Suitable for
This parameter is indicated for models that are designed for a specific format of operation and differ markedly from conventional tyres for "everyday" use. In our time, there are such destinations:
sports track tyres(namely, semi-slicks and slicks for track days and training on race tracks); off-road tyres - all-
terrain (All-Terrain) and
off-road (Mud-Terrain). Here is a detailed description of each of these options:
— Sports track. A special kind of "high-speed" tyres with a reduced tread depth. More precisely, this feature is characteristic of semi-slicks; in slicks, there is no pattern at all, the surface of such a tyre is completely smooth. This provides excellent speed performance. On the other hand, slicks and semi-slicks are intended mainly for specialized racing tracks with high quality even surfaces; the use of such tyres on ordinary roads is at least not recommended, and for some models it is completely prohibited.
- All-terrain (All-Terrain). Universal all-terrain tyres, designed mainly for dirt roads and off-road, but quite effective on even asphalt. They are inferior to off-road ones (see below) in terms of efficiency on rough terrain, but they behave better on hard surfaces. So it is precisely such rubber that will be the best choice for tech who, in addition to difficult terrain, often have to travel on ordinary roads. Externally, tyres o
...f this purpose are characterized primarily by a rather deep tread and high profile.
- Off-road (Mud-Terrain). Tyres designed for maximum cross-country ability and efficiency on rough terrain, including complete off-road. According to these indicators, such tyres are noticeably superior to all-terrain tyres (see above); outwardly, it is distinguished by a very deep tread and a high profile height (in most models - 60% and above). But for regular driving on asphalt, tyres of this purpose are poorly suited. Therefore, paying attention to off-road tyres makes sense, first of all, to tech who have to drive on dirt roads and off-road most of the time.Width
Tire section width is the distance between the sidewalls of an inflated but not loaded tire. As a rule, this parameter is indicated in millimeters, but there are also inch designations for the profile width.
Width is one of the characteristics that determines the compatibility of a tire with a specific wheel (the second characteristic is the mounting size). It is worth noting that the width of the tire does not have to strictly correspond to the width of the rim; certain deviations are allowed. There are special tables that allow you to determine the permissible width values for a particular wheel; in addition, such recommendations may be indicated in the documentation for a specific car.
The following tire width options are available on the modern market:
135 mm,
145 mm,
155 mm,
165 mm,
175 mm,
185 mm,
195 mm,
205 mm,
215 mm(in inches this is
8.5”),
225 mm,
235 mm,
240 mm(in inches this is
9.5”),
245 mm,
255 mm,
265 mm(in inches this is
10.5”),
275 mm,
285 mm,
290 mm(in inches this is
11.5”),
295 mm,
305 mm,
315 mm,
320 mm(in inches this is
12.5”),
325 mm,
335 mm,
345 mm(in inches this is
13.5”) and
over 345 mm(
over 13.5”).
Aspect ratio
Tyre aspect ratio. This parameter is usually expressed as a percentage of the width, since it is not the height itself that is of practical importance, but its ratio with the nominal section width.
In general, the lower the ratio, the more stable the tyre, the better it is suitable for high-speed driving on flat roads. Higher ratio, in turn, work better on rough surfaces and over obstacles, making them good for bad roads and
off-road. If we talk about specific numbers, nowadays, the following options are spread on the market:
— Low profile tyres:
25%,
30%,
35%,
40% ;
— Medium profile :
45%,
50%,
55%,
60% ;
— High profile :
65%,
70%,
75%,
80%,
82%,
85%, and
90% or more.
Load index
The maximum weight load that the tyre is able to carry. It is denoted by a conditional figure, each of which corresponds to a certain value:
66 - 300 kg, 67 - 307 kg, 68 - 315 kg, 69 - 325 kg, 70 - 335 kg, 71 - 345 kg, 72 - 355 kg, 73 - 365 kg, 74 - 375 kg, 75 - 387 kg, 76 - 400 kg, 77 - 412 kg, 78 - 425 kg, 79 - 437 kg, 80 - 450 kg, 81 - 462 kg, 82 - 475 kg, 83 - 487 kg, 84 - 500 kg, 85 - 515 kg, 86 - 530 kg, 87 - 545 kg, 88 - 560 kg, 89 - 580 kg, 90 - 600 kg, 91 - 615 kg, 92 - 630 kg, 93 - 650 kg, 94 - 670 kg, 95 - 690 kg, 96 - 710 kg, 97 - 730 kg, 98 - 750 kg, 99 - 775 kg, 100 - 800 kg, 101 - 825 kg, 102 - 850 kg, 103 - 875 kg, 104 - 900 kg, 105 - 925 kg, 106 - 950 kg, 107 - 975 kg, 108 - 1000 kg, 109 - 1030 kg, 110 - 1060 kg, 111 - 1090 kg, 112 - 1120 kg, 113 - 1150 kg, 114 - 1180 kg, 115 - 1215 kg, 116 - 1250 kg, 117 - 1285 kg, 118 - 1320 kg, 119 - 1360 kg, 120 - 1400 kg, 121 - 1450 kg, 122 - 1500 kg, 123 - 1550 kg, 124 - 1600 kg, 125 - 1650 kg, 126 - 1700 kg, 127 - 1750 kg, 128 - 1800 kg, 129 - 1850 kg, 130 - 1900 kg, 131 - 1950 kg, 133 - 2060 kg.
While choosing according to this indicator, it is worth considering not only the maximum weight of the car for which tyres are going to buy, but also the distribution of weight along the axles. With passenger cars, everything is simple — the weight is distributed approximately equally, so to determine the load on each wheel, it is enough to divide the maximum mass of the car by 4 (the number of wheels). H...owever, in minibuses, light trucks and SUVs, the situation is different: the weight distribution can be unequal, so you should refer to the manufacturer's documents or other special sources to calculate the load on each wheel.
Anyway, the load index must not be exceeded — this creates the danger of an accident. In fact, the wheel load should be at least 10 – 15% below the maximum, this will give an additional guarantee in case of abnormal loads. Also note that in some high-speed tyres, with the speed maximum approaching, the permissible load decreases: for example, for tyres with the V index (see "Speed rating") with speed over 210 km/h, it is recommended to reduce the load by 3% for every next 10 km/h increase in speed, similar recommendations apply to models with indexes W and Y. These details are usually described in the manufacturer's documentation and other special sources.
Speed rating
The speed rating that the tyre corresponds to.
This indicator determines the maximum speed that tyre is allowed to operate. It is designated by the letters of the Latin alphabet, each of which corresponds to a certain speed limit:
F — 80 km/h; G — 90 km/h; J — 100 km/h; K — 110 km/h; L — 120 km/h; M — 130 km/h; N — 140 km/h; P —
150 km/h ; Q —
160 km/h ; R —
170 km/h ; S —
180 km/h ; T —
190 km/h ; U —
200 km/h ; H —
210 km/h ; V —
240 km/h ; W —
270 km/h ; Y —
300 km/h ;
The maximum permitted speed must not be exceeded — this creates the risk of an accident. However, there are other rules associated with choosing a tyre by this factor. So, ideally, the actual driving speed should be at least 10 – 15% lower than the speed rating of the installed tyres — this will give an additional guarantee in case of emergency situations. In addition, in some tyre models, as the speed approaches the maximum, the upper limit of allowable load is reduced; see “Load Index” for details.
