A wheel rim is one of the components of a car wheel. It serves as the basis for mounting the tire, as well as for transmitting torque from the drive shafts to it. Depending on the technology and material used, there are several types of wheel rims, each of which has both advantages and disadvantages. And the parameters of the wheel rims, such as the size of the rims and other indicators, determine the choice in favor of one option or another.
DIA: what does it mean when choosing disks
When it comes to purchasing new components, it is quite difficult to do without expert advice. When choosing designs for their car, many are not even familiar with the basic parameters. Therefore, before installing components on your car, you need to study all the vehicle indicators specified in the technical passport of the manufacturer.
DIA value
Their list primarily includes stem, PCD, DIA, product width, etc. Wheel marking plays an important role. Its indicator is usually indicated on the label or in the technical data sheet. This information is displayed for all types of structures in a standard format.
Before correctly reading the marking, the car owner must understand what a certain term may mean:
- A is the diameter of the central hole of the disk;
- B - width;
- ET - the offset of the structure is used to determine the distance between the space where the rim is applied to the hub and the internal sphere of the structure.
Important!
The mating plane is the base that connects the wheel rim to the vehicle hub. When choosing designs, you should not be guided only by the external data of the components. Otherwise, you can worsen the technical condition of the vehicle, as well as its handling on smooth asphalt or off-road.
Disc overhang is divided into positive, negative and zero. In the latter option, the mating plane of the product is determined between the middle of the structure. If they coincide with each other, then the wheel type is considered zero.
Sometimes it happens that the overhang indicator is smaller, then the structure will stick out unsightly from the outside of the vehicle. However, some motorists like wide components. Therefore, they choose the first option. In the second case, everything looks different: the higher the ET value, the tighter the structure fits inside the car.
Note!
The width of the structure may differ from the disc offset value. Many manufacturers of automotive components indicate in the technical data sheet for the car that wheels with a larger width have a lower offset indicator.
PCD means the circle diameter of the wheel rim holes. This indicator determines the location of the wheel design mounting holes.
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Often, beginners and even experienced drivers cannot decipher the symbols indicated on car wheels. To avoid mistakes when choosing tires, you need to carefully study all the indicators. What is DIA on disks is the diameter of the central hole. On many manufactured alloy wheels, in order to give the car a presentable appearance, the diameter of the central hole DIA is made large. To correctly select the size of a car hub, experts recommend choosing an adapter ring or bushing.
What is Wheel Rim DIA
DIA is the size of the central hole (CO) of the wheel rim. Despite its apparent simplicity, a lot depends on the size of this parameter. The diameter of the central heating center on different brands of cars may differ, since the car is designed for certain performance characteristics. That is, the parameters of one machine may differ significantly from the parameters of another.
The wheel is the main element of a vehicle. Therefore, its design features can also be different, providing the car with factory characteristics. The DIA parameter may sometimes be designated by the letter “D”. It can be found in the operating instructions, in the “Technical Specifications” table, section “Wheels”.
Also, it is applied to the disk itself, along with other parameters. For example, 4*108/6J/DIA 63.3/R15. If there is no information, you will have to use a caliper and measure the diameter of the central center yourself. For all discs, the diameter is indicated in mm.
Sometimes the same wheels are produced for different car models. For example, on a VAZ-1117/1118/1119 Kalina (04-), with a standard bolt pattern of 4×98, the DIA parameter is 58 mm, and for a VAZ 2101-2107 Zhiguli/Lada with the same bolt pattern 4×98, the DIA is 60 mm.
Design mounting hole
Product mounting hole
The mounting diameter of the wheel rim is as follows - 7.5 j x16 H2 5/112 ET 35 d 66.6:
- 7.5 is the width of the structure.
- J is a feature of automotive designs.
- x is the inseparability of the wheels.
- 16 — landing diameter.
- H2 - two protrusions.
- 5/112 is determined by the number of mounting holes for bolts or nuts, and 112 serves as the diameter of the circle.
- ET 35 - product size is 35 mm.
- d 66.6 - diameter of the central hole.
