When choosing car tires, it is important to remember that it is of great importance to match the dimension of the tire to the dimension of the wheels. Everything is clear with the diameter - a 15'' tire with a diameter of 15'' should be put on a disk with a diameter of 15''. The confusion usually arises with the width of the tire and rim. Their discrepancy 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, handling may deteriorate, and driving performance auto. In order not to make a mistake 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) Convert the resulting value to inches: 1 cm \u003d 2.54 inches, divide 21.5 by 2.54, we get 8, 46 - round to 8.5

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

4) The resulting number is subtracted from the width of the tire and rounded up to tenths 8.5 - 2.38 \u003d 6.1

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

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

For discs with a diameter of 15 inches or more, the allowable error is 1.5 inches.

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

Correspondence table of tires and disks for passenger cars mobiles

Ø disk	Tire size	Disc rim width (in inches)
		Min.	Recom.		Max.
Series 80
Series 70
Series 65
Series 60
Series 55
Series 50
Series 45
Series 40
Series 35
Series 30

This is one of the simplest types of tuning. Why is this needed? There are many options. The most common reason is dislike appearance. Let's say you want the wheels to look spectacular. To do this, the disk must be larger in diameter. Well, or you bought a used car, and the design of the rims categorically does not suit you. Perhaps you liked some specific wheels, but their dimension is not included in the list recommended by the car manufacturer. You can also change the wheels for reasons of practicality. But how can the installation of such wheels turn out in the future? Let's figure it out.

First, let's recall the key parameters of the wheel.

• 185 - tire profile width in mm
• 65 - percentage of tire profile height to width
• R - designation of a tire of a radial design
• 15 - bore diameter in inches

So, there are several ways to move away from the size of a regular wheel.

1. Wider tire

When saving regular size increase the width of the tire profile while maintaining the percentage of height to width. In our example, we get 195/65 R15. It is important to know here that all cars are designed for the installation of snow chains with a size of at least 12 mm. Indeed, in some European countries, driving on mountain roads without chains is prohibited, and not a single self-respecting manufacturer will make a car so that it cannot be operated in the mountains of France or Switzerland. Therefore, an increase in the width of the tire profile is permissible in most cases by up to 24 mm. At the same time, the car will become a little softer on the move, and wider tires will improve braking performance.

2. Higher tire profile

We leave it the same, and increase the percentage of the tire profile height to width to 70. In our example, we get 185/70 R15. The outer diameter of the wheel increases by 20 mm, which is quite acceptable (remember the reserve for installing chains). Everything would be fine, but in our particular example, the factor intervenes that tires of this dimension are produced mainly for commercial transport and they are too rigid and expensive to install on a passenger car. However, in other dimensions, the situation may be different.

3. Change the diameter of the disc

The story of a friend's car is very indicative. He bought a Kia Rio with a 1.6 engine and a 6-speed automatic. The regular wheels of the car had a size of 185/65 R15. The owner drove through the summer season and was not happy with the car's stiff suspension and insufficient ground clearance. Then he decided to change the behavior of the car, not by tuning the springs with shock absorbers, but by working with the wheels. In preparation for the next summer season, he used forged wheels with a diameter of 14 inches, fully suitable for installation dimensions.

There is noticeably more air between the disc and the tire. Grew up and outside diameter wheels (by 9 mm). As a result, the smoothness of the ride has become fantastic. When overcoming road roughness, the car, which was not initially famous for its energy-intensive suspension, began to resemble ultra-comfortable Russian roads ah cars of the loganoid family. Soft, quiet, smooth. All the problems of dead Russian roads and hard Korean suspension have disappeared. He does not plan to drive, because a possible deterioration exchange rate stability At very high speeds, he doesn't care.

However, a decrease in the diameter of the disc is a very rare occurrence. Much more often it happens that the owner chooses wheels one or even two sizes larger. And "wraps" them in low-profile tires. At the same time, the overall dimensions of the wheel remain almost unchanged or grow within acceptable limits.

