Tire sizes for 18. Selection of tires by rims - where should you look most carefully? Differences in tire marking

Every car owner is faced with the choice of tires for a car. This can be a change in seasonality (summer, winter), a planned replacement or a tire change in order to improve any characteristics. Before proceeding with the choice, each owner should know how to choose the right tires for his car - this means not only understanding what characteristics are required, but also parameters such as the outer diameter of the tire and suitable wheel sizes (recommended for installation).

Diameter and dimensions

The modern market offers a huge number of tires of different standard sizes for any conditions. But each car has its own allowable tire diameter dimensions. To find out which one is suitable for the car, you need to use the instruction manual for the car (if there is factory rubber) or use the markings that are applied to the tires.

Marking

It is applied to each tire, and contains all the information. An example would be 205/55 / ​​R16 94HXL:

• 205 - the indicator indicates the width of the tire in millimeters;
• 55 - ratio of height to width. In the considered variant, the value is 55%. If the value is absent, then the value is 80-82% (used on light commercial vehicles).

Important: if the car owner decides to install wider tires (for example, 215/55), then this will mean that the tires will be higher.

• R - means that the tire is radial type. There is a diagonal design (indicated by the marking - D), which is rarely used in the modern world. This is explained by the fact that the operating characteristics are lower than those of the radial.
• 16 - inner diameter of the wheel (in inches). If you need to convert the value into centimeters, then it is worth remembering that 1 inch is equal to 2.54 centimeters, and is calculated by multiplication.

Attention: the value is used for selection of disks. For discs, 16 is the outer (landing) diameter. The radius of the entire wheel is a different value.

• 94 - the possible load on one wheel is about 670 kg. The value indicates the possible load.
• H is the maximum speed that can be developed on tires (speed index).
• XL - the tire is made with a reinforced carcass, and has a margin of safety in case of "overload" of the car.

There are many markings that can provide additional information about the tire, up to the inspector number at the manufacturing plant. You can decipher the values ​​completely, but the main parameters that will help give information when selecting are described above.

Size and rims

To carry out the correct selection of the diameter and size of tires, you need to contact a specialist, or to the manufacturer's recommendations to find out the appropriate values ​​for a particular machine. Among all diameters of winter and summer tires, the most popular ones can be distinguished: R19; R18; R17; R16; R15; R14.

Important: it is necessary to follow the recommendations - if the standard size does not correspond, then it is possible that the tire, when driving, will touch the body, or, due to a shift in the center of gravity, some indicators will deteriorate, possibly rapid erasure of rubber, when installing tires with an incorrect offset.

When you need to select wheels for a specific tire size, you can use the table:

It is worth noting that not all selection values ​​are indicated in the table - there are rims from 3 inches and more, but everything directly depends on the radius of the wheel, which will be selected for a particular car. Therefore, it is necessary to rely, first of all, on the recommendations of the car manufacturer, or on the comments of a specialist.

Changing the size

Some car owners specifically change the radius of the wheels, and such changes are subdivided into several categories:

• Increase in width - it is permissible to increase this indicator by no more than 24mm, but only while maintaining the same height. Otherwise, the wheel will rub against the body, which will quickly render it unusable. An example would be the diameter of a R15 tire with a dimension of 185/65. After the increase, the characteristics will be 195/65 (24mm is the maximum expansion value, the average is 12). After that, the braking distance will decrease, and the car will go a little softer, but the price for buying new tires will increase.
• Height - the installation will slightly increase the cross-country ability, but it is impossible to increase the indicator much. This will cause the tires to quickly rub against the car body.
• Wheel overhang - some car owners strive to increase the width of the disc, and it turns out that the wheel turns out to be slightly protruding from the arch. Such a change is detrimental to the car, and will quickly lead to suspension failure. The optimal wheel offset is regulated by the manufacturer, and it is not recommended to change it.

