Classification Of Tires
Diagonal and Radial Tires
The carcass of diagonal tire consists of a certain number of rubberized cord plies the edges of which are twisted around wire circular bars (they enable the mounting of the tire on a wheel). All threads of the carcass and breaker cord are intersected in adjacent areas. The angle between carcass and breaker cord usually equals 45o – 60o. There are usually four adjacent areas. The design of diagonal tires is outdated but they are still produced (usually for old models of cars) as their production is comparatively cheap. Besides this, their carcass is more resistant to damage in case of strokes or cuts.
Radial tires (R type) all carcass cord threads are situated radially parallel from one bead to the other. The breaker cord threads are placed the same way as in diagonal tires but at a higher angle. Such design makes the carcass not strong enough to endure cornering and acceleration loads. That’s why it has to be supplemented with other tire elements. The carcass is usually reinforced by dual steel belt or is stabilized with nylon band.
Summer And Winter Tires
Summer tires usually have distinguished circumferential grooves that withdraw water from the contact patch, shallow lateral grooves and the absence of micro pattern. Besides this they always have rounded shoulder area.
The tires of such type provide maximum traction on dry and wet surface, high treadwear resistance level and perfectly suit for speedy driving. But they are not intended for off-road conditions (especially when the surface is wet).
Winter tires are used for the operation on ice- and snow-covered surface. The traction performance of such tires may vary depending on the situation, from minimal (smooth ice or slush) to average (snow-covered surface). The tread pattern of such tires has independent tread blocks as well as deep circumferential and lateral grooves. The blocks have special pattern to increase the lateral operating area.
What Are Tires Made From?
The major material for the manufacture of tires is rubber. It can be both natural and synthetic. The synthetic rubber is used more widely as it is cheaper and has properties similar to natural. There are two simple methods by which You can check the quality of the rubber.
First of all You should run Your finger over the tire. If You see a clear mark on Your finger the tire will not serve long as it has too much additives. The next thing You can do is to try to tear off a “whisker”. You will not be able to do so if the tire is of a high quality. Besides the rubber the tires are manufactured from compounds – artificial mixtures of monomers and polymers.
The compound is cheaper than rubber and has a higher quality. The second component is cord. It is a fabric made in form of metal or nylon threads. Rubber-coated threads of cord form carcass. The carcass can be either textile or glass. Both variants are typical for passenger car tires as trucks use tires with metal cord.
Glass fiber provides high resistance to stretching and decay. The tires made with the use of the material have higher treadwear resistance level and, as a result, longer service life. Depending on the layout of the threads the tires can be divided into diagonal and radial. The latter are more rigid and ensure a higher durability.
In such tires the number of carcass layers may be modified what results in the minimization of weight and the decrease of the tire’s heating. It also extends the service life. The breaker is usually situated between the tread and carcass. It protects the latter from the strokes. The breaker is made from the thickened layer of rubber or criss-cross layers of metal cord.
The thick layer of air-proof rubber covers the bead in tubeless tires. It is the element that enables air-proof junction with the bead. So, the frame of each tire is rubber or materials on the base of rubber with other additives. The correlation of materials, density and other features may differ thus determining the quality of a specific tire.
The History Of Winter Tires
The idea to divide tires into summer and winter types appeared in the 1960ies. Initially it was extremely difficult to convince the drivers – at first time it sounded as incredible as if You were offered a set of winter doors for Your vehicle.
But increasing mileage as well as view of cars riding on ice-covered surface made people revise their opinion and purchase wonder tires. It is necessary to point out that fifty years ago the rubber differed from the modern one: it was very porous, soft and didn’t suit for winter tires.
The designers found only one decision: to make huge studs with an inch height and hope that it will help. On ice and snow such tires performed much better than “bald” ones but the steering control at low speeds left much to desire. New technologies were to be adopted.
In the 1970ies chemists offered a new rubber compound that was immediately adopted by the military forces. Tire manufacturers decided to use it for the production of passenger tires. It was the first time when the drivers didn’t have to worry about the traction performance on ice, snow and wet asphalt.
In 1975 the governments of many European countries prohibited the use of stud tires as they spoiled road surface.
The situation was quite interesting: no one wanted to use summer tires in the winter but at the same time it was impossible to produce new models. There appeared such crazy ideas as the use of suction cups on the tires or molding of wire into the tread. Both ideas failed as few years later the chemists offered a new durable and elastic material that resolved the crisis in the tire industry.
In 1982 the Michelin company presented a new model that later became the prototype of all modern treads. In 1999 one could operate winter tires at 150mph (not on ice-covered surface, of course).
Modern winter tires provide due level of safety and comfort and You are not forbidden to operate them in the city conditions.
Check Your Mail! Your Tires Have Worn!
It is not a secret that today in Europe practically every step of the driver is subject to thorough documentation that is conducted with the help of video cameras and different sensors. For example – if You stay at a parking with Your engine turned on a little bit longer, a watchful sensor will immediately report about the exceeding of the maximum amount of the exhaust gas emission in the atmosphere. And You will be fined! The new development of the “ProContour” company is aimed not at the restriction of the driver’s freedom but at the saving of priceless lifes.
A high-speed camera with laser tread control system is will be installed on busy highways to detect the tires with worn sipes. The astonishing performance speed of the system (more than 430mln detections per second) will allow to reach excellent results. Three-dimensional scan of the tread profile and powerful analyzer will allow to detect the type of the tire and whether it conforms to the season. In the future the company hopes to extend the set of functions and teach the system to determine the index of admissible load.
The producer hopes to sell the units to the cities that suffer from accidents occurred due to the use of worn tires. For example, in Germany worn treads entail not less that four accidents every day.
The company guarantees the operating capacity of the unit even at 60mph speed.
But it would be useful to remind – on dry surface the tire can easily “digest” rapid acceleration allowing the vehicle to brake efficiently. But even the slightest change of the driving conditions, light rain and snow will cause immediate skidding. Hydroplaning effect and laws of physics cannot be abandoned.
Good luck!!!
