Smart choice rims depends on technical characteristics, indicating all parameters, namely width, diameter, offset, as well as DIA (hub mounting diameter) and PCD (drilling parameters).

You also need to know the marking designation. It indicates the standard parameters of any type of wheel products:

• stamping;
• alloy wheels;
• forged.

Markings are indicated on the inside. Typically, manufacturers duplicate them in accompanying documents and on packaging if the product is new.

Disk options

To determine what the marking means, you need to know the width and diameter of the wheel product.

Drilling or bolting

This is one of the most difficult parameters to study, indicating the diameter of the mounting bolts. Drilling is measured from the center area of ​​the stud to the opposite area where the element is located on the wheel.

Quite often, manufacturers indicate the disc bolt pattern parameters using shot depending on the number of holes for fastening.

Let's assume the figures are 6/222.25. The first number shows the number of drillings for fastening the bolts, and the second number indicates the drilling in millimeters.

Disc offset

This indicator is marked with the English letters ET. What is ET in disks and why is it needed? The indicator indicates the distance from the plane of the wheel product to the middle zone of the rim. The mating surface of the wheel product indicates the pressing plane of the disk to the hub.

Departure parameters can be:

• with zero indicator;
• with negative;
• with positive.

Zero offset indicates that the plane of the disc corresponds to its middle zone. Thus, the lower the indicator, the more the wheel product protrudes from the outside of the car. If the overhang indicator is increased, this means that the disc is deeper into the interior of the car.

It is also necessary to take into account the fact that depending on the width of the product, the overhang indicators differ. Manufacturers indicate in the documentation accompanying the vehicle a smaller offset value for wheels with a large width.

What is HUMP(H)?

The hump is the protrusion of a ring on a disc rim. This element is used as protection against car tires coming off. Usually 2 humps (H2) are used for a wheel.

In some cases, a hump may not be used or only one may be used, depending on the vehicle configuration. Types of Humps:

1. combined (CH);
2. flat (FH);
3. asymmetrical (AH).

PCD Disc Parameters

The PCD value refers to the diameter of the circle of the center holes on the wheel rim. That is, this is the diameter of the holes for fastening the bolts.

DIA drive option

The DIA parameter indicates the diameter of the hole located in the center of the disk. Casting manufacturers prefer to create a large DIA center hole diameter. This is done to ensure that the wheels are applicable and universal for all types of cars.

Although hub size may vary depending on model vehicle, the auto disk is installed using an adapter ring or bushing.

Marking

As an example, consider the markings of the 9J x20H PCD 5×130 ET60 DIA 71.60 wheel rim:

1. The number 9 indicates the width, measured in inches. To convert inches to centimes, the total figure is multiplied by 25.4.
2. The letter J indicates the design elements: the shape of the disc flanges. This parameter does not play an important role in the selection.
3. The letter X denotes the indivisibility of the disc.
4. The number 20 indicates the landing diameter of the wheel product. This indicator corresponds to the fit of a car tire.
5. The letter H denotes the presence of one hump or ridge on the rim.
6. The abbreviation is PCD 5×130, where the number 5 indicates the number of drillings for fastening the nuts or bolts and the number 130 indicates their PCD diameter in millimeters.
7. The ET60 marking indicates disc offset. In this situation the figure is 60 mm.
8. The DIA value 71.60 indicates the diameter of the center drill. Typically, DIA corresponds to the fit of the hub and is indicated in millimeters. If the DIA is greater than the hub diameter, then a centering ring is used to install the disc.

The following information is also included with the label:

ISO, SAE, TUV - these abbreviations indicate the organizations that tested the wheel product, similar to the Russian GOST. The standards that correspond to the wheel marking are also indicated.

Maxload indicates the permissible load on a car wheel. This indicator is indicated in kilograms and pounds.

What does parameter 700c mean?

This designation is used for large types of wheels on SUVs and Nivas. According to the accepted ISO classification, this figure is 29 inches. Typically 700c wheels are used for off-road racing.

Due to the use of 29 inch wheels:

• management indicators are improved;
• braking distance on unpaved surfaces is reduced and aerodynamics is increased;
• the vehicle's cross-country ability on soft soils and sand increases;
• it becomes possible to install powerful brakes.

To select wheels that match a particular type of car, it is recommended to determine the diameter of the wheel and analyze the markings indicated on the rim. Also, do not forget that safe driving ultimately depends on this element.

