ratio.

As the ratio goes down to 50,45, 35, etc, the the tyre looses its flexibility and the comfort suffers. For example, the Mercedes Benz S-Class rides on tyres that have an aspect ratio of 55 while a Ferrari 458 Italia rides on tyres that have an aspect ratio of 35. This means that the S-Class' tyres have a taller sidewall than Ferrari's. As a result, the S-Class will offer a more comfortable ride while the Ferrari will be able to carry more speed around corners thanks to tyres with a shorter sidewall.

Comfort is always a trade off for handling. Hence, very comfortable cars don't use low aspect ratios. The tread pattern also determines road noise and road grip. It also determines the rate at which water is dispensable on wet roads.

In general, comfort tyres are soft with high aspect ratio coupled to a good suspension.

As the name suggests tube-type tyres consist of a tube which is placed between the tyre and the wheel rim. The tube inside the tyre is filled with air and inflated to allow tyres to support a vehicle's weight and maintain the shape of a tyre.

Tube-type tyres were used for many years by all types of vehicles with pneumatic tyres before the tubeless tyre was created. However, various drawbacks of a tube inside a tyre caused the tubeless tyre to become preferred over the tube-type tyre.

The tubeless tyre scores over the tube-type tyre because it weighs less and hence less unsprung weight. Handling characteristics are also better with tubeless tyres. When the tube-type tyre looses its inflation, it has a tendency to come off the rim causing instability.

The tubeless tyre also has the advantage of repairing punctures without removing the tyre from the rim and this means individuals can repair tyres by themselves if they carry a puncture repair kit in the car. Make sure that the puncture repair is done only to the tread area and not the sidewalls.

Increased environmental pressures have caused automobiles to evolve and become cleaner and more efficient. Apart from modern engine technologies that make vehicles more fuel efficient and emit lower emissions, it has been discovered that tyres, too, contribute to reducing fuel consumption and emissions.

Tyres created to reduce fuel consumption have low rolling resistance. Low rolling resistance, as the name suggests, is achieved by reducing friction between the tyre and the road surface. However, low-rolling resistance tyres adversely affect the tyre's ability to grip the road due to less friction, making it more susceptible to loss of traction and skidding. As a result, in earlier times, it was impossible to make a tyre that reduced fuel consumption and provided good grip on all types of road surfaces and in the rain.

The introduction of silica to a tyre compound has allowed tyre makers to make low-rolling resistance tyres with adequate grip. Tyre experts looked at design, contour, compound and tread pattern, and took a completely new approach to all four components of the tyre to achieve both fuel efficiency and optimum grip.

The optimised tread grooves with extra thin sipes reduce tread deformation and minimise energy loss, reducing rolling resistance. Polymer chains used inside the tyre form a stronger bond with the silica compound. The more rigid structure along with a flatter contour reduces movement of the belt structure inside the tyre. Also, the distribution of tread depth on the tyre tread is altered to adapt to the further reducing movement of the belt structure, thereby lowering rolling resistance.

While eco tyres deliver low-rolling resistance thereby improving fuel economy, these tyres cannot be used on high-performance cars as they do not provide adequate grip. A new type of tyre called the Eco-performance tyre is gradually evolving to bridge the gap between low-rolling resistance and optimal grip.

Eco-performance tyres are made up of compounds that allow it to absorb low levels of energy under normal circumstances to improve fuel efficiency. However, the mixture of compounds used in eco-performance tyres allow the tyre to absorb higher levels of energy at higher frequencies allowing the tyre to have more grip on wet roads, under high speed manoeuvres and under braking.

Eco-performance tyres do not heat up as quickly as regular road tyres thus reducing energy consumption and increasing efficiency of the powertrain. However, the rubber in the contact patch with the road heats up quickly upon braking, shortening the braking distance of vehicles.

Ever had that sinking feeling when driving on a snow-covered road? That's because your car is most likely shod with normal road tyres that are designed for optimum traction on dry and wet road conditions, but not on snow. Regular road tyres are also built to reduce rolling resistance so as to decrease fuel consumption.

Snow tyres, on the other hand, are constructed using a higher percentage of natural rubber and silica as it prevents the tyre from hardening as much as synthetic tyres in cold temperatures, thereby providing better traction.

