All disks are divided into two large groups: alloy wheels and steel wheels.
Steel disks, or rather, their parts, are stamped from a sheet, and then these parts are joined by welding. It turns out to be extremely cheap and quite high quality - which is why the vast majority of cars on the factory assembly line are equipped with steel ones. Their advantages include fairly high strength and the possibility of recovery even in the event of very strong crushing of the edges. The main disadvantages: large mass, low manufacturing accuracy (which means there may be problems with balancing) and outdated design.

Alloy wheels It has many properties better than steel. They allow any games with design, alloy wheels the highest manufacturing precision, they perfectly remove heat from the brake unit, but most importantly - they are light (the lighter alloy wheel, the lower the total mass of the unsprung parts of the car, and therefore the better). These are general advantages. It is more precise to judge the pros and cons alloy wheels it is possible, only taking into account in what way and from what particular alloy they are made - there are many nuances here, the wheel is different.

By manufacturing method alloy wheels divided into cast and forged. A cast disc has a granular internal structure of the metal, and this is its main disadvantage: when driving for a long time over potholes, the metal begins to accumulate microcracks (invisible and therefore dangerous), which will sooner or later manifest themselves - the disc can split from a strong impact. Forged metal, the metal of which has a multilayer fibrous structure, is extremely durable; It is not afraid of potholes, it will not crack under any conditions (forging provides the necessary ductility). It is theoretically possible to dent it, but the suspension will more likely fall apart than the edge of a forged wheel will dent.

Discs are cast and forged from aluminum and magnesium alloys. If you place alloy wheels in order "from minus to plus" purely technical parameters, then the series will be as follows: cast magnesium (light, but capricious, cracks quickly), cast aluminum (normal in terms of the totality of qualities), forged aluminum (strong and lightweight) and forged magnesium (super strong and lightweight). But when choosing disks, it is clear that not only technical parameters play a role. We advise you to immediately discard extremes: magnesium wheels, both cast and forged, are very rare; as a rule, they are made only to order for sports cars.
The price of magnesium ones can go over $1000 (piece).

Wheel rim markings

The wheel rim markings must include the following: manufacturer's trademark, date of manufacture (week and year), heat number, permissible static load (kg or lb), stamp of the inspection body, separate X-ray inspection stamp (usually for cast ones) and, of course, standard size For example, 5.5Jx15H2 ET30 - what does this mean?

5.5 is the rim width in inches. Standard range: 3.5; 4.0; 4.5; 5.0; 5.5; 6.0; 6.5 and 7.0 inches; Tuning, sports and off-road cars can have wider wheels.

15 is the mounting diameter of the rim in inches. Standard range for cars and SUVs: 10, 12, 13, 14, 15, 16, 17, 18 and 19 inches.

J and H2 are symbols needed more by specialists. J encrypts information about the design of the rim flanges (can be JJ, JK, K or L). And H2 is the design code for humps - ring-shaped protrusions on the rim flanges that serve to securely hold the tubeless tire on the rim (there are many variations: H, FH, AH...).

ET30 - wheel offset in millimeters. May be designated as OFFSET or DEPORT. This is the distance between the longitudinal plane of symmetry of the rim and the mounting (fitting) plane of the wheel (if these planes coincide, the offset is zero). You cannot take wheels with an offset that is not standard for your car. Reducing the offset (the wheel track becomes wider) can create additional stress on the wheel bearings and suspension. With an increased reach (the track narrows) alloy wheel may stick into the brake assembly. In general, all games with crashes are a delicate matter. On tuning and sports modifications it is changed, but this is done in conjunction with a number of other changes.

The diameter of the mounting holes is PCD (Pitch Circle Diameter). For example, PCD100/4 means that this diameter is 100 mm, and the number of holes is 4 (this, however, can be seen as such).

Besides, alloy wheel they are selected according to the diameter of the central hole (if the error is minus, you will not be able to put the wheel on the car) and according to the characteristics of the mounting holes: tightening the bolts (nuts) “on a plane”, “on a sphere” or “on a cone” - you can’t go wrong with this.

A wheel rim is one of the components of a car wheel. It serves as the basis for fastening, 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 rims, such as their diameter, width and other indicators, determine the choice in favor of one option or another.

Purpose and design of wheel rims

Car wheel design

Wheel rims, in addition to improving appearance Wheels are also a necessary element for moving a car on the road. The tire itself is put on them directly. A disk with a tire on it is a car wheel mounted on a hub.

The tire is fixed on the rim by an annular ledge. The tire bead is located on a shelf that has three dimensions: standard, flat and widened. The tire is usually seated on the outer shelf. The shelf smoothly transitions into the side, which has a different profile shape.

The main purpose of the wheel rim is to ensure the correct fit of the tire and its efficient work while driving. That is why the main requirements for a disk are strength and rigidity. Also, the disk must have a relatively small mass and geometric parameters specified by the manufacturer. This is due to the fact that wheels, as unsprung mass, influence the vehicle's driving dynamics and its handling.

Types of rims

Types of rims

Depending on the material of manufacture and production technology, there is the following classification of wheel rims:

• stamped;
• cast;
• forged;
• compound.