• The outer diameter of the disc - car owners, sometimes strive to increase the diameter of the disc, and use low-profile rubber as tires. For example, with a tire diameter of R16 and a standard size of 195/60, it is suitable for replacing a wheel with characteristics of 185/65 and radius 15 - in this case, you will have to sacrifice driving characteristics and smoothness. There are times when a decrease in the diameter leads to an improvement in the driving characteristics of the machine, namely, an increase in the softness of the suspension. But this will also have disadvantages - at high speeds the car can lose directional stability.

The bottom line is the following: when choosing new rims and tires, the best solution would be a selection based on factory recommendations. To change the parameters of tires, you need to clearly understand what this could threaten when operating a car.

It is not recommended to install and choose modified tires on your own, without consulting a specialist, and may lead to the failure of the entire vehicle.

When choosing car tires, it is important to remember that matching the dimension of the tire to the dimension of the disks is of great importance. With the diameter, everything is clear - a 15 '' tire must be worn on a 15 '' disc. Confusion usually arises with the width of the tire and rim. Their non-compliance can lead to a number of completely undesirable consequences associated with the operation of tires. The contact patch may become irregular, tire wear may increase, and the handling and driving performance of the car may deteriorate. In order not to be mistaken with the choice, use the correspondence table.

You can also do the calculation yourself. To do this, consider an example for a tire with a width of 215 mm and a diameter of 16.

1) We translate the width of the rubber in cm: 215 mm = 21.5 cm

2) We translate the resulting value into inches: 1 cm = 2.54 inches, divide 21.5 by 2.54, we get 8, 46 - round up to 8.5

3) From the obtained value we take 25-30%, in our case: 2.38

4) Subtract the resulting number from the width of the tire and round to tenths 8.5 - 2.38 = 6.1

5) The rim width of the disc must be 6.1 inches or 155 mm.

For discs up to and including 14 "in diameter, an error of 0.5 to 1" is possible.

For discs with a diameter of 15 "inclusive, the allowable error is 1.5".

As a calculation, it is better to calculate the allowable range of values, namely, calculate 25% and 30%, where 25% will be the maximum, and 30% will be the minimum width of the disc rim.

Correspondence table of tires and wheels for passenger cars

Matching the disc width to the tire width affects the stability of the vehicle. To ensure safe and comfortable driving, it is necessary that the ratio of these parameters be within the optimal range - recommended by the manufacturer, otherwise the adhesion of the tire to the disc and the road surface deteriorates, the risk of road accidents increases.

Theoretical part

The vehicle operating instructions indicate the dimensions of the tires and wheels. But many car enthusiasts are trying to fit larger discs on the car, as they believe that such actions will increase the stability of the vehicle. This opinion is not entirely correct. If you slightly increase the rim of the product, then you can get the following advantages:

• increase in speed;
• improved handling;
• increasing the stability of the machine.

With an increase in the disc more than the permissible norm, negative consequences are possible:

• deterioration of adhesion - the wheel will touch the wing of the car;
• increased load on the transmission;
• reduced controllability of the car.

If you want to install, for example, low-profile tires to make driving easier, keep in mind that such actions can lead to negative consequences:

• an increased risk of damage to discs when driving on an uneven road surface (pits, ledges, and so on);
• an increase in the load on the suspension of the machine while driving over holes and other irregularities.

The ideal option is the selection of products, taking into account the compatibility of tires and wheels in size. It can be achieved taking into account:

• the car dealer's recommendations - the conformity of the width of the disc and the rubber is indicated in the car manual;
• data of special tables for the selection of wheels and tires by size.

It is possible to select the standard size of rubber for the size of the disc and vice versa, using special tables, taking into account the width of the rim of the disc, it should be 25-30% less than the width of the rubber profile. For example, for rubber 175 / 80R14, the width is 175 mm, the profile height is 80%, and the disc diameter is 14 inches. We calculate the width of the profile in inches - 175mm = 6.89 inches, if you subtract 30% from this value and round the resulting number to the nearest value of the rim of the disc, we get 5 inches. It is estimated that a 5-inch rim is suitable for a 175 / 80R14 tire.