Tyres with a wide contact patch will make the car sink into the snow. As a result, snow tyres have a narrow contact patch that helps provide adequate traction. Snow tyres also have more sipes on the tread pattern to allow more water to escape from under the tyre and reduce the risk of.

There is also a kind of snow tyres available on the market that come with tiny metal studs in the tread for increased grip on loose or fresh snow. On the flip side, these tyres cannot be used on normal road surfaces as they will wear out quickly. Besides, they would also increase fuel consumption and damage tarmac roads.

Near about all cars sold in the market today are shod with all-weather road tyres. These tyres are designed to perform under varying road conditions and temperatures. The problem here lies with the saying, 'master of all, jack of none.' All-weather tyres are capable of performing in standard road conditions but in extreme road conditions you may have to consider installing specially designed tyres.

During monsoons, water often collects in dips and crests on the road. When a vehicle drives over, it causes a tyre's tread to be submerged in water. A normal tyre's tread will not be able to disperse the water underneath leading to loss of contact with the road, causing the vehicle to spin out of control at high speeds.

If you drive often in rainy conditions, the vehicle should be equipped with wet weather tyres. The tread on wet weather tyres have deep grooves designed to disperse the water from underneath the tyre to provide maximum grip under wet road conditions. These grooves are designed to generate heat when lateral forces are applied, allowing wet weather tyres to grip better. Wet weather tyres are made of softer rubber that allow the tyre to heat up quickly, which helps the tyres generate more traction.

You may be wondering why wet weather tyres are not standard fitment on cars. Wet weather tyres offer superior grip that creates more friction under dry road conditions. This leads to reduced fuel economy and a vehicle's ride and handling dynamics will be altered as suspension setups on standard cars are designed to work well with all-weather tyres.

All-terrain (A/T) tyres are radials usually found on SUVs and trucks that frequently drive on varying surfaces such as tarmac, dirt roads, sand, mud, rivers, rocky terrain, etc. Like off-road tyres A/T tyres have chunky lugs on the tyre tread, however, the lugs are tighter than that of off-road tyres. The chunky lugs on the tyre tread make it easier for the tyres to find traction on loose surfaces while smaller gaps between the lugs on the tyre tread reduce rolling noise on tarmac.

The tread on all-terrain tyres makes it easier to steer the vehicle over varying surfaces due to higher levels of grip. It should be kept in mind that all four wheels of a vehicle should be equipped with one type of tyre, be it A/T tyres or standard road tyres. Different types of tyres on different wheels will provide varying levels of traction which is dangerous in case of high speed driving, especially on slippery or loose road surfaces such as wet tarmac, mud, gravel, etc.

All-terrain tyres are made up of harder rubber which is why they are more durable than standard road tyres in comparison. The sidewalls of these tyres are reinforced to withstand impact from sharp rocks and other obstacles that can be encountered on cross country trails.

The downside of using all-terrain tyres on tarmac is the increased rolling noise as compared to standard road tyres. All-terrain tyres are also more expensive. However, they last longer than regular ones as they are made of harder rubber.

All-terrain tyres are usually fitted to SUVs that are meant for off-roading as well as for on-road use. For example, the Force One is equipped with Apollo Hawkz A/T tyres. Any vehicle can be equipped with all-terrain tyres if it is frequently used for cross country runs, provided the availability of A/T tyres in a particular size.

It is recommended that cars be equipped with all-terrain tyres if the owners frequently do cross country drives, keeping in view safety and longer tyre life.

Tyres designed for increasing grip and handling traits of a vehicle are called performance or summer tyres. Made of soft compound rubber, they are designed to give maximum grip at high speeds during dry weather conditions. Most sports cars are fit with performance tyres to improve their handling and cornering ability. These tyres are also available from the aftermarket for drivers who want better handling and performance from their tyres.

Performance tyres have a low aspect ratio, which means that they have a very short sidewall. A shorter sidewall causes the tyre to have less air in it. As a result, such tyres roll very less around corners thereby improving handling. On the flip side, lesser air makes the tyre stiffer, resulting in a bumpy ride. Also, the soft compound on these tyres leads to such tyres wearing out faster. Since the grooves on these tyres are less, they don't work too well in the rain as the dispersion of water from under the tyres is less. Hence, these tyres run for a long time in places with warmer climes and scanty rainfall.