Tire and wheel sizes part 1. Marking and selection of car rims.
Marking and selection of car rims. A striking example of how easily different measurement systems can coexist and how deeply this confusion has entered our lives.
| Example of disk marking: 6.5J×15 H2 5/112 ET39 d57.1 |
- Number and bore diameter of the location of the wheel rim mounting holes. - fastening to the car
- Disc central hole, hub diameter. — fastening to the car
- Wheel rim width. — fastening to the tire (tire)
- Wheel rim diameter. — fastening to the tire (tire)
- Wheel offset. Wheel removal. - wheelbase width
- Disc rim flanges, side flanges. — fastening to the tire (tire)
- Rim shelves and bumpers. - fastening to the tire (tire)
- Other possible designations.
- Wheel mount. The procedure for tightening bolts (nuts).
- Recommended tightening torque depending on the wheel thread diameter
You can familiarize yourself with the decoding of tire designations here.
The number and mounting diameter of the location of the wheel rim mounting holes.
6.5J×15 H2 5/112 ET39 d57.1 - “five holes with a diameter of 112 mm”
| ||
| 3 holes | 4 holes | 5 holes |
To independently determine PCD = diameter “B” in Fig. necessary:
| ||
Disc central hole, hub diameter.
6.5J×15 H2 5/112 ET39 d57.1 - “hole for hub 57.1 mm”
| d 57.1 - Diameter of the centering hole on the disk. Must exactly match the diameter of the landing cylinder on the hub. Often the same wheel (wheel rim) is offered for cars from different companies, so the central hole in the wheel rim must be different. Because in addition to the centering function, the landing cylinder has another, no less important one - it partially takes on the load that falls on the mounting bolts (studs). Therefore, if the centering hole of the disk you like is larger than the hub mounting cylinder, you will have to use special centering rings, which can be bought at tire centers, or ordered somewhere. The external and internal dimensions of the centering ring must correspond exactly to the diameters of the hub cylinder and the centering hole of the disk, respectively. |
Wheel rim width.
A disc wheel consists of two main parts: the rim and the disc itself. The disc is the central part of the wheel, with which the wheel is attached to the car hub with bolts or nuts. The rim is a cylindrical part of a wheel with a special profile, which is located perpendicular to the disk and serves to mount a rubber tire on it.
6.5J×15 H2 5/112 ET39 d57.1 - “disc (rim) seat width 6.5 inches”
| 6.5 is the seating (!not overall!) width of the disk rim in inches (sometimes the value of the disk width in the marking is indicated as a fraction 6 1/2). The width is measured not along the outer sides of the rim, from edge to edge, but along the so-called “disc shelf”, on which the sidewalls of the tire rest. The width of the rim and tire must strictly correspond to each other so that the tires, after installation on the rims, have the optimal shape specified by the manufacturer. DIMENSIONS: are always given in inches (1 inch = 25.4 mm), except for designs, which will give dimensions in millimeters. |
Wheel rim diameter.
6.5J×15 H2 5/112 ET39 d57.1 - “wheel diameter (size) 15 inches”
15 – landing (!not overall!) diameter of the wheel rim in inches, which must correspond to the landing diameter of the tire. Passenger cars use wheels with a diameter of 12 to 32 inches, the most common diameters being 14-16 inches. 1 inch=25.4 mm.
Wheel offset. Wheel removal.
6.5J×15 H2 5/112 ET39 d57.1 - “positive wheel offset 39 mm”
| ET=39 — Disc offset or offset in mm (this parameter may also be marked OFFSET and DEPORT). Usually it can be 10 mm less than the standard without any problems and usually depends on the width of the rim. The smaller the offset, the wider the wheelbase. Disk offset is the distance between the mounting plane of the wheel (the plane of which the disk is pressed against the hub) and the middle of the disk width (an imaginary plane passing through the middle of the rim). To determine the wheel offset, you need to measure dimension “B” on the inside of the wheel. Divide size “X” in half. Subtract size X/2 from size “B”. If the difference is positive, then the offset is positive; if it is negative, then the offset is “negative”. Or, in other words: The offset is “positive” if the mating plane does not go beyond the imaginary plane. The offset is “negative” if the mating plane passes through an imaginary plane. | ||
Disc rim flanges, side flanges.