Installing too large (Figure 1) and too small (Figure 2) wheels on the vehicle.

R12 tires

Series 82

Tires 125R12: recommended rim width 3.5; minimum 3.0; maximum 4.0.
Tires: 135R12 recommended wheel width 4.0; minimum 3.5; maximum 4.5.
Tires 145R12: recommended wheel width 4.0; minimum 3.5; maximum 5.0.
Tires: 155R12 recommended wheel width 4.5; minimum 4.0; maximum 5.0.

Series 70

R13 tires

Series 82

Tires 145R13: recommended wheel width 4.0; minimum 3.5; maximum 5.0.
Tires 155R13: recommended wheel width 4.5; minimum 4.0; maximum 5.5.
Tires 165R13: recommended wheel width 4.5; minimum 4.0; maximum 5.5.
Tires 175R13: Recommended rim width 5.0; minimum 4.5; 6.0 maximum.

Series 80

Tires 135 / 80R13: recommended rim width 3.5; minimum 3.5; maximum 4.5.
Tires 145 / 80R13: recommended wheel width 4.0; minimum 3.5; maximum 5.0.
Tires 155 / 80R13: recommended wheel width 4.5; minimum 4.0; maximum 5.5.
Tires 165 / 80R13: recommended wheel width 4.5; minimum 4.0; maximum 5.5.

Series 70

Tires: 135 / 70R13 recommended wheel width 4.0; minimum 3.5; maximum 4.5.
Tires: 145 / 70R13 recommended wheel width 4.5; minimum 4.0; maximum 5.0.
Tires: 155 / 70R13 recommended wheel width 4.5; minimum 4.0; maximum 5.5.
Tires: 165 / 70R13 recommended disc width 5.0; minimum 4.5; 6.0 maximum.
Tires: 175 / 70R13 recommended disc width 5.0; minimum 5.0; 6.0 maximum.
Tires: 185 / 70R13 recommended wheel width 5.5; minimum 5.0; maximum 6.5.
Tires: 195 / 70R13 recommended wheel width 6.0; minimum 5.2; maximum 7.0.

Series 65

Tires 155 / 65R13: recommended wheel width 4.5; minimum 4.0; maximum 5.5.
Tires 165 / 65R13: recommended wheel width 5.0; minimum 4.5; 6.0 maximum.
Tires 175 / 65R13: Recommended rim width 5.0; minimum 5.0; 6.0 maximum.

Series 60

Tires 175 / 60R13: recommended rim width 5.0; minimum 5.0; 6.0 maximum.
Tires 185 / 60R13: recommended wheel width 5.5; at least 5.5; maximum 6.5.
Tires 205 / 60R13: recommended wheel width 6.0; at least 5.5; maximum 7.0.

Series 55

R14 tires

Series 82

Tires 145R14: recommended wheel width 4.0; minimum 3.5; maximum 5.0.
Tires 155R14: recommended wheel width 4.5; minimum 4.0; maximum 5.0.
Tires 165R14: recommended wheel width 4.5; minimum 4.0; maximum 5.5.
Tires 175R14: Recommended rim width 5.0; minimum 4.5; 6.0 maximum.
Tires 185R14: recommended wheel width 5.5; minimum 4.5; 6.0 maximum.

Series 80

Series 70

Tires 165 / 70R14: recommended disc width 5.0; minimum 4.5; 6.0 maximum.
Tires 175 / 70R14: recommended disc width 5.0; minimum 5.0; 6.0 maximum.
Tires 185 / 70R14: recommended wheel width 5.5; minimum 5.0; maximum 6.5.
Tires 195 / 70R14: recommended wheel width 6.0; at least 5.5; maximum 7.0.
Tires 205 / 70R14: recommended wheel width 6.0; at least 5.5; maximum 7.5.