The first and second columns specify standard tire and wheel sizes. The remaining columns have the dimensions desired for installation. The calculator will help determine tolerances and alternative selection options.

The tire calculator allows you to compare the dimensions of tires of different sizes. For example, choose wider tires, but keep the outer diameter of the wheel the same, or find out how much the vehicle's ground clearance will change if you install tires of a different profile.

To select an alternative size, you need to indicate the standard or existing tire size in one half of the calculator, and the desired or alternative size in the adjacent half.

The calculator displays the recommended rim width for a particular tire size, as well as the outer diameter and width of the wheel. The most important parameter is the outer diameter of the wheel. You should pay the most attention to its changes.

The second important parameter is the actual height of the tire profile. It is usually expressed as a percentage of the width: for example, 205/55 R16, where 55 is 55% of the tire width. That is, 205*55/100=112.75 mm is the actual profile height of this tire.

Tires of different widths, standardly installed on a car, have different profile heights in percentages, but the same in millimeters. For example, tires with dimensions 275/40 R20 and 315/35 R20 have a profile height of 110 and 110.25 mm, respectively.

Some features of tire selection:

• The wider the tires, the better the handling, but the resistance to aquaplaning is worse and the rutting is felt more strongly, and the comfort decreases - low-profile tires are stiffer.
• Lower profile - heavier wheel. This is due to the fact that the disc is heavier than the rubber, the weight of the wheel increases and this worsens the performance of the suspension. In addition, the mass of the metal is distributed closer to the outer edge of the wheel and increases the moment of inertia (for cars with a powerful engine this is not significant).
• As the profile increases, the car becomes more rolly, reacts worse to steering, but goes over bumps more easily, the tires are less sensitive to the sharp edges of holes, and comfort becomes better.
• A significant change in the outer diameter of the wheel leads to distortion of vehicle instrument readings, in particular, mileage and speed.

Our tire calculator - professional calculations in the shortest possible time!

Wheel rims have many parameters - not only the diameter and the number of holes for bolts. But mostly motorists pay attention to these two characteristics. When you choose a product, be sure to check the necessary parameters car rims provided by the manufacturer of your vehicle.

It is important to realize that any non-compliance with factory requirements has a negative impact on the functioning of the suspension. This, in turn, contributes to accelerated wear of the tire and various parts of the chassis. There is a possibility that your wheel will come off while driving, which can lead to disastrous consequences. For this reason, the installation of such products must be accompanied by their further monitoring during operation.

Transcript example

As a rule, the usual characteristics of car wheels look like this:

6.5jx155/112H2ET45d57.1.

So, what do these letters and numbers mean?

• 6.5 is the seating width of the disc rim, indicated in inches. It is calculated as follows: 6.5*25.4=165.1 mm. This value is directly related to the width of the tires. Each tire has a permissible rim width. This component value is determined using calculations based on the tire size. If the sizes of the two elements do not match, you will have problems with tire beading.
• The letter J, like D, P, K, JJ and others, encrypts technical data about the edges of a car disk rim (its height, shape and structure). The most popular types of disc rims today are J (for cars with single-wheel drive) and JJ (for all-wheel drive cars). Beads directly affect how the tire mounts and the amount the tire moves in some situations.
• The 5/112 marking hides the properties of mounting the disc to the hub. The number 5 indicates how many holes for fastening the bolts should be on the product, and the number 112 indicates the diameter of the circle where the centers of these holes should be located. Sometimes component manufacturers mark this parameter separately and mark it with the letters PCD or Pitch Circle Diameter.

• The letter H in the characteristics of wheel rims indicates the characteristics of the disk rim flanges, as well as the protrusions that they have. These protrusions are required for tires without tubes. They ensure correct installation of the tire and wheel.
• The ET45 symbol in the car wheel parameters indicates the wheel offset in millimeters.- this is the distance between the central disk axis, as well as the plane of application of the disk. It must meet the production requirements of your car with maximum accuracy, as it is one of the key parameters for setting the characteristics of the suspension and steering mechanism. One hub has one offset for any tire size and type. Some manufacturers also designate this data separately as OFFSET or DEPORT.
• d 57.1 (DIA) - diameter of the hole located in the center of the disk. It must match the size of the cylinder located on the hub. In addition to the centering function, the cylinder takes on the load on the studs. If the center hole of the desired product exceeds the dimensions of the cylinder, you will need to use. They can be purchased at tire centers.