6.5J×15 H2 5/112 ET39 d57.1 - “type J rim flange”
J (JJ, JK, K,B, P, D...) This letter encodes technical information about the disc rim flanges (design, shape, height). The most common types of disks today are J (mainly for single-wheel drive vehicles), and JJ (usually for all-wheel drive). The flanges of the rim of the rim affect the installation of rubber, compensating weights, as well as the resistance to displacement of the tire on the rim in extreme conditions. Obviously, despite the external interchangeability of, for example, J and JJ disks, it is still better to choose the parameter recommended by the car manufacturer.
Wheel rim and champa shelves.
6.5J×15 H2 5/112 ET39 d57.1 - “shelves rims and humps type H2”
H (H2, FH, AH, CH...) – these letters encrypt information about the design features of the disk rim flanges and the protrusions (hamps) on them. Humps are designed for tubeless tires and ensure correct installation of the tire on the rim. Some tires require special wheel parameters in this regard; this point needs to be clarified when purchasing tires. In general, a car enthusiast does not need to delve deeply into the essence of these designations.
Other possible designations.
The disk may also indicate:
- Date of manufacture . Usually a year and a week. For example: 0504 means the disc was released in week 5 of 2004.
- SAE, ISO, TUV, PCT... - the mark of the regulatory body. The marking indicates that the wheels comply with international rules or standards.
- MAX LOAD 2000lb - a very common designation for the maximum load on a wheel (denoted in units of mass - kilograms or pounds). The maximum load listed here is 2000 lbs (908 kg).
- MAX PSI 50 COLD - means that the tire pressure should not exceed 50 psi (3.5 kgf / sq. cm), the word COLD (cold) means that the pressure should be measured when the tire is cold.
- Other
Wheel mount. The procedure for tightening bolts (nuts).
When installing the wheel, tighten the fastening elements in the order shown in the diagram:
| 4 holes | 5 holes | 6 holes |
Recommended tightening torque depending on the diameter of the wheel mounting thread:
| 10 mm | 60 Nm | 6 kg*m |
| 12 mm | 90 Nm | 9 kg*m |
| 14 mm | 110 Nm | 11 kg*m |
| 7/16 inches | 80 Nm | 8 kg*m |
| 1/2 inch | 90 Nm | 9 kg*m |
Rubber wheel for a passenger car. Matching rubber tires or wheels for one car model.
Is it possible to install components with a large central hole?
Is it possible to install designs with a large CO?
The question of what effect CO has on car rims remains relevant both among beginners and experienced drivers. The disc, which has a universal central diameter, is sold in all stores, as well as online resources. Modern designs that have a large central hole fit many models.
The main reason why original automobile developments are noticeably more expensive than even the highest quality non-original analogs is the requirements of automakers.
What is a central heating center on car wheels?
What does CO mean?
Many people are interested in the question of what the central hole of the disk is. This indicator determines many parameters. The vehicle's handling on icy/wet asphalt depends on this value. When choosing wheels for a car, DIA is defined as a characteristic of the wheel. Sometimes manufacturers may designate this indicator as D. Some car owners buy large mounting bolts that are not installed on the structure. All these nuances should be taken into account to ensure the safety of the driver/passenger.
American tire markings
American tire manufacturers have their own markings. There are two types of markings: The first is very similar to the European one, only the letters “ P ” (Passanger - for a passenger car) or “ LT ” (Light Truck) are placed in front of the standard size. For example: P 195/55 R 14 or LT 235/65 R 15. And other markings, which are fundamentally different from the European ones. For example: 31x10.5 R15 31 - outer diameter of the tire in inches. 10.5 - tire width in inches. 3 R - radial tire. 15 is the inner diameter of the tire in inches. Additional designations used by tire manufacturers
- M&S (Mud + Snow - mud plus snow). This means that these tires are specifically designed as winter or all-season tires.
