- 6 - rim width in inches;
- J - symbol of the rim profile;
- 15 - rim diameter for the tire in inches;
- H2 - symbol for the shape of the landing flanges of the rim;
- ET - symbol for rim offset;
- 45 - rim offset in millimeters.
Comment. Rim offset (ET) is the distance between the plane dividing the wheel rim in half (plane equidistant from the rim flanges) and mating (fixing) wheel plane.
In addition, the wheel disk has two more very important parameters that allow it to be used on a specific car model - this is the diameter of the location and the number of mounting holes, as well as the central hole of the disk. These parameters are set by the design of the vehicle hub and must strictly comply with it (see «Reference data»), as they provide the correct and reliable fastening of the disc to the hub.
The car is equipped with tubeless tires. The tire designation, for example, 185/65R15 88Q, stands for:
- 185 - profile width in millimeters;
- 65 - the ratio of the profile height to its width in percent;
- R is the designation of the radial tire;
- 15 - tire diameter in inches;
- 88 - load index (maximum permissible tire load 560 kg);
- Q - speed index (maximum allowed speed 160 km/h).
Maximum tire load (MAX LOAN) duplicated in deciphered form, together with an indication of the maximum allowable pressure (MAX AT) air in the tire.
When giving recommendations in choosing one or another, the manufacturer proceeds from the conditions for ensuring maximum stability, controllability, maneuverability and safety of the car. So, a stake with a long overhang can touch the details of the mechanisms, with a smaller one - increase the load on the hub bearings and can lead to unpredictable behavior of the car during emergency braking or in the event of a failure of one of the brake system cones. High-profile tires can touch body parts at maximum suspension travel, and wide tires can rub against the car's side member or fender at large turning angles. A tire with a lower load index may burst under the maximum load of the car, a decrease in the speed index is fraught with destruction of tires when driving at high speed.
Tires that can be installed on a car are divided into three types: summer, winter and all-weather. If the car is operated all year round, and the winter is snowy, then it is better to have two sets of wheels: with winter and summer tires. Winter tires are made from softer rubber, which allows them to «petrify» at negative temperatures, and on the tread there are narrow wavy slots - lamellae. This allows the tire to better target the roughness of the pavement. Winter tires can be marked M+S or M.S on the sidewalls. The possibility of using studded tires in winter depends on the specific operating conditions of the car. Keep in mind that studs are designed to improve tire grip only on slippery hard surfaces such as ice or packed snow. In other cases, the mils are useless, and on asphalt they even slightly worsen the grip of the tire with the road.
The use of a winter tire in the summer leads to intensive wear.
All season tires can be used all year round. They are distinguished from other tires by the inscription ALL SEASON or TOUS TERRAIN on the sidewall. In terms of their performance, they behave satisfactorily in various weather conditions, but in summer they lose in terms of technical indicators to summer tires, and in winter to winter ones.
The tread pattern can be universal or directional and is not regulated by the requirements of the vehicle manufacturer. With a directional tread pattern, the inscription ROTATION and an arrow indicating the direction of rotation of the wheel when the car moves forward are entered on the sidewall of the tire.
A special case of a directional pattern is asymmetric. In this case, the inscription OUTSIDE is applied to the sidewall, which must be on the outside during installation.
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