Series 65

Tires 155 / 65R14: recommended wheel width 4.5; minimum 4.0; maximum 5.5.
Tires 165 / 65R14: recommended wheel width 5.0; minimum 4.5; 6.0 maximum.
Tires 175 / 65R14: recommended rim width 5.0; minimum 5.0; 6.0 maximum.
Tires 185 / 65R14: recommended wheel width 5.5; minimum 5.0; maximum 6.5.
Tires 195 / 65R14: recommended wheel width 6.0; at least 5.5; maximum 7.0.

Series 60

Tires 165 / 60R14: recommended disc width 5.0; minimum 4.5; 6.0 maximum.
Tires 175 / 60R14: recommended disc width 5.0; minimum 5.0; 6.0 maximum.
Tires 185 / 60R14: recommended wheel width 5.5; minimum 5.0; maximum 6.5.
Tires 195 / 60R14: recommended wheel width 6.0; at least 5.5; maximum 7.0.
Tires 205 / 60R14: recommended wheel width 6.0; at least 5.5; maximum 7.5.

Series 55

R15 tires

Series 82

Tires 125R15: recommended rim width 3.5; minimum 3.0; maximum 4.0.
Tires 135R15: recommended wheel width 4.0; minimum 3.5; maximum 4.5.
Tires 145R15: recommended wheel width 4.0; minimum 3.5; maximum 5.0.
Tires 155R15: recommended wheel width 4.5; minimum 4.0; maximum 5.0.
Tires 165R15: recommended wheel width 4.5; minimum 4.0; maximum 5.5.
Tires 185R15: recommended wheel width 5.5; minimum 4.5; 6.0 maximum.

Series 80

Series 70

Tires 175 / 70R15: recommended wheel width 5.0; minimum 5.0; 6.0 maximum.
Tires 195 / 70R15: recommended wheel width 6.0; at least 5.5; maximum 7.0.
Tires 235 / 70R15: recommended rim width 7.0; minimum 6.5; maximum 8.5.

Series 65

Tires 185 / 65R15: recommended wheel width 5.5; minimum 5.0; maximum 6.5.
Tires 195 / 65R15: recommended wheel width 6.0; at least 5.5; maximum 7.0.
Tires 205 / 65R15: recommended wheel width 6.0; at least 5.5; maximum 7.5.
Tires 215 / 65R15: recommended wheel width 6.5; minimum 6.0; maximum 7.5.
Tires 225 / 65R15: recommended wheel width 6.5; minimum 6.0; maximum 8.0.

Series 60

Tires 195 / 60R15: recommended wheel width 6.0; at least 5.5; maximum 7.0.
Tires 205 / 60R15: recommended wheel width 6.0; at least 5.5; maximum 7.5.
Tires 215 / 60R15: recommended wheel width 6.5; minimum 6.0; maximum 8.0.
Tires 225 / 60R15: recommended wheel width 6.5; minimum 6.0; maximum 8.0.

Series 55

Tires 185 / 55R15: recommended wheel width 6.0; minimum 5.0; maximum 6.5.
Tires 195 / 55R15: recommended wheel width 6.0; at least 5.5; maximum 7.0.
Tires 205 / 55R15: recommended wheel width 6.5; at least 5.5; maximum 7.5.
Tires 225 / 55R15: recommended wheel width 7.0; minimum 6.0; maximum 8.0.

Series 50

Tires 195 / 50R15: recommended wheel width 6.0; at least 5.5; maximum 7.0.
Tires 205 / 50R15: recommended wheel width 6.5; at least 5.5; maximum 7.5.
Tires 225 / 50R15: recommended rim width 7.0; minimum 6.0; maximum 8.0.