It's important to constantly check these tyres for wear as they offer little or no grip on wet roads once worn out. An extreme example of such tyres in use is in motorsport, where they are called 'slicks' as they have no tread on the contact patch of the tyres to ensure that all of the rubber makes contact with the road surface.

Cross ply or bias construction is a method of constructing tyres in which a series of cords or plies criss-cross over each other to form a carcass or frame over which rubber is integrated to create a tyre that bears the load of the vehicle. This type of tyre construction was used prior to the radial construction technique of tyres. Cross ply or bias tyres increased friction when the vehicle moved as the plies rubbed against each other, leading to an adverse reduction in fuel economy. Also, the rigid sidewall of a cross ply tyre caused a bumpy ride as it absorbed very little road imperfections and the tyre would overheat at higher speeds (above 80 km/h), which limited the speed of vehicles.

Cross ply tyres have stiff sidewalls due to which the sidewall adjacent to the contact patch of the tyre bulges out very little even though the weight of the vehicle is resting on that area of the tyre. In case of radial tyres the bulge on the sidewall of a tyre near the contact patch can be noticed easily. This is a way to distinguish cross ply tyres from radial tyres.

Tyres constructed using cross plies are more affordable due to the relatively inexpensive technique. Also, they wear out faster due to higher operating temperatures of cross ply tyres owing to a stiff sidewall. Therefore, the cost of owning a cross ply or bias tyres is higher as in the long run you'd end up spending more on tyres than you would with a set of radial tyres.

Cars like the Maruti Suzuki 800, Gypsy, Van, Hindustan Motors Ambassador came with cross ply tyres when they were launched. However, all of them nowadays are equipped with radial tyres.

Tyre bead is a strong and ductile copper/bronze-coated wire covered with rigid rubber that holds a tyre in place on the wheel rim of a vehicle. It is located on the lower most section (in contact with the wheel rim) of a tyre's sidewall and is tightly sealed to disallow any passage from the inside to the outside. This ensures that the tyre is held in place and not allowed to come off the rim under any circumstance.

In case, the tyre has to be removed from the rim, such as while repairing a puncture, a bead breaker can be used to break the bead to remove the tyre from the rim. While the term may sound like the tyre bead is broken, in reality it is just involves removal of the tyre bead from the groove on the wheel rim. Afterwards, the same tyre can be refitted onto the wheel rim as it hasn't suffered any damage while removing a tyre from the rim.

Over the years, better quality tyres have reduced the possibility of a flat tyre though they aren't entirely avoidable. It is best to be prepared against such eventualities to avoid the hassle of changing tyres.

In the case of tubeless tyres, one can use puncture repair kits that come with the tyres or can be bought off the shelves from any tyre shop. These kits usually comprise a spiral tool, an inserting tool, a strip of puncture seals, a tube of rubber cement and a sharp blade. Some kits also have additional tools such as compressed air canisters with covers, valve adapter, etc. Besides, it will be a good idea to buy an electronic tyre inflator.

Here's a step-by-step guide to repairing a punctured tubeless tyre.

1. Inflate the tyre and locate the puncture by checking for any sharp objects like nails or glass shards.

2. Remove the foreign object and any other things that may be sticking out of the tyre.

3. Take the spiral tool and drive it into the puncture in a clockwise manner. This will make it easier to insert the puncture strip.

4. Remove a puncture seal from the strip, feed it through the inserting tool like a needle and thread.

5. Once the seal strip is equal on both sides of the inserting tool, take the tube of rubber cement and apply it to the centre of the seal strip. The inserting tool has a little gap at the bottom that will allow the seal strip to be left behind inside the tyre.

6. Remove the spiral tool from the tyre and insert the inserting tool with the seal strip. The inserting tool will not go all the way in. It will stop after the plastic bit of the handle touches the tyre after which it can be pulled out. At this point, the seal strip will be left inside the tyre blocking the hole in the tyre.

7. The sharp blade should then be used to cut off the ends of the seal strip sticking out of the tyre for an even contact patch for the tyre.