It looks impressive, but the smoothness of the ride suffers first of all. Yes, and there are much more chances to damage the wheel on a bad road, because the lower the height of the tire profile, the less the ability of such a tire to withstand shock loads. In everything you need to know the measure. Returning to our example, Rio and Solaris cars in expensive trim levels flaunt 16-inch wheels with 195/55 R16 tires. In this case, you can play a little with the dimensions. For example, a 195/60 R16 tire will fit in the wheel arch without any problems, since its outer diameter will increase by only 19 mm. The clearance will grow by a decent 9.5 mm, but about the softness of the ride, which is provided by 15-inch wheels basic modification, you can forget.

4. Increase the width of the disk and change the offset

A separate story when the owner of the car decides to install wider disks. Some people like it when the wheel protrudes a little beyond the arch. Please note that changing the dimensions of the wheel and tire can significantly increase the weight of the wheel assembly. Such weighting will negatively affect the life of the suspension elements and even the body, since large unsprung masses can cause resonant vibrations that the suspension is not designed for structurally. It is also important to remember such a parameter as wheel offset.

Those who like to change the offset of the rims, as a rule, tend to place the wheels wider. The aesthetic component of such changes is controversial, but the resource of the suspension elements will certainly decrease.

Consequences of increasing the overall dimensions of the wheel:

pros	Minuses
Ground clearance increase. On our roads every millimeter ground clearance on account. If the bottom of the car is 5–10 mm further from the potholes, then there is less chance of damaging it on a bad road.	The wheel can touch body parts. If the wheel width and diameter increase by no more than 24 mm from maximum size wheels recommended by the manufacturer, then this problem is not terrible for you. You can't put chains on after that.
Economy improvement. Economy improves slightly on country roads, especially on vehicles with gearboxes that have few gears (4 or 5).	Increase in car roll. Yes, the roll will increase slightly, due to the fact that the center of mass is now slightly higher. In practice, this means a slightly lower limiting rearrangement speed.
Changing the speedometer and odometer readings. Regular devices always overestimate the readings. You can check with GPS. And with new ones, a little big wheels, the testimony will come into line with reality. Plus or minus you decide. Still, such a discrepancy is made primarily for security reasons. We are for accurate instrument readings.	Decrease in dynamic characteristics. The new wheels are a little harder for the engine to turn, and they themselves are a little heavier.
Decreased wheel offset (when the wheels protrude more than wheel arches) provides a wider track, which raises lateral stability cars.	Wide disc is easily damaged when touching a curbstone. In addition, if the width of the disk is much larger than the nominal one, the tire carcass does not work correctly. It leads to increased tire wear.
In most cases appearance becomes more aesthetic and catchy.	Strongly protruding from the arches of the wheel overload wheel bearings and make driving difficult. It is worth getting the front wheel on the roughness of the road, as the steering wheel literally pulls out of your hands.

For calculations, it is convenient to use a tire calculator.

Legal aspect

By law, non-standard wheels are prohibited. Therefore, any experiments with the dimensions of tires or wheels are illegal. An exception is if the new dimension is allowed to be installed by the manufacturer. However, in reality, not everything is so scary: if wheel disks on a small car, you don’t have welded up to a width of 12 inches, if the diameter is not 19 or more inches, then such wheels will not arouse the interest of traffic police officers. But with obtaining a diagnostic card, problems will already arise.

But what if you put bigger wheels? - examination of the RF

Good day, dear readers. Today I want to answer immediately a lot of questions related to wheel sizes. Many of my readers do not understand what they mean and why they are needed at all! Today I will try to explain in a simple and understandable language what the dimensions of rubber on cars mean ...

The dimensions of the rubber wheel contain a lot of useful information, you just need to be able to read it. Without this information, you will not be able to choose the right tires for your car, they simply will not fit in size. Although now on the bodies of many brands there are special plates with recommendations, you just read them and go to the store to buy the same ones. However, there are not always such plates and you need to determine the dimensions of the tires yourself! A small clarification, I will only talk about overall dimensions, there have already been many articles about other characteristics, links will definitely be below.

I will talk about them using the example of my winter wheels, KAMA EURO 519, it should be noted that they are in no way inferior to their foreign counterparts. Read informative.

To begin with, the overall dimensions

I have a wheel size R16 205/55 , these are the so-called dimensions. Rubber is considered low profile (more).

