Truck Tyres: specifications, types

The type of vehicle for which the tyre is intended. Different types of transport differ in weight distribution, control and movement features. Therefore, it is impossible to violate the recommendations for the intended purpose, otherwise you may encounter various troubles - from deterioration in controllability to tyre damage due to off-design loads.

- Trucks and buses. Tyres for trucks of various classes - from light trucks to powerful truck tractors of the "long-range" class. Tyres for buses, trolleybuses and other passenger vehicles are also defined in this category.

— Agricultural and special equipment. Specialized tyres for agricultural, construction machinery and other similar vehicles. Agricultural models are mostly characterized by large sizes and a deep tread pattern - the latter is necessary for efficient work on loose soils and in mud. Tyres for special vehicles often also have advanced "off-road" capabilities, which allows you to effectively move both on hard surfaces and on dirt roads or in mud at construction sites. The speed index for such tyres is usually low - such equipment does not need to be driven fast. There are exceptions to these rules, but they are rare.

The type determines the installation location for which the tyre is designed. Different installation locations require different characteristics, which are taken into account in the design accordingly. It is impossible to violate compliance by type — this leads to off-design loads that increase tyre wear and can even lead to such a dangerous incident as a tyre “explosion”.

— Steering wheel. Tyres designed to be mounted on the steering axle of a truck. At this point, the wheels and tyres are subjected to additional torsional loads along the vertical axis (when the steering wheel is turned from side to side), which puts forward increased requirements for reliability.

— Leading. Tyres designed to be mounted on truck drive axles where good road grip and high resistance to torsional loads on the main axis of rotation are extremely important.

— Trailer. This category includes tyres intended exclusively for installation on trailers (as well as on other axles that are not steering or driving) and not suitable for other uses. With this setup, the torsional loads are relatively low, but the tyre is often subjected to heavy weight loads (for example, in truck tractors, most of the weight is on the trailer).

— Universal. Tyres that allow any of the installation options described above. This option is convenient...because by purchasing a set of tyres of the same model, you can provide them with all the wheels of the truck at once, without buying other tyres. On the other hand, at the same cost, universal tyres are often inferior to specialized ones in terms of performance.

— Steering / trailer. Tyres best suited for either helm or trailer use. See above for more details on each of these options.

The time of year for which the tyre is designed. In fact, we are talking about the regular temperature mode of operation. In truck tyres there are such options:

— All season. Tyres that do not have a pronounced specialization and are suitable for use at any time of the year. Note that the specific resistance to cold and heat can be different, and not every of these models is suitable for driving in severe frost or heat. This point must be clarified according to the manufacturer's documentation. At the same time, this option is convenient in that with all-weather tyres correctly selected for the climate, the owner does not have to “change shoes” for the car when the seasons change. However such tyres in frosty or hot weather will be inferior in performance to specialized winter or summer truck tyres ; however, at less extreme temperatures, this difference is almost imperceptible.

— Winter. Tyres intended for use in the cold season — usually at an average daily air temperature of less than +5 °C (however, specific recommendations from the manufacturer may vary). They are made of softer material than all-weather ones, thanks to which they retain the necessary softness even in severe frosts. In addition, various solutions can be used in the design to improve grip and increase stability on snow or ice. It makes sense to pay attention to such tyres for those...who plan to drive frequently in winter, including in severe frosts: in such conditions, winter tyres definitely outperform all-season tyres in terms of performance.

— Summer. Tyres designed for operation only in the warm season. The standard limit for such rubber is the average daily temperature of at least +5 °C, however, manufacturers may provide other minimum temperatures, so you should carefully read the documents before use. Anyway, in the summer, such tyres are superior in performance to all-season tyres, but this difference becomes noticeable only in hot weather. Therefore, you should pay attention to this option first of all if you plan to intensively operate trucks in the heat — especially since there are very few summer tyres.

Tyre profile width in inches. Inches are the most popular width format; in addition to it, there is also a designation in millimetres. Formally, 1 inch corresponds to 25.4 mm, but in fact the correspondence is not so strict: for example, the width of a 13 ”tyre in millimetres is usually 315 mm, not 330 mm. So it is best to convert millimetres to inches and vice versa using special tables.

As for the width, in this case it is indicated by the distance between the sidewalls of the tyre mounted on the disk and inflated (but not loaded). This is one of the parameters that determine compatibility with a particular disc: the tyre must be slightly wider than the rim. For the selection of rubber for specific disks in width, there are special tables.

Among modern tyres for trucks and buses, there are such standard width options: 6.5", 7", 7.5", 8.25", 8.5", 9", 9.5", 10", 11", 12", 13", 14". Tyres for special equipment and agricultural machinery (see "Intended use") may have larger sizes.

Tyre profile width in millimetres. This designation is noticeably less common than inches (see Width above), but it is also used quite widely.

As for the width in the frame, in this case it is indicated by the distance between the sidewalls of the tyre installed on the disk and inflated (but not loaded). This is one of the parameters that determine compatibility with a particular disc: the tyre must be slightly wider than the rim. For the selection of rubber for specific disks in width, there are special tables.