Peculiarities

In the characteristics alloy wheels it is also envisaged that they have a maximum load level. For this reason, even if the dimensions of alloy wheels externally match the parameters of your car, the load for them must be clarified with the manufacturer. There are two options on how to do this:

• if the wheels are from Russian manufacturers, then this indicator is in the disk passport;
• if from foreign ones, you will need to find this information on their website. As a rule, each manufacturer has data on the guaranteed use of cast components on a particular car in a special catalog. If you have found your car in the catalog and have your eye on the corresponding product, you can purchase it without fear.

It happens that the dimensions of the cast product completely coincide with the required ones. However, it cannot be installed on a car. During installation, the disc begins to rest against the suspension or brake mechanism. This situation is due to the shape of the stamping or casting spokes. For this reason, before carrying out the tire beading procedure, you should always try on the disk on the front and rear car axles, having first screwed it on with at least two bolts.

It is sometimes not easy for many novice car enthusiasts to choose their own iron friend. This is because their labeling reflects a large number of parameters and characteristics. This article will discuss the method of deciphering the size of the disk and choosing it for the car.

Reading characteristics

The entire string of parameters printed on the disk can be divided into several components. It might look something like this: 7jx16 H2 5x130 ET20 d74.1. To decipher the disk sizes, you need to consider each element in order.

It is worth noting that sometimes the location of parameters in a line may be swapped and slightly different in symbols. But the general algorithm for deciphering disk sizes on a car is always the same.

Width

The width of the rim is indicated in inches and comes first in the characteristics line. In fact, this is one of the determining parameters when choosing. Based on this value, the tire width will be selected in the future. Marking examples: 8.5 12, 9.5.

Experienced drivers claim that greater width significantly affects the handling and dynamics of the car.

Side edge design marker

Immediately after the number with the width of the disk there is a letter value. As a rule, it carries little information for the car enthusiast and is used mainly by service specialists. In most cases it is marked with the letter J. But it can also be JJ, K, JK, B, P, D.

Disc diameter

In deciphering disk dimensions, the symbol for the design of the side flanges is followed by a numerical value of the diameter in inches. It is also one of the main parameters. Changing the diameter of the rim upward can also change the size of the tire used. And this, in turn, will affect handling on the highway. For example, on low-profile tires, all the road irregularities will be clearly felt, and the entire load will fall on the shoulders of the suspension.

Humps

Next in order comes the designation of humps. These are protrusions along the edges that allow the tire to be mounted more securely. Can take values ​​H, H2, X. Here H is a regular hump, X is a truncated one. The coefficient after it is the number of sides on which the hump is located.

PCD

The next parameter in order is sometimes called PCD. It is marked something like this: 5x130. The first number in the entry shows the number of disk mounting bolts, and the second is the diameter at which they are located in millimeters. This is one of the most important parameters when deciphering disk sizes.

The values ​​can vary over very small ranges, down to tenths of a millimeter. Therefore, if the specification is not selected accurately, there is a possibility that the bolts will not be able to fit into place. As a result, the fastener will not be tight. This means that you will then have to carry out frequent balancing and repairs.

Departure

This parameter consists of numbers and letters. Maybe this is ET20. In short, it means the distance between the plane of the disk and can be negative or positive. The first option will visually make the disk more convex relative to the car. The second one is in-depth.

A significant change in disc offset affects the displacement of the steering axle, increases bearing wear and, in some cases, worsens handling. Car manufacturers strictly regulate the size of the permissible overhang, and grossly violating it means affecting some of the car’s parameters, which may worsen.

Center hole diameter

It is measured in millimeters and designated by letters and numbers. For example, like this - d85. When decoding disk sizes, you should pay special attention.

Extra options

When deciphering disk sizes, other characteristics can be used. For example, maximum load to disk. Passenger cars use discs with a safety margin that should be sufficient for its needs. But if it turns out that it will be moved to another type of equipment, for example, an SUV, then the nearest small hole may damage the disc.

Typically the load is specified in pounds. To get kilograms from them, you need to divide the existing value by 2.2.

When deciphering the sizes of alloy wheels and subsequent installation, it may not fit the car. This condition is called X-factor. And it is connected with the fact that alloy wheels can be of the most varied shapes, while fully complying with the declared and required dimensions. Therefore, to avoid buying an unsuitable model, you should first install it on the car, at least with a couple of bolts and turn it slightly. If nothing interferes or rests, then the disc is ideal for the car.

