Given that many manufacturers recommend using tires with a wider profile in summer and narrower profiles in winter, several sizes may be indicated in the service book. We do not recommend installing tires with a different size, since automakers have tested the car in various conditions and have selected the optimal tire size that provides the safest vehicle operation. Tires of recommended sizes have a certain circumference on the outer diameter, so installing tires of a different size will lead to distortion of the odometer and speedometer readings.
When choosing tires, pay attention to the permissible maximum speed of the tire (see table. 14.2). It is important that it is not less than the maximum speed of the car. In addition, the permissible load capacity of each tire (see table. 14.1) must not be less than half of the maximum weight on the relevant axle of the vehicle.
Depending on the conditions in which the tires will be used, their seasonality and tread pattern are selected.
In summer, during rain, when driving at high speed, the car may become uncontrollable, as the tire will seem to slide (swim) over the surface of the water. This effect is called hydroplaning. In order to avoid this, lamellas are applied to the tires (grooves) special shape, which are able to effectively remove water from the contact patch of the wheel and the road. Very often, such tires are marked accordingly - «RAIN» (rain) or «AQUA» (water). It should be noted that if there is no such marking, this does not mean at all that these tires cannot be used in the rain.
In winter, snowy and icy sections of the road create a problem for drivers. The car on such sections becomes poorly controlled, which can lead to an emergency. This problem is solved as follows: on winter tires, they make a rougher tread pattern and are often provided with spikes. These tires are labeled accordingly «M+S» («Mud» + «Snow» - mud and snow) and/or «WINTER» (winter).
Winter tires should not be used in the summer, as they become quite soft at elevated temperatures. Such tires in the summer are subject to rapid wear and do not provide a safe mode of operation of the car. Summer tires in winter, on the contrary, become very stiff and do not provide good grip.
Some manufacturers produce all-season tires that are suitable for use in both winter and summer conditions. But, as a rule, they are inferior in performance to seasonal tires. They are more difficult to manufacture, so they usually cost more than seasonal ones.
Sometimes there is an inscription on the tires «ALL SEASON» (all Seasons) or «ALL WEATHER» (any weather). When buying, you need to take into account that, perhaps, these tires were produced for hot countries, where the winter cold stays at around 0°C and, of course, are not suitable for our winter.
Make sure that the tires you purchase meet international and Russian standards. Tires that have passed certification are marked with the letter «E» (which indicates compliance with European standards) or inscription «DOT» (which indicates compliance with American standards), and sometimes bear both of these markings.
Regardless of international certification, all tires sold in Russia must have a certificate of conformity issued by the State Standard of Russia, which conducts its own tests. The seller must present the certificate at the first request of the buyer.