The first wheel was invented long before the advent of cars. When and by whom this greatest discovery was made is still not reliably known. It is believed that it was first used in Mesopotamia more than five millennia ago, and the first wheels with spokes appeared in Asia Minor (in the territory of modern Turkey) another fifteen hundred years later, then they quickly spread around the world. Be that as it may, any, even ultramodern, rims are a further improvement of one of the most ancient inventions of mankind.
Rims are made of steel and light alloys. Steel is stamped from a single sheet, and then the parts are joined by welding. The result is a fairly high-quality and durable product. They are easily repaired in case of damage. Their main disadvantages are the following: they are too large in mass and do not differ in high precision manufacturing.
Alloy alloys are not inferior in strength to steel, but at the same time they give ample opportunities in the field of wheel design. In addition, they have higher manufacturing accuracy and excellent heat dissipation from the brake assembly.
Regardless of the material and method of manufacture, all of these products are standardly labeled. Disk labeling contains all the necessary product information. It is located on its inner surface, and must also be contained on its packaging (box, sticker, booklet, etc.).
So what is disk labeling? How to understand the conventions? Let us consider how marking of rims is performed, using a specific example: 8.5Jx16H2 5 * 120 ET 45 d 74.1, where
- 8.5 - disk width (in inches).
- J is the shape of the flange. Contains information about the so-called humps (protrusions along the rim of the tubeless tire disc ) designed to securely fix the bead.
- x - rim type (detachable is indicated by the symbol "-", one-piece - "x").
- 16 - the diameter of the rim (in inches).
- H2 - information about the availability of humps.
- 5 * 120 - the number of bolts or nuts, as well as the diameter of the mounting holes.
- ET 45 - offset (removal) of the disk (in millimeters). Departure is the distance between the attachment (the part of the wheel with which it is in contact with the hub) and the conditional plane that divides the wheel in half. It can be either positive or negative or zero.
- d 74.1 - diameter of the hub (in millimeters).
In addition, disc labeling provides additional information. The following is indicated:
- disc manufacturer
- production date (usually a year and a week: 1209 means that the disk was made in the 12th week of 2009);
- stamp of the regulatory body;
- maximum permissible wheel load (in pounds or kilograms);
- allowable tire pressure;
- brand of x-ray control;
- Gosstandart brand (in Russia it is Rostest).
Now you know how disk marking is done. All the details were given above. Such a seemingly complicated procedure, such as deciphering the labeling of disks, will not become your "Chinese letter". You can independently choose what is right for your car.