Series 45

R16 tires

Series 65

Series 60

Series 55

Tires 205 / 55R16: recommended wheel width 6.5; at least 5.5; maximum 7.5.
Tires 225 / 55R16: recommended wheel width 7.0; minimum 6.0; maximum 8.0.
Tires 245 / 55R16: recommended wheel width 7.5; minimum 7.0; maximum 8.5.

Series 50

Tires 205 / 50R16: recommended wheel width 6.5; at least 5.5; maximum 7.5.
Tires 225 / 50R16: recommended wheel width 7.0; minimum 6.0; maximum 8.0.
Tires 235 / 50R16: recommended wheel width 7.5; minimum 6.5; maximum 8.5.
Tires 255 / 50R16: recommended rim width 8.0; minimum 7.0; maximum 9.0.

Series 45

Tires 195 / 45R16: recommended wheel width 6.5; minimum 6.0; maximum 7.5.
Tires 205 / 45R16: recommended wheel width 7.0; minimum 6.5; maximum 7.5.
Tires 225 / 45R16: recommended wheel width 7.5; minimum 7.0; maximum 8.5.
Tires 245 / 45R16: recommended rim width 8.0; minimum 7.5; maximum 9.0.

Series 40

R17 tires

Series 55

Series 50

Series 45

Tires 215 / 45R17: recommended wheel width 7.0; minimum 7.0; maximum 8.5.
Tires 225 / 45R17: recommended wheel width 7.5; minimum 7.0; maximum 8.5.
Tires 235 / 45R17: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 245 / 45R17: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 255 / 45R17: recommended wheel width 8.5; minimum 8.0; maximum 9.5.

Series 40

Tires 215 / 40R17: recommended wheel width 7.5; minimum 7.0; maximum 8.5.
Tires 235 / 40R17: recommended wheel width 8.5; minimum 8.0; maximum 9.5.
Tires 245 / 40R17: recommended wheel width 8.5; minimum 8.0; maximum 9.5.
Tires 255 / 40R17: recommended rim width 9.0; minimum 8.5; maximum 10.0.
Tires 265 / 40R17: recommended rim width 9.5; minimum 9.0; maximum 10.5.
Tires 275 / 40R17: recommended rim width 9.5; minimum 9.0; maximum 11.0.
Tires 285 / 40R17: recommended rim width 10.0; minimum 8.5; maximum 11.0.

Episode 35

Tires 245 / 35R17: recommended wheel width 8.5; minimum 8.0; maximum 9.5.
Tires 265 / 35R17: recommended rim width 9.5; minimum 9.0; maximum 10.5.
Tires 335 / 35R17: recommended rim width 11.5; minimum 11.0; maximum 13.0.

R18 tires

Series 50

Series 45

Series 40

Tires 225 / 40R18: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 235 / 40R18: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 245 / 40R18: recommended wheel width 8.5; minimum 8.0; maximum 9.5.
Tires 265 / 40R18: recommended rim width 9.5; minimum 9.0; maximum 10.5.

Episode 35

Series 30

R19 tires

Series 50

Series 45

Series 40

Tires 225 / 40R19: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 245 / 40R19: recommended wheel width 8.5; minimum 8.0; maximum 9.5.
Tires 255 / 40R19: recommended rim width 9.0; minimum 8.5; maximum 10.0.
Tires 275 / 40R19: recommended rim width 9.5; minimum 9.0; maximum 11.0.

Episode 35

Tires 225 / 35R19: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 235 / 35R19: recommended wheel width 8.5; minimum 8.0; maximum 9.5.
Tires 245 / 35R19: recommended wheel width 8.5; minimum 8.0; maximum 9.5.
Tires 255 / 35R19: recommended rim width 9.0; minimum 8.5; maximum 10.0.
Tires 265 / 35R19: recommended rim width 9.5; minimum 9.0; maximum 10.5.
Tires 275 / 35R19: recommended rim width 9.5; minimum 9.0; maximum 11.0.
Tires 285 / 35R19: recommended rim width 10.0; minimum 9.5; maximum 11.0.
Tires 295 / 35R19: recommended rim width 10.5; minimum 10.0; maximum 11.5.