The notorious letter R

Many mistakenly think (to be honest, I thought so too) that the first English letter R means the abbreviation "RADIUS"! But it's not! The letter R means radial tire, read the article -. This is such a method of assembling rubber and metal cord during production. Of course, you can also meet the letter D in front (diagonal), but such a designation is now really rare. In fact, this letter has nothing to do with size. Let's go further...

Disc diameter

The second number (in this case we have 16) indicates the diameter of the hole in the rubber, or which disc you can put this rubber on. We have 16, which means it's 16 inches! Remember that this size is always given in inches (1 inch = 25.4 mm). if we knock out our size, it turns out - 16 X 25.4 mm = 406.4 mm. The disc cannot be larger or smaller than the diameter of the wheel, you simply cannot put it on. That is, if the rubber is 16 (406.4 mm), then the disk should be 16 (406.4 mm).

Width

A large number almost always characterizes the width. In this case, this figure is 205. It is measured in millimeters, that is, the width of my wheel is 205 mm. The wider the rubber, the wider the track, respectively, the patency and adhesion increases.

Cord height

This is the smaller number that is applied through the fraction. In my case, this is 55, measured as a percentage of the width (of the larger number). What does it mean? To find the height (in my case) you need to calculate 55% of 205 mm. Thus it turns out:

205 X 0.55 (55%) = 112.75 mm

This is the height of the cord of our rubber, also an important indicator, see the figure.

Total wheel height

Let's calculate the total height of my wheel. What happens.

Rubber cord 112.75 X 2 (since the height is on both sides, top and bottom) = 225.5 mm

Under the disk 16 inches = 406.4

Total - 406.4 + 225.5 = 631.9

Thus, my wheel is a little more than half a meter high, namely 0.631 meters

Let's look at the most common tires that are used by most cars, there are three of them - these are R13, R14 and R15

Tire sizesR13

The most common of all isR13175/70 such are installed on many models domestic VAZ(although now departing).

What happens:

R13 - diameter 13 inches (multiply by 25.4) = 330.2 mm

Width 175

Height - 70% of 175 = 122.5

Total - (122.5 X 2) + 330.2 \u003d 574.2 mm

Tire sizesR14

One of the most common isR14175/65, are also installed on domestic VAZ models, more recent years of production, such models as Priora, Kalina, Grant, as well as on some inexpensive (folk) foreign cars - for example Renault Logan, Kia Rio, Hyundai Solaris etc.

What happens:

R14 - 14 inch diameter (multiply by 25.4) = 355.6 mm

Width - 175

Height - 65% of 175 = 113.75

Overall dimensions - (113.75 X 2) + 355.6 mm = 583.1 mm

Tire sizesR15

The most common example is -R15 195/65, installed on many foreign cars (folk) class, but in high trim levels.

What happens:

R15 - diameter 15 inches (multiply by 25.4) = 381 mm

Width 195

Height - 65% of 195 = 126.75

Total - (126.75 X 2) + 381 \u003d 634.5 mm

As you can see, it is not so difficult to calculate the size of the rubber.

Of course there is another one on the wheel useful information, I already wrote articles about it below. For you I will list the points, read useful and interesting:

In general, read the heading - there is much more information there. As you can see, all this information can be read from the tire, sometimes you can’t even believe it!

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

Diameter and dimensions

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

Marking

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

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

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

• R - means that the tire is a radial type. There is a diagonal design (indicated when marking - D), which is used quite rarely in the modern world. It is explained by the fact that the characteristics during operation are lower than that of the radial one.
• 16 - inner diameter of the wheel (in inches). If you need to convert the value to 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 to select disks. For disks, 16 is the outer (landing) diameter. The radius of the entire wheel is another value.

• 94 - the possible load on one wheel is about 670 kg. The value indicates the possible load.
• H- maximum speed, which 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 give Additional information about the tire, down to the number of the inspector at the manufacturing plant. You can decipher the values ​​in full, but the main parameters that will help give information when selecting are described above.

Size and wheels

To carry out correct selection tire diameter and size, you should consult a specialist, or the manufacturer's recommendations, to find out the appropriate values ​​\u200b\u200bfor a particular machine. Among all diameters winter tires and summer, the most popular can be distinguished: R19; R18; R17; R16; R15; R14.

Important: it is necessary to follow the recommendations - if the size does not match, 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 rubber wear, when installing tires with the wrong offset.

