Deciphering disk sizes on auto

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:55

It is sometimes not easy for many novice motorists to choose rims for their iron friend on their own. This is because their marking 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.

Read characteristics

The entire line 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 size of the disk, you need to consider each element in order.

It is worth noting that sometimes the location of the parameters in the string can change places and slightly differ in characters. But the general algorithm for decrypting disk sizes on auto is always the same.

Width

Rim width is indicated in inches and comes first in the specification 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 say that the wider width significantly affects the handling and dynamics of the car.

Flange Design Marker

Immediately after the number withthe disk width is followed by a letter value. As a rule, for a car enthusiast, it carries little information 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 wheel sizes, the bead flange design symbol is followed by the numerical value of the diameter in inches. It is also one of the main parameters. Changing the diameter of the disk in a larger direction can also change the size of the tire used. And this, in turn, will have an impact on handling on the track. For example, on low-profile tires, all the bumps in the road will be clearly felt, and the entire load will fall on the shoulders of the suspension.

Humps

Next in order is the designation of humps. These are protrusions along the edges, which allow you to more securely mount the tire. They can take the 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 is sometimes referred to as PCD. It is marked something like this: 5x130. The first digit in the entry shows the number of disk mounting bolts, and the second - the diameter on which they are located in millimeters. This is one of the most important parameters when deciphering disk sizes.

Values can vary in very small ranges, up to tenths of a millimeter. Therefore, if the characteristic is not matched exactly, there is a possibility thatthe bolts won't 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 so - ET20. In short, it means the distance between the plane of the disk and the axis of symmetry. Can be negative and positive. The first option will visually make the disk more convex relative to the car. The second is in-depth.

Significant change in the offset of the disk affects the displacement of the steering axle, increases bearing wear and in some cases worsens handling. Auto manufacturers strictly regulate the size of the permissible departure and grossly violating it means hitting some parameters of the car, which may worsen.

Center hole diameter

Measured in millimeters and indicated by letters and numbers. For example, so - d85. When deciphering the size of the disk, you should pay special attention.

Additional parameters

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

Usually, the load is indicated in pounds. To get kilograms from them, you need to divide the existing value by 2, 2.

When decryptingalloy wheel sizes and subsequent installation, it may not fit the vehicle. This state is called the X factor. And it is connected with the fact that alloy wheels can be of the most diverse shapes, while fully complying with the declared and required dimensions. Therefore, in order to avoid buying an unsuitable model, it should first be installed on the car, at least for a couple of bolts and slightly scrolled. If nothing interferes, does not rest, then the disc is ideal for cars.

How to choose the right disc?

In addition to technical characteristics, the choice may be influenced by aesthetic properties, as well as the method of manufacture.

Appearance is chosen based on personal preferences. Some like more needles, some like fewer petals.

It's also worth knowing that rims fall into two broad categories: steel and alloy.

Steel or stamped are made from a sheet of metal, subsequently connected by welding. This approach can significantly reduce the cost of production. In addition, steel wheels are easier to repair and rebuild. Although this is required quite rarely, as they have good strength. On the other hand, the stamped approach generates inaccuracies in production, which promises problems with subsequent balancing. Also, the significant weight of the steel adds to the overall mass.

Alloy wheels are lightweight. The process of their production allows you to create a wide variety of shapes and designs. They cost a little more, butas a result, aesthetics and practicality take these discs far ahead.

The alloy look is further 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. With prolonged use on rough roads, they tend to split.

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

Small decryption example

It is worth disassembling the markings on a single product. For example, to decrypt the sizes of disks on Valdai. There is such a designation - 17x6 6x222, 25 Et115 Dia160. Here the wheel diameter in inches comes first. This is followed by the width that the tires are matched to.

Then comes the number of bolts and the diameter on which they are placed. These are 6 and 222.25 respectively. Et115 is the disc offset. In this case, it means that the axis of symmetry is 115 mm inward from the mounting plane. That is, the disk is convex.

Dia160 - diameter of the central hole in millimeters.

In conclusion

Careful interpretation of the sizes of rims 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 motorists, but also for more experienced ones.