Series 30

Tires 265 / 30R19: recommended rim width 9.5; minimum 9.0; maximum 10.0.
Tires 275 / 30R19: recommended rim width 9.5; minimum 9.0; maximum 10.0.
Tires 285 / 30R19: recommended rim width 10.0; minimum 9.5; maximum 10.5.
Tires 295 / 30R19: recommended rim width 10.5; minimum 10.0; maximum 11.0.
Tires 305 / 30R19: recommended rim width 11.0; minimum 10.5; maximum 11.5.
Tires 345 / 30R19: recommended rim width 12.0; at least 11.5; maximum 12.5.

Episode 25

R20 tires

Series 40

Episode 35

R21 tires

Episode 35

Series 30

Tires 255 / 30R21: recommended rim width 9.0; minimum 9.0; maximum 10.0.
Tires 285 / 30R21: recommended rim width 10.0; minimum 10.0; maximum 11.0.
Tires 295 / 30R21: recommended rim width 10.5; minimum 10.0; maximum 11.0.

Episode 25

R22 tires

Series 30

Episode 25

Conclusion

For the stability of the vehicle, it is necessary to comply with the width of the discs and the width of tires specified by the vehicle manufacturer. If you want to increase the size of disks or tires, to improve the appearance of the car or its characteristics, you should use special tables indicating the relationship between the parameters of tires and rubber. At the same time, keep in mind: even if you have chosen the correct size of the indicated products, there is a possibility that the disc will not be able to be installed on the car due to the design features of the car. For example, the disc will rest against the suspension parts or the caliper. This situation may arise due to the cast shape of the disc, therefore, before mounting the tire on the wheel, you should first try it on.

Some things sound boring and difficult to remember, but you need to know them. Especially for motorists. Especially those who consider themselves specialists and have their own opinion on any matter. The devil is in the little things, and this article is about just one such little thing.

There is no radius for a tire

Many now do not even understand what I am driving at. “Well, radius, so what? I have wheels 195-65R15, radius 15, everything is written, why are you being clever ?! " Here's what I'm clever about. R15 has nothing to do with the radius. Neither R nor 15.

Now on the Internet you can find a lot of information, only such trifles as marking of car tires are not among the most demanded. We'd better discuss the engine power or the number of "goodies" in the cabin, right? And we will leave the choice of wheels to the manager in the store. Well, or ask a friend. He knows for sure! He already has the third car!

In fact, understanding these boring numbers will not hurt even just for general development. Moreover, this will help save money and influence the behavior of the machine, but more on that later. So far - a pure educational program, so that later you can understand each other well.

So 195 / 65R15. A classic case. Let's squat down next to our car. The first number is the width of the tread, roughly speaking, the width of the tread. Expressed in millimeters. That is 195 mm. is the width of your wheel. Most have no problems understanding this figure.

Through the fraction 65 is the profile size. Expressed as a percentage of the width. Not in millimeters! The profile is the part of the tire "sticking out above the disc". Sidewall. That is, the height of this sidewall will be 195x65% = 125.75 mm. Not 65 mm. And not something else. Moreover, it clearly follows from this scheme that the height of 65% with a width of 195 will be one, and if the tire is marked (conditionally) 225 / 65R15, it will be completely different! 225x65% = 146.25 mm. Although the numbers 65 are the same!

R is the radial construction of the tire, or rather, the way in which the metal cord is laid inside it. Once upon a time, the design of the tire involved diagonal bracing, but that was a long time ago. Nowadays you can hardly find "diagonal" tires, everything is entirely radial, and the letter R will not tell anyone anything new, only disputes about the notorious radius will cause ...