- M/T (Mud Terrain) - mud landscapes.
- A/T (All Terrain) - all-season tires.
- AS - All Season - all-season
- Any Season is an all-season tire.
- R+W (Road + Winter) - all-season tire.
- All Season is an all-season tire designed for year-round use.
- Rotation - sports tires with a directional tread pattern have an arrow on the sidewall of the tire indicating the required direction of rotation of the tire.
- Outside and Inside (or Side Facing Out and Side Facing Inwards ) are asymmetrical tires, when installing which you must strictly follow the rule for installing the tire on the rim. The inscription Outside (outside) should be on the outside of the car, and Inside (inside) - on the inside.
- Left or Right - means that the tires of this model are left and right. When installing them, you must strictly follow the rule for installing the tire on the car: left ones only on the left, and right ones, accordingly, only on the right.
- Steel Radial - radial tire with metal cord
- Tubeless (TL) - tubeless tire. If this inscription is not present, then the tire can only be used with a tube.
- Tube Type (TT)—the tire must be used with a tube.
- MAX PRESSURE - maximum permissible tire pressure, in kPa.
- RAIN , WATER , AQUA (or umbrella pictogram) - means that these tires are specially designed for rainy weather and have a high degree of protection against aquaplaning.
- Treadwear 380 - wear resistance coefficient, determined in relation to the “base tire”, for which it is equal to 100. The wear indicator is a theoretical value and cannot be directly related to the practical life of the tire, which is significantly influenced by road conditions, driving style, compliance pressure recommendations, adjusting car wheel alignment angles and wheel rotation. The wear indicator is presented as a number from 60 to 620 with an interval of 20 units. The higher its value, the longer the protector will withstand when tested according to the established methodology.
- Traction A - coefficient of adhesion, has values A, B, C. Coefficient A has the largest amount of adhesion in its class.
- Max Load - maximum load and then the values are in kilograms and pounds.
- PR (Ply Rating) - the strength (bearing capacity) of the frame is conditionally assessed by the so-called ply rate. The stronger the carcass, the more air pressure the tire can withstand and, therefore, have a greater load capacity. For passenger cars, tires with a ply rating of 4PR and sometimes 6PR are used, and in this case the latter are labeled “Reinforced”, i.e. “reinforced” (tires with increased load capacity).
- Extra Load (XL) - increased load index.
- Reinforced (Reinf or RF) - increased load index.
- On light trucks and minibuses, the most common tires are 6PR and 8PR. The increased ply (i.e. strength) of the tire can be indicated by the letter “ C ” (commercial), which is placed after the designation of the bore diameter (for example, 185R14C)
- TWI - the sign is located on the sidewall of the tire and shows the location of the remaining tread height marks in the main grooves. For the countries of the European Union and the Russian Federation, the remaining tread height of a worn passenger tire must be at least 1.6 mm.
- ZP - zero pressure (Zéro Pression), Michelin's commercial designation for tires with reinforced sidewalls. ZP: Possibility to continue driving in case of a puncture for a distance of up to 80 km at a speed of up to 80 km/h. ZP SR: Possibility to continue driving in case of a puncture for a distance of up to 30 km at speeds of up to 80 km/h.
- SST - Self Supporting Tires. These tires can carry the load and continue driving after a puncture.
- Dunlop MFS (Maximum Flange Sheild) - The Maximum Bead Rim Protection system protects expensive wheels from damage to curbs and sidewalks - a rubber profile around the circumference of the tire, located on the lower part of the wall above the rim flange, forms a buffer zone.
- Studless - does not suit the studded fabric.
- Studdable - subject to studding. In addition, quality standards are indicated on the tires (the letter “E” in a circle is the European standard, “DOT” is the American standard).