When you need to choose wheels for a certain tire size, you can use the table:

Disc width	Minimum tire width	Suitable tire width		Maximum tire dimensions
5	155	165	175	185
5.5	165	175	185	195
6.0	175	185	195	205
6.5	185	195	205	215
7.0	195	205	215	225
7.5	205	215	225	235
8.0	215	225	235	245
8.5	225	235	245	255
9.0	235	245	255	265
9.5	245	255	265	275
10.0	255	265	275	285
10.5	265	275	285	295
11.0	275	285	295	305
11.5	285	295	305	315
12.0	295	305	315	325
12.5	305	315	325	335

It is worth noting that not all selection values ​​\u200b\u200bare indicated in the table - there are wheels from 3 inches or more, but everything directly depends on the radius of the wheel that will be selected for a particular car. Therefore, it is necessary to rely primarily on the recommendations of the car manufacturer, or on the comments of a specialist.

Resizing

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

• Increase in width - it is permissible to increase this indicator by no more than 24 mm, 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 an R15 tire diameter 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 stopping distance will decrease, and the car will start to go a little softer, but the price of buying new tires will increase.
• Height - the installation will slightly increase the patency, but it is impossible to increase the indicator much. This will lead to the rapid erasure of tires on the car body.
• Wheel offset - some car owners seek to increase the width of the disk, 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 failure of the suspension. 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 seek to increase the diameter of the disc, and use low-profile rubber as tires. For example, with a tire diameter R16 and size 195/60, it is suitable for replacing a wheel with characteristics 185/65 and 15 radius - in this case, you will have to sacrifice driving performance and smoothness. There are times when a reduction in diameter leads to an improvement running characteristics machines, namely - to increase the softness of the suspension. But there will be downsides to this as well. high speeds the vehicle may lose directional stability.

The result is as follows: when choosing new rims and tires, the best solution would be a selection based on factory recommendations. To change the tire parameters, you need to clearly imagine what this can threaten during the operation of the car.

Installing and choosing modified tires on your own, without consulting a specialist, is not recommended, and can lead to failure of the entire car.

It is always better to purchase complete wheels right away, but if you suddenly had to start selecting tires according to disks, then don’t worry, now we will study all the features of this process so that even an inexperienced person can handle it.

Main parameters and their designation

First you need to familiarize yourself with the main parameters and their designation. The wheel diameter is indicated by the symbol "D" and is considered the most significant characteristic. It is very important to follow the dimensions recommended by the manufacturer. The increased diameter will contribute to the distortion of the speedometer readings. It is also possible for the wheel to rub over the elements of the body and chassis.

The diameter of the rims is designated "dd", but their width (the distance between the inner edges of the rim) is "Wd", and in the marking it is usually indicated in inches. Height also matters, this characteristic has the code "dt". Low profile tires wear out faster and are not suitable for all roads. If the condition of the road surface is not ideal, then it is better not to buy such tires, since in this case the load on the suspension increases, and there is a possibility of disk deformation. In addition, they are noisier.

"Wt" - tire width. For driving on a dry track, wide tires are better, as this shortens the braking distance. For urban environments and slippery roads It is recommended to use narrow tires.

Before talking directly about the selection of tires by disks, it is necessary to disassemble a little in the marking of one and the other. Let's start with disks. The marking may be embossed anywhere except on the inner surface facing the rim. To make it easier to understand, consider the decryption using a specific example.

Let's say you found the following code "6.5JJx13FH6x98ET20d62.1". The first is the width of the disk and it is indicated in inches, in our case it is 5.5. to convert this value to millimeters, multiply it by 25.4. This is followed by a Latin letter (P, D, B, K, J) or a combination of them (JJ, JK). This symbol characterizes the shape of the profile contour, the height of the shelves, their angle of inclination and the radius of curvature. "JJ" indicates that the car is full drive.

If you see the symbol “x” behind the letter designations, then this means that the disc has a one-piece design, but collapsible copies in the marking contain the “-” sign. Next, the diameter of the disks is indicated, followed by the hump index. This is a value indicating the annular protrusions along the rims. They have a very important function - fixing tubeless tires during turns. A simple hump is denoted by a single letter "H", flat, as in our case, "FH", and an asymmetric one - "AH". There are designs in which there are no humps.