On the modern market, among the popular sizes, there are such options in width: 205 mm, 215 mm, 225 mm, 235 mm, 245 mm, 265 mm, 275 mm, 285 mm, 295 mm, 305 mm, 315 mm, 385 mm, 425 mm, 435 mm, 445 mm.

Tyre profile height. This indicator determines how much the tyre protrudes above the disk. Specifies the profile height as a percentage of the width (see above). The lower the profile, the better the stability of the car on the road and the faster the rubber wears out; in turn, higher profiles are well suited for rough roads, primers and off-road.

In truck tyres, there are such options for profile height: 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%.

Tyre inner diameter in inches. This parameter determines the possibility of installing the product on a specific car, more precisely, on a rim: the bore diameter must correspond to the diameter of the rim. The dimensions of the disk can be clarified by its marking or according to the documents for the car, in extreme cases, measure it yourself.

For trucks, 17" or less is considered small, over 24" is considered large. The most popular sizes in between include 17.5", 19.5", 20", 22.5" and 24".

The load index characterizes the maximum weight under which the tyre can be safely operated. As in the case of the speed rating described above, this indicator cannot be exceeded, otherwise unpleasant consequences are possible, up to accidents. Also note that when selecting according to the load index, it is worth considering the distribution of weight along different axes of the vehicle. And it is worth considering the maximum possible weight when the truck is loaded, in accordance with what to select truck tyres for heavy loads.

The speed rating describes the maximum speed at which a given tyre can be safely driven. It is worth choosing a model according to this parameter in such a way that during operation it is not allowed to exceed the speed rating — this creates increased loads on the tyre and can lead to its damage (up to an “explosion”). And it is best to choose an option with a margin of at least 10 – 15 km/h — this will give an additional guarantee in case of emergency situations. For truck tyres, speed indices in the range of 100 – 130 km/h are considered popular, and these are the J speed rating(100 km/h), the K speed rating(110 km/h), the L speed rating(120 km/h) and the speed rating M(130 km/h). For agricultural machinery, the speed is much lower: index A6(30 km/h), index A8(40 km/h), index B(50 km/h), index D(65 km/h), index F(80 km/h) ). There are also high-speed truck tyres and less popular speed indices C(60 km/h), E (70 km/h) and G (90 km/h).

Symbol for evaluating the bearing capacity of a tyre carcass. The ply rate indicator does not reflect the actual number of carcass plies in the tyre structure, but indicates the conditional compliance with the bearing capacity in comparison with the reference tyre based on cotton cord. In foreign-made rubber, the ply index is indicated by two numbers and the letters PR (Ply Rating) after them. Models released in the post-Soviet space are labeled similarly, but with a different index - HC (Bearing Capacity). The ply rating in truck tyres shows what maximum load limit the carcass of the rubber product corresponds to. The higher the value of the ply rate, the thicker and stronger the tyre, the greater its load capacity.

- Chamber (TT). In such tyres, it is supposed to use a separate inner chamber as an air reservoir, which is filled with air under pressure. Tube tyres were common earlier, they are now being phased out in favor of tubeless tyres. The main advantage of such models is that a punched pneumatic chamber can be sealed and used further. However, tube tyres add mass to the wheel, and friction between the tube and the tyre causes heat and accelerated tyre wear. In addition, in the event of punctures, chamber models almost instantly lose pressure, which promises a loss of control over the car. Tyres for the pneumatic chamber are usually designated with the TT (Tube Type) marking.

- Tubeless (TL). In tubeless tyres, air is held directly in the space between the wheel rim and the tyre. The sealing cavity is formed by a layer of rubber on the inner ring of the tyre, which has an increased gas tightness. Tubeless models are lighter than their chamber counterparts, which has a positive effect on vehicle handling and reduces fuel consumption. Also, tubeless tyres provide less chance of depressurization in case of punctures - the pressure in them is often systematically and gradually reduced, reducing the risk of loss of control over the machine. Tubeless tyres are marked with the designation TL (TubeLess).

The rolling resistance index that the tire corresponds to. The higher this indicator, the lower the resistance, the less fuel is spent on overcoming it and the more economical the tire is. Efficiency indices are designated by letters of the Latin alphabet in order of decreasing efficiency: from A to G (lowest efficiency).

All other things being equal, more economical tires ( A, B, C, D) tend to cost more, but this difference is offset by fuel economy.

An index that determines the overall performance of a tyre on wet pavement. Lettered from A (highest) to G (lowest).

The higher this indicator, the stronger the tyre “clings” to the wet road, the more efficient and safer it will be in bad weather, all other things being equal. At the same time, it is worth noting that a low grip index does not mean unsuitability for driving in rain or snow - you just need to be more careful on such tyres. Conversely, a high index does not relieve the driver of the need to be careful in difficult weather conditions.

The average noise level generated by a tyre while driving. The lower this indicator, the more comfortable this model will be, the less additional noise it will create.