How to choose the right disk?

In addition to technical characteristics, the choice can also be influenced by aesthetic properties, as well as the manufacturing method.

Appearance is chosen based on personal preference. Some people like more spokes, others like fewer petals.

It is also worth knowing that wheels are divided into two large categories: steel and alloy.

Steel or stamped are made from a sheet of metal, which is subsequently joined by welding. This approach makes it possible to significantly reduce the cost of production. Besides, steel wheels easier to repair and restore. Although this is required quite rarely, since they have good strength. On the other hand, the stamped approach creates inaccuracy in production, which promises problems with subsequent balancing. Also, the significant weight of steel increases the overall weight.

Alloy wheels are lightweight. Their production process allows them to create a wide variety of shapes and designs. They cost a little more, but as a result, aesthetics and practicality take such discs far ahead.

The alloy type is also in turn divided into two categories: cast and forged. The first type has a granular structure, which makes the product fragile. This is a known problem with alloy wheels. When used for a long time on uneven roads, they tend to split.

A forged disc has a fibrous structure, which provides special plasticity and does not allow the disc to form chips and cracks. It is very difficult to deform or destroy it.

A small example of decryption

It is worth making out the markings on a single product. For example, decrypt disk sizes in Valdai. There is this designation - 17x6 6x222.25 Et115 Dia160. Here the first value is the diameter of the disk in inches. This is followed by the width for which the tires are selected.

This is followed by the number of bolts and the diameter at which they are placed. These are 6 and 222.25 respectively. Et115 is a disk offset. In this case, it means that it is 115 mm inward from the mounting plane. That is, the disk is convex.

Dia160 is the diameter of the central hole in millimeters.

Finally

Careful decoding when choosing them will allow you to accurately select the necessary parameters and not become a victim of an unreasonable purchase. Knowing about their characteristics will be useful not only for novice car enthusiasts, but also for more experienced ones.

Stamped or cast wheels: what to prefer and what parameters to choose?

Any car enthusiast sooner or later faces the problem of choosing and purchasing tires. At the same time, many people want to purchase tires at the same time. wheel disks. This is right. Because by assembling the wheels once, you will subsequently save your money and time by not having to stand in huge queues at the tire shop twice a year. All you need to do is balance the wheels (and this can be done in advance, without waiting for the tire change season) and change them at any car service center or even yourself. In addition, by installing, for example, alloy wheels on your car, you can significantly improve the appearance of your car.

But here the question arises - how to choose the right wheels for your car?

Let's start with what kind of wheels you want: or stamped ones? Both have their pros and cons. The positive aspects of stamped disks are their simplicity and reliability - even if the disk is damaged (dented), its shape can be restored by rolling it on a special machine, or in the field even just with a hammer. Also, in most cases, stamping is cheaper than its cast counterpart. Among the minuses, one can note the “banality” appearance, as a rule, greater weight and the fact that such a disc is extremely inconvenient to wash from the inside, and in winter this is especially important. With alloy wheels the opposite is true. Pros: a huge selection of designs and even colors, lighter weight (15-30%) and ease of maintenance. Cons: alloy wheels are more expensive and cannot be repaired if damaged. A damaged disk must be replaced with a new one, although many workshops now offer to repair alloy wheels. We do not recommend doing this due to the peculiarities of the production technology of alloy wheels, but this is a topic for another article.

Now, let’s say you’ve decided on the type of disk. But the next question arises: how to choose a wheel that is suitable for your car? And what parameters do you need to know for the right choice? Let's say right away that most car manufacturers include in the car's operating instructions full sizes does not provide disks, limiting itself only to indicating the mounting diameter and width of the disk, and in rare cases, indicating the offset of the disk. You will have to find out the missing parameters from the dealership specialists or salespeople.