Table of correspondence between tire size and rim width and diameter
| For passenger cars | ||
| Disc diameter (inches) | Tire size | Rim width (inches) |
| Profile height 80 | ||
| 13 | 135/80R13 | 3,5 |
| 145/80R13 | 4 | |
| 155/80R13 | 4,5 | |
| 165/80R13 | 4,5 | |
| 165R13 | 5 | |
| 14 | 175/80R14 | 5 |
| 185/80R14 | 5 | |
| Profile height 70 | ||
| 13 | 135/70R13 | 4 |
| 145/70R13 | 4,5 | |
| 155/70R13 | 4,5 | |
| 165/70R13 | 5 | |
| 175/70R13 | 5 | |
| 185/70R13 | 5,5 | |
| 14 | 165/70R14 | 5 |
| 175/70R14 | 5 | |
| 185/70R14 | 5,5 | |
| 195/70R14 | 6 | |
| Profile height 65 | ||
| 13 | 155/65R13 | 4,5 |
| 165/65R13 | 5 | |
| 175/65R13 | 5 | |
| 14 | 155/65R14 | 4,5 |
| 165/65R14 | 5 | |
| 175/65R14 | 5 | |
| 185/65R14 | 5,5 | |
| 195/65R14 | 6 | |
| 15 | 145/65R15 | 4,5 |
| 155/65R15 | 4,5 | |
| 165/65R15 | 5 | |
| 175/65R15 | 5 | |
| 185/65R15 | 5,5 | |
| 195/65R15 | 6 | |
| 205/65R15 | 6 | |
| 215/65R15 | 6,5 | |
| 16 | 215/65R16 | 6,5 |
| 17 | 235/65R17 | 7 |
| 18 | 235/65R18 | 7 |
| Profile height 60 | ||
| 14 | 165/60R14 | 5 |
| 175/60R14 | 5 | |
| 185/60R14 | 5,5 | |
| 195/60R14 | 6 | |
| 15 | 175/60R15 | 5 |
| 185/60R15 | 5,5 | |
| 195/60R15 | 6 | |
| 205/60R15 | 6 | |
| 225/60R15 | 6,5 | |
| 16 | 205/60R16 | 6 |
| 215/60R16 | 6,5 | |
| 225/60R16 | 6,5 | |
| 235/60R16 | 7 | |
| 17 | 225/60R17 | 6,5 |
| Profile height 55 | ||
| 14 | 185/55R14 | 6 |
| 15 | 175/55R15 | 5,5 |
| 185/55R15 | 6 | |
| 195/55R15 | 6 | |
| 205/55R15 | 6,5 | |
| 225/55R15 | 7 | |
| 16 | 195/55R16 | 6 |
| 205/55R16 | 6,5 | |
| 215/55R16 | 7 | |
| 225/55R16 | 7 | |
| 245/55R16 | 7,5 | |
| 17 | 205/55R17 | 6,5 |
| 215/55R17 | 7 | |
| 225/55R17 | 7 | |
| 235/55R17 | 7,5 | |
| 245/55R17 | 7,5 | |
| 255/55R17 | 8 | |
| Profile height 50 | ||
| 15 | 195/50R15 | 6 |
| 205/50R15 | 6,5 | |
| 225/50R15 | 7 | |
| 16 | 185/50R16 | 6 |
| 195/50R16 | 6 | |
| 205/50R16 | 6,5 | |
| 215/50R16 | 7 | |
| 225/50R16 | 7 | |
| 235/50R16 | 7,5 | |
| 245/50R16 | 7,5 | |
| 255/50R16 | 8 | |
| 17 | 205/50R17 | 6,5 |
| 215/50R17 | 7 | |
| 225/50R17 | 7 | |
| 235/50R17 | 7,5 | |
| 18 | 235/50R18 | 7,5 |
| 245/50R18 | 7,5 | |
| 19 | 275/50R19 | 8,5 |
| Profile height 45 | ||
| 15 | 195/45R15 | 6,5 |
| 16 | 195/45R16 | 6,5 |
| 205/45R16 | 7 | |
| 215/45R16 | 7 | |
| 225/45R16 | 7,5 | |
| 245/45R16 | 8 | |
| 17 | 205/45R17 | 7 |
| 215/45R17 | 7 | |
| 225/45R17 | 7,5 | |
| 235/45R17 | 8 | |