And finally, the number 15. This is the diameter. The diameter of the seat of the tire, the inner diameter, the part that is in contact with the disc. Expressed in inches. 1 inch = 2.54 cm. That is, 15x2.54 = 38.1 cm This is also the outer diameter of the disc, if anyone hasn't guessed ...

Which tires can and cannot be used?

And then the fun begins. We can play with these numbers if we want to put different tires (disks) on the car. Ideally, the main thing is that the overall diameter does not differ, or does not differ significantly. Example.

The 195 / 65R15 wheel has the following overall diameter: 38.1 cm - inside, plus 125.75 mm x2 = 251.5 mm (there is a profile both above and below). Let's translate into centimeters for simplicity, we get 38.1 cm + 25.15 cm = 63.25 cm. Here's how! This is the total diameter of the wheel.

Now, if you want to put other wheels, the car owner must understand the following: automakers understand this figure in the same way as we do. Considering the wheel diameter, the suspension, braking system and bodywork are designed. Therefore, for the same car model (for example, for the Volkswagen Polo sedan), three wheel dimensions are officially allowed. The simplest version is content with 175 / 70R14 (total diameter 60.06 cm), 185 / 60R15 (60.3 cm) and 195 / 55R15 (59.55 cm).

It turns out that the "wheel 14" is MORE, albeit slightly, than the wheel by 15 in the case of 195/55. This is to the question raised above, about putting on more wheels for the winter ... You need to carefully calculate everything. Will a larger diameter number mean a larger wheel overall? Not always.

Do you want to choose a tire for your car, but don't know much about tire labeling? It's not a problem! In this section, we will help you figure out: what are the parameters of the tire, what they mean, and what kind of tire is suitable for your car.

Decoding of tire marking.

195/65 R15 91 T XL

195 is the width of the tire in mm.

65 - Proportionality, i.e. the ratio of the height of the profile to the width. In our case, it is equal to 65%. Simply put, with the same width, the larger this figure, the higher the tire will be and vice versa. This value is usually referred to simply as “profile”.

Since the tire profile is a relative value, it is important to take into account when choosing rubber that if instead of the 195/65 R15 standard size you want to put tires with the size 205/65 R15, then not only the width of the tire will increase, but also the height! Which is unacceptable in most cases! (except for the cases when both of these standard sizes are indicated in the car manual). You can calculate the exact data on the change in the outer dimensions of the wheel in a special tire calculator.

If this ratio is not indicated (for example, 185 / R14C), then it is equal to 80-82% and the tire is called full-profile. Reinforced tires with such markings are usually used on vans and light trucks, where a high maximum wheel load is very important.

R- means a tire with a radial cord (in fact, now almost all tires are made this way).

Many people mistakenly think that R- stands for the radius of the tire, but this is precisely the radial design of the tire. There is also a diagonal design (denoted by the letter D), but recently it has practically not been produced, since its performance characteristics are noticeably worse.

15 - wheel (disk) diameter in inches. (It is the diameter, not the radius! This is also a common mistake). This is the "landing" diameter of the tire on the disc, i.e. it is the inner size of the tire or the outer one at the rim.

91 - load index. This is the maximum permissible load per wheel. For cars, it is usually done with a margin and when choosing tires is not a decisive value, (in our case, IN - 91 - 670 kg.). For vans and small trucks, this parameter is very important and must be observed.

Tire Load Index Table:

T- tire speed index. The larger it is, the more speed you can ride on this tire (in our case IS - N - up to 210 km / h). Speaking about the tire speed index, I would like to note that with this parameter the tire manufacturer guarantees the normal operation of the rubber with the constant movement of the car at the specified speed for several hours.

Speed ​​Index Table:

American tire markings:

There are two different markings for American tires. The first one is very similar to the European one, only the letters "P" (Passanger - for a passenger car) or "LT" (Light Truck - light truck) are put in front of the standard size. For example: P 195/60 R 14 or LT 235/75 R15. And another marking of the tire, which is fundamentally different from the European one.