The following is the value to be applied. Special attention when selecting tires for wheels, this is the location of the mounting holes, in our case “6x98”. This suggests that there are 6 of them, and the diameter of the circle is 98 mm. The number of holes ranges from 4 to 6, and the circumference can range from 98 to 137.9 mm. The following indicates the distance between the plane of attachment of the disk to the hub and its vertical axis. This parameter is called disc overhang and is denoted by a combination of letters "ET". The number following them indicates the offset value in millimeters, in our case it is 20 mm.

The overhang can be positive, zero, or negative. Suspension and steering are adjusted depending on this parameter. The diameter is indicated last in the marking. mounting hole. For passenger cars, this value is in the range from 50 to 70 mm. Quite often it is also stated maximum load, date of manufacture and method of production. Discs are available forged, cast and stamped.

Tire marking

If you decide to start selecting tires according to the width of the disks, then you definitely need to be able to decipher the rubber markings. After all, this code contains all the necessary information. You can find it on the side surface of the tire. However, it also indicates a lot of other information about rubber, starting from the country of the manufacturer, model and ending with the purpose and type. This information, of course, is of great importance, as it affects the quality of the product, but if we are talking about the selection of rubber for certain disks, then they do not play a decisive role.

But the most important information contained in a code called a type. To make it as clear as possible, consider the decryption using a specific example. Let's say you found the following code "225/50 R14" on the side of the rubber. The first number indicates the width of the profile in millimeters. Moreover, measurements are made taking into account the sidewalls. Next comes the height value, expressed as a percentage relative to the width. With us it is 50%, which means that in order to come to the size in millimeters, you need 225x50%, it turns out 112.5 mm.

The next symbol gives information about the construction of the cord. "R" means that the tire has a radial ply. And the number following it expresses the mounting size of the rim, it is indicated in inches. In fact, this is the most important information that is needed when selecting tires by size. The marking also contains a column with speed and load indices. There are many tables on the Internet in which these alphanumeric designations are translated into specific values ​​\u200b\u200bof loads and speeds.

What will help you choose the right tires?

The choice of rubber is a very responsible task, because if you put inappropriate tires on a car technical specifications tires, then problems cannot be avoided. These may be incorrect speedometer readings, and even wheel arches touching the rubber. How to find out what tires are needed if, for example, you bought a used car and faced the replacement for the first time?

There are several ways to do this. The easiest way is to look in the book for the operation of the machine, in it you will surely find the necessary data. Sometimes we don’t have such an opportunity, in which case you can look under the glove box lid, where there is a special table with the necessary information. True, there are cars where such a table is not provided. What to do?

Do not be discouraged, you can always go to specialized sites that sell tires, and by filling out the plate (year, brand and other information about vehicle), you will receive detailed information on tires that are ideal for your car. If you decide to put tires of a different size on the car, then the tire calculator will help you track the change in the linear dimensions of the rubber and the speedometer reading.

How to match tires and rims?

But there are cases, again, they are more often associated with supported cars, when it is necessary to select tires according to the size of the disks, because these two components should correspond to each other as much as possible. Then simple rules will help. For instance, the width of the rubber profile should be 25–30% over size disc rim. So, for example, if the width of the disk is 5.5 inches, then, adding 30% to this value, we get 7.15 inches or 185 mm. It is important that these two parts match in their central holes. But if for some reason this does not work out, then a special adjusting ring will come to the rescue. Its outer diameter corresponds to the disc hole, and its inner diameter corresponds to the hub.

But this is not all the features of selecting tires for. It is also necessary that the tires strictly correspond to the diameter of the circumference of the disc mount centers. A maximum run-up of 2 mm is allowed. In this case, special bolts with eccentrics are used for fixing. But it is best if these parameters match 100%.

In order not to miscalculate exactly with the choice, you can refer to special tables for selecting tires for disks, where their sizes and correspondence are indicated.

There is also such a thing as maximum load. Usually they rarely pay attention to it, since disk manufacturers make their products with a good margin of safety. However, if you decide to experiment and, for example, install wheels from a sedan on a jeep, then be sure to find out this characteristic. It is quite possible that the disk will not withstand such a load, and the first hole or hillock will lead to very sad consequences.