| 245/45R17 | 8 | |
| 255/45R17 | 8,5 | |
| 18 | 215/45R18 | 7 |
| 225/45R18 | 7,5 | |
| 235/45R18 | 8 | |
| 245/45R18 | 8 | |
| 255/45R18 | 8,5 | |
| 275/45R18 | 9 | |
| 19 | 245/45R19 | 8 |
| 20 | 275/45R20 | 9 |
| Profile height 40 | ||
| 16 | 215/40R16 | 7,5 |
| 17 | 205/40R17 | 7,5 |
| 215/40R17 | 7,5 | |
| 235/40R17 | 8,5 | |
| 245/40R17 | 8,5 | |
| 255/40R17 | 9 | |
| 265/40R17 | 9,5 | |
| 275/40R17 | 9,5 | |
| 285/40R17 | 10 | |
| 18 | 205/40R18 | 7,5 |
| 225/40R18 | 8 | |
| 235/40R18 | 8,5 | |
| 245/40R18 | 8,5 | |
| 255/40R18 | 9 | |
| 265/40R18 | 9,5 | |
| 275/40R18 | 9,5 | |
| 285/40R18 | 10 | |
| 19 | 225/40R19 | 8 |
| 245/40R19 | 8,5 | |
| 255/40R19 | 9 | |
| 275/40R19 | 9,5 | |
| 20 | 245/40R20 | 8,5 |
| Profile height 35 | ||
| 17 | 225/35R17 | 8 |
| 265/35R17 | 9,5 | |
| 335/35R17 | 12 | |
| 18 | 215/35R18 | 7,5 |
| 225/35R18 | 8 | |
| 235/35R18 | 8,5 | |
| 255/35R18 | 9 | |
| 265/35R18 | 9,5 | |
| 275/35R18 | 9,5 | |
| 285/35R18 | 10 | |
| 295/35R18 | 10,5 | |
| 345/35R18 | 12 | |
| 19 | 225/35R19 | 8 |
| 235/35R19 | 8,5 | |
| 245/35R19 | 8,5 | |
| 255/35R19 | 9 | |
| 265/35R19 | 9,5 | |
| 275/35R19 | 9,5 | |
| 285/35R19 | 10 | |
| 295/35R19 | 10,5 | |
| 20 | 245/35R20 | 8,5 |
| 255/35R20 | 9 | |
| 275/35R20 | 9,5 | |
| 21 | 245/35R21 | 8,5 |
| 255/35R21 | 9 | |
| Profile height 30 | ||
| 18 | 285/30R18 | 10 |
| 295/30R18 | 10,5 | |
| 315/30R18 | 11 | |
| 335/30R18 | 12 | |
| 345/30R18 | 12 | |
| 19 | 265/30R19 | 9,5 |
| 275/30R19 | 9,5 | |
| 285/30R19 | 10 | |
| 295/30R19 | 10,5 | |
| 305/30R19 | 11 | |
| 345/30R19 | 12 | |
| 20 | 235/30R20 | 8,5 |
| 245/30R20 | 8,5 | |
| 255/30R20 | 9 | |
| 285/30R20 | 10 | |
| 335/30R20 | 12 | |
| 21 | 255/30R21 | 9 |
| 285/30R21 | 10 | |
| 295/30R21 | 10,5 | |
| 22 | 255/30R22 | 9 |
| Profile height 25 | ||
| 19 | 315/25R19 | 11,5 |
| 20 | 285/25R20 | 10,5 |
| 295/25R20 | 10,5 | |
| 325/25R20 | 12 | |
| 21 | 295/25R21 | 10,5 |
| 22 | 295/25R22 | 10,5 |
What to do if the CO of the structure is greater than the CO of the hub
Difference in CO size
The diameter of the central hole of the disk must match the parameters of the diameter of the landing cylinder where the hub is located. In recent years, many manufacturers have begun to produce identical designs for several car brands at once. Therefore, when purchasing new components for a vehicle, you need to determine the compliance of this parameter.