8. Set the appropriate tyre pressure on the tyre inflator and inflate the tyre.

The tyre is now repaired with the vehicle ready to be driven but do get the tyre checked up at a repair shop.

NOTE: ALL PUNCTURE REPAIR SHOULD BE RESTRICTED TO THE TREAD AREA ONLY AND NEVER EVER ON THE SIDEWALL.

Tyre tread is the tread pattern along the circumference of a tyre that makes contact with the road. Different tyres have different types of tread patterns depending on the. The tread of a tyre can be defined by two terms, namely, tyre groove and tyre sipe.

Tyre groove is the sunken pattern of a tyre that does not make contact with the road. Grooves are fundamental in deciding a tyre's quality and improve the braking and handling traits of a tyre. Groove depth and design affects road noise and the rate of the tyre's treadwear.

Tyre sipe is the final groove pattern in the tread of a tyre. The sipes are narrower than tyre grooves and not as deep as the grooves. The function of tyre sipes is to enhance braking, performance, driving stability, comfort and improve braking and handling on wet roads.

The aspect ratio of a tyre is represented by a percentage that indicates the height of the tyre, from bead to tread, in relation to the width of the tyre. For example, if the aspect ratio is 45 then it means that the height of the sidewall of a tyre is 45 percent of its width in measurement. Eg; 205/45 R16 83 V, in this case the aspect ratio of the tyre is 45 percent.

The higher the aspect ratio of a tyre, the taller the sidewall of a tyre will be. Heavy vehicles such as such as luxury cars, buses and trucks have tyres with aspect ratios as high as 95. Tyres with high aspect ratio may compromise on handling but provide a more comfortable ride by cushioning bumps due to more air in the tyre.

On the other hand, high performance cars have tyres with a low aspect ratio. That means that these are low profile tyres with shorter and stiffer tyre walls that allow the tyre to resist cornering forces better, thereby improving handling traits of a car by reducing roll around corners. However, tyres with low aspect ratio compromise on the ride comfort of a vehicle as more vibrations are passed on from the tyre to the suspension of the vehicle. This happens as there is less air in the tyre to absorb bumps and vibrations.

Most regular road tyres strike a balance between high and low aspect ratio to provide good handling traits for a vehicle while maintaining a comfortable ride.

The contact patch of a tyre is the rubber on the tyre tread that touches the road surface. The contact patch of the tyre is the only physical connection between a vehicle and the road surface. The size of a tyre, its tread pattern and the pressure pattern on the contact patch of a tyre determines to a significant extent how a vehicle rides, handles and brakes under different situations.

Different types of tyres have different contact patches depending on the purpose of a tyre. For example, snow tyres are narrow in width with deep groves to dig into the snow for adequate traction without allowing the vehicle to sink into the snow, as opposed to slick tyres used in racing cars on dry roads. Slick tyres have a wide contact patch with no grooves or sipes. This alloys the entire tyre to be in contact with the road for enhanced traction that allows a vehicle to carry more speed especially around corners.

Pneumatic tyres, short for rubber tyres inflated with air, are flexible in nature and hence the contact patch of such tyres differ under different load conditions and tyre pressures. The contact patch of a tyre also varies when a vehicle is stationary and when it is moving. Statistically, a heavier load on the tyre results in a larger contact patch, while more inflation results in a narrower contact patch.

As you may have noticed, tyres of an overloaded vehicle or those with less air cause the tyre to bulge at the bottom over the part that is in contact with the ground. This indicates greater pressure being exerted from the contact patch to the sidewall at that point instead of a more even spread over the entire sidewall of the tyre. This has negative effects on the ride and handling and fuel economy of a vehicle, not to mention the added wear on the tyre.

An over inflated tyre will have to take added pressure on the specific pressure points of the contact patch of the tyre with less pressure going to other areas of the contact patch. This will result in certain loss of traction from the contact patch of the tyre leading to less control over the vehicle, not to mention added strain on the rubber of the tyre causing it to expand. An over inflated tyre will allow more vibrations to pass from the road surface to the suspension of a car resulting in a bumpier ride and the suspension will have to work harder to cope with the vibrations.

It is, therefore, crucial to maintain the correct tyre pressure recommended by the car manufacturer for a safe, comfortable and enjoyable drive.