What is the car ring?
The outer edge of the car wheel is called rim. The rim holds the tire and gives the wheel a round shape. The rim plays an important role in the beauty and the way the car moves on the road. The car rim must have high resistance and strength, because in addition to the weight and load of the car and its passengers, it bears lateral forces, heat caused by friction and stress caused by braking.
Car Ring Structure
The car rim is a part of the wheel and in turn includes many components. In the car rim structure, we are faced with concepts such as rim edge, rim spokes, curb protrusion, rim opening, offset, circular diameter of screws, valve valve, rim center cover, and screw pattern.
Ring edge
The outermost part of the car rim on the sides is called the lip. The edge depends on the type of rim design. For example, in sports rims, the rim is wider than the center of the rim, and they are often called rim rims. A rim with a wide rim is always installed on the rear axle and a rim with a thin rim is always installed on the front axle.
Ring blades
Ring spokes are designed with great sensitivity and precision and connect the edges of the rim to the center plate. The spokes of the rim are also beautiful and increase the attractiveness of the side view of the car.
Bump inhibition
The protrusions on the inside and behind the edges of the rim are called safety humps, which prevent the air from escaping by restraining and sticking the tire to the edges of the rim.
The middle crater
The center hole of the car rim is called Center Bore, which is the same size as the diameter of the middle protrusion of the wheel disc. Contrary to what many people think, the weight of the car is completely applied to the middle opening and the middle edge of the rim.
Off
Offset is the distance between the center of the rim and the location of the rim on the wheel disk. Offset can be zero, positive or negative. If the place where the wheels are screwed is exactly in the middle of the rim, the offset is zero. When the width of the wheel and the imaginary line in the middle of the rim is inclined to the inside of the fender, the offset is defined as positive, and when the width of the wheel and the imaginary line in the middle of the rim is inclined to the outside of the fender, the offset is defined as negative.
The circular diameter of the screws
The car rim is closed and secured with the help of screws to the holes on the wheel disc. The diameter of the hypothetical circle that the screws pass through is called the Pitch Circle Diameter, the unit of measurement of which is mm. PCD 120 x 5 means the wheel has 5 screws and the diameter of the circle connecting the screws is 120 mm. Wheels with the same PCD are interchangeable between cars.
Valve valve
Valve is a valve located on the outer edge of the rim that controls the tire pressure. In most of today's cars, Valve is equipped with a tire pressure monitoring system or TPMS, which sends a warning to the driver if it detects a decrease in the air pressure inside the tire.
Cap in the middle of the rim
The center cap is usually a plastic piece that covers the middle opening of the rim. The cap fits easily into the middle opening of the rim, but to remove it, the rim must be removed from the car.
The screw pattern
The car rim sits on the wheel disc. In fact, as mentioned, the rim is closed with the help of screws to the holes on the wheel disc. The bolt pattern in the rims depends on the PCD and is variable. But the patterns of 4, 5, 6 and 8 screws are more popular.