For instance: 31x10.5 R15(corresponds to European standard size 265/75 R15)

31 is the outer diameter of the tire in inches.
10.5 is the width of the tire in inches.
R- a tire of radial design (older models of tires were with a bias design).
15 is the inner diameter of the tire in inches.

Generally speaking, apart from the unusual inches, the American tire marking is logical and more understandable, unlike the European one, where the tire profile height is variable and depends on the tire width. And here everything is simple with the decoding: the first number of the standard size is the outer diameter, the second is the width, the third is the inner diameter.

Additional information indicated in the marking on the sidewall of the tire:

XL or Extra Load- a reinforced tire, the load index of which is 3 units higher than that of conventional tires of the same standard size. In other words, if a load index of 91 is indicated on a given tire, marked XL or Extra Load, then this means that with this index, the tire is able to withstand a maximum load of 670 kg instead of 615 kg (see the table of tire load indices).

M + S or M&S tire marking (Mud + Snow) - mud plus snow and means that the tires are all-season or winter. Many summer SUV tires are labeled M&S. However, these tires must not be used in winter because winter tires have a completely different rubber composition and tread pattern, and the M&S badge indicates a good cross-country performance of the tire.

All Season or AS all-season tires. Aw (Any Weather) - Any weather.

Pictogram * (snowflake)- rubber is intended for use in harsh winter conditions. If the sidewall of the tire does not have this mark, then this tire is intended for summer use only.

Aquatred, Aquacontact, Rain, Water, Aqua or pictogram (umbrella)- special rain tires.

Outside and Inside; asymmetrical tires, i.e. it is important not to confuse which side is external and which is internal. When installed, the Outside lettering should be on the outside of the car, and Inside on the inside.

RSC(RunFlat System Component) - RunFlat tires are tires on which you can continue driving a car at a speed of no more than 80 km / h with a FULL pressure drop in the tire (in case of a puncture or cut). On these tires, depending on the manufacturer's recommendations, you can drive from 50 to 150 km. Different tire manufacturers use different designations for RSC technology. For example: Bridgestone RFT, Continental SSR, Goodyear RunOnFlat, Nokian Run Flat, Michelin ZP, etc.

Rotation or an arrow on the sidewall of the tire indicates a directional tire. When installing the tire, the direction of rotation of the wheel indicated by the arrow must be strictly observed.

Tubeless is a tubeless tire. In the absence of this inscription, the tire can only be used with a camera. Tube Type - means that this tire must be used only with a tube.

Max Pressure; maximum allowable tire pressure. Max Load - the maximum permissible load on each wheel of the vehicle, in kg.

Reinforced or the letters RF in the standard size (for example 195/70 R15RF) mean that this is a reinforced bus (6 layers). The letter C at the end of the dimension (eg 195/70 R15C) denotes a truck tire (8 layers).

Radial This marking on a rubber in a standard size means that it is a tire of a radial design. Steel means there is a metal cord in the tire construction.

Letter E(in a circle) - the tire complies with the European ECE (Economic Commission for Europe) requirements. DOT (Department of Transportation - US Department of Transportation) - American quality standard.

Temperature A, B or C heat resistance of tires at high speeds on a test bench (A is the best indicator).

Traction A, B or C- the ability of the tire to brake on a wet road surface.

Treadwear; the relative expected kilometers traveled versus the US specific standard test.

TWI (Tread Wear Indiration)- indicators of tire tread wear indicators. The TWI wheel can also be marked with an arrow. The gauges are evenly spaced at eight or six places around the tire circumference and indicate the minimum tread depth allowed. The wear indicator is made in the form of a protrusion with a height of 1.6 mm (the minimum tread size for light vehicles) and is located in the groove of the tread (usually in the drainage grooves).

DOT- Coded manufacturer address, tire size code, certificate, production date (week / year).