Dimensions of stamped and cast wheels

The complete disk marking looks, for example, as follows:
6.5Jx16 H2 5/112 ET50 dia-57.1. Now let's decipher:
6.5 – the width of the rim of the disk (measured in inches) – the width of the part on which the tire is put on;
J– shape of the side edge. There are other designations, but a simple car enthusiast does not need to know this;
x– the rim is non-separable (the vast majority of passenger car wheels are now produced this way);
16 – nominal bore diameter (measured in inches). This diameter must be strictly equal to the tire diameter. It is unacceptable, for example, to install a tire with a diameter of 16 on a 16.5-inch wheel.
H2– Hump – a small annular protrusion running along the rim of the disk closer to its edges. It is necessary for reliable fixation of the tubeless tire on the rim. The number 2 in this case indicates the presence of 2 humps, i.e. one near each of the edges;
5 – number of holes for attaching the disc to the car;
112 – PCD (Pitch Circle Diameter) – diameter of the circle passing through the centers of the mounting holes (measured in mm);
ET(OFFSET can also be written) – disc offset (measured in mm) – the distance from the mating plane to an imaginary plane passing through the middle of the disc rim (in our case 50mm);
Dia(writing D, Centerbore is also possible) – central hole (measured in mm).

Now let’s figure out which sizes can be changed and within what limits, and which should remain “untouched”.

The width of the rim depends on the width of the tire mounted on it. For example, a 205/55R16 tire can be installed on a wheel with a width of 6 to 7.5 inches, with a recommended width of 6.5 inches. Therefore, the size of the disk rim can be chosen within these limits. The tire and wheel matching table will help you correctly.

Bore diameter – there is even more choice here. The minimum diameter is always indicated in the car's instructions and can increase almost indefinitely. But keep in mind that the larger the disk diameter, the lower the tire profile will be, and this in turn negatively affects ride comfort, but improves the car's handling at high speeds.

Number of mounting holes – this parameter remains unchanged.

PCD, in most cases, cannot be changed either. Although some manufacturers of alloy wheels (OZ Racing, AEZ, DOTZ) provide special bolts with eccentrics that allow you to screw, for example, wheels with PCD 100mm onto cars with PCD 98mm. On cars that are fastened with nuts, similar eccentric nuts are used. Maximum value the displacement of such bolts and nuts is 1.2mm, so the difference in the PCD of the disk cannot exceed 2.4mm.

Overhang – a change in offset is possible in the direction of decreasing it. But it is desirable that such a reduction be within the limits of 1 cm. As a rule, changes in the direction of increasing the number of departures are impossible, because The LOWER the offset number, the MORE the disk “protrudes” out of the car relative to the wheel with the “native” offset, and vice versa. Thus, as the overhang number increases, the disc will be recessed into the car more, and the likelihood that it will rest against suspension or brake parts increases significantly.

The central hole in the stamped wheel must be equal to the diameter of the car hub in order for it to be properly centered on the hub. With alloy wheels the situation is somewhat different. Currently, most companies producing alloy wheels, both domestic and foreign, make wheels with a universal central hole. And for alignment, a special centering ring is used, the outer diameter of which is equal to the diameter of the hole in the disk, and the inner diameter is equal to the diameter of the car hub. Let me give you an example. The disk size 6.5x16 5/114.3 et45 dia-72.6 can be installed on Mitsubishi cars with a hub diameter of 67.1mm and on Toyota cars with a hub diameter of 60.1mm. So, in order not to make two different cast disks, the manufacturer produces one disk with a larger central hole, in our case 72.6 mm, and two centering rings - the first 72.6/67.1 and the second 72.6/60.1. When installing a wheel on a car, the ring is inserted into the disc, after which the disc is installed on the car, centered on the hub, and tightened with bolts or nuts. After this, the centering ring does not bear any load and does not in any way affect the driving characteristics of the car. Centering rings can come complete with discs or be supplied for an additional fee. I repeat, stamped discs cannot have such rings.

Alloy wheels. Underwater rocks.

Disks also have a very important parameter that is not indicated in the labeling - maximum load. Therefore, even if the disk fits your car in all sizes, it is better to check the load. For domestic wheels you can see it in the disk passport, for foreign ones you will have to look for it on their websites on the Internet.
And the last thing you need to keep in mind when buying discs is that there is a so-called X factor- this is when all the dimensions of the disk coincide with the required ones, but the disk still does not fit on the car and rests on suspension parts or brake mechanisms. This is due to the very form of stamping or casting spokes. Therefore, we always recommend to our clients, before beading a tire onto a wheel, to first try it on the car on the front and rear axles, tightening it with a couple of bolts and carefully turning it.

Currently, the vast majority of disk manufacturers have catalogs of guaranteed disk applicability on their Internet sites. If your car is in such a catalog and there is a disc you like for it, then you can safely buy it, which means it is fully suitable in all respects.
Now the choice has become much easier than it might seem at first glance. Good luck with your purchase))