Season
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.Width
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.
Width
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.
Aspect ratio
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%.
Load index
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.
Speed rating
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).
Fuel efficiency
The rolling resistance index to which the tire corresponds. 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.
Wet grip
An index that determines the overall performance of a tire on wet asphalt. Identified by letters from
A(highest) to G (lowest).
The higher this indicator, the stronger the tire “clings” to the wet road, the more efficient and safer it will be in bad weather, all other things being equal. It is worth noting that a low clutch index (E, F, G) does not mean that it is unsuitable for driving in rain or snow - you just need to be more careful on such tires. Conversely, a high index (A,
B,
C,
D) does not relieve the driver of the need to be careful in difficult weather conditions.
Noise level
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.