Stamped or steel wheels

They are considered the simplest and most accessible. Structurally, they are stamped steel parts welded to each other.

Pros of this type:

1. Reasonable price.
2. Relatively high strength.
3. Possibility of recovery even in the event of a strong blow.

The disadvantages include:

1. Unpretentious design.
2. Large mass.
3. Low resistance to corrosion.

Alloy wheels

Alloy wheels (sometimes called alloy wheels) are made from aluminum or magnesium alloys. These discs have high strength and good . In addition, they have a beautiful appearance. If in a steel wheel the disk itself is connected to the rim by welding, then an alloy wheel is a single product.

Alloy wheel on a car

The general advantages of alloy wheels include:

1. High manufacturing precision.
2. Various disc design options.
3. Ease.
4. They remove heat well from the brake mechanisms.

Among the disadvantages of a cast disc, one can note its relative fragility. Such a disk has a granular internal metal structure that does not resist impacts well. As you move over uneven surfaces, microcracks accumulate, as a result of which the disc may sooner or later crack. Another option is to increase the wall thickness, which will lead to weight gain. It is also expensive and difficult to restore.

In addition, this type of disc needs surface protection. Otherwise, the casting will lose its presentation.

Forged wheels

Composite disks

Further improvements in cast wheels led to the development of forged wheels or "forging". This type is produced by stamping aluminum alloys with the addition of magnesium and titanium and subsequent mechanical processing. This provides a fibrous disc structure consisting of several layers. As a result, the product is characterized by high strength, low weight and resistance to shock loads.

The main disadvantage of forging is the high price.

Combined or composite discs

This type of wheel combines "forging" strength with a "cast" design. The product is based on a cast construction with forged rims bolted on. The high cost of disks outweighs many of their advantages.

Wheel parameters

Basic parameters of wheel rims

Wheel rims are characterized by the following parameters:

• rim width (distance between shelves);
• disk diameter;
• disc ejection;
• the number of holes for fastening and the diameter of their location;
• diameter of the central hole of the disk.

Rim width

The width of the rim should be 25-30% less than the width of the tire profile. The use of too wide (as well as too narrow) disks is undesirable. Due to violation of the design profile of the tire, the driving characteristics of the car deteriorate.

The permissible deviation from the norm in the distance between the shelves is 0.5-1.0 inches for disks with a diameter of up to 14 inches and 1-1.5 inches for disks with a diameter of more than 15 inches.

Disc diameter

The mounting diameter of the wheel or the size of the wheel rim for the tire is measured at the level of the shelves. There is a range of disc sizes ranging from 10 to 22 inches in diameter. The most common are its average values: from 13 to 16 inches.

Disc offset

The overhang of the disk or its protrusion is the distance from the vertical axis of symmetry of the disk to the mating plane of contact with the wheel hub.

The disc overhang can be zero or positive when the disc hub protrudes outward relative to the axis of symmetry of the disc. In the case in which the hub is recessed relative to the middle of the disk, the offset will be negative.

The amount of overhang is expressed in millimeters and is designated as ET. With positive overhang, the maximum ET value is 30 mm. In the case of a negative offset, the critical value of ET will also be 30 mm, but with a negative sign.

This indicator must comply with the vehicle manufacturer's instructions. Otherwise, the vehicle's handling may change for the worse, and the life of the suspension and transmission elements (drive shafts, hubs, etc.) may also decrease. This occurs because a change in offset entails a change in the leverage of forces and moments applied to the wheel during movement. Also, depending on the offset, it may change, which has a negative effect when braking.

Diameter of mounting holes and their number

This indicator is designated PCD. The first number in the indicator indicates the diameter of the holes, and the second – their number.

Standard diameter values ​​are considered to be from 98 to 140 mm, and the number of holes ranges from 4 to 6.

It is very difficult to determine by eye the size of the disc and the hub. And installing a disk of the wrong diameter can cause the wheel to skew, which will lead to its “beating”.

Disc center hole diameter

The diameter of the central or mounting hole of the disk ranges from 50 to 70 mm. Accuracy in matching the disc to the hub is very important. But this applies to the standard wheels of the car. Spare parts manufacturers often make a hole with a slightly larger diameter, and offer a set of adapter rings complete with the disc. In this case, the wheels will be centered on the PCD.

Decoding disk markings

Disc markings

The marking of the disk characterizes its size. It is usually applied to the inside of the hub of a cast disk. Let's imagine the designation of each of the indicators with the following example: 5.0×16″ 4×113 ET28 d58.4, Where

• 5.0 – rim width in inches;
• 16″ – disk diameter in inches;
• 4×113 – number of mounting holes and their diameter;
• ET28 – disc offset;
• d58.4 – diameter of the central hole.

Conclusion

When choosing rims, you need to consider how they are technical specifications(such as diameter, disc width and other indicators), as well as the quality and origin of the discs themselves. Otherwise, the purchase depends on the preferences of the car enthusiast and his willingness to part with a certain amount when purchasing wheels.

Wheels play a huge role in determining the appearance of a car. Therefore, car owners are very careful when choosing a wheel design.

In addition to aesthetic value, discs perform a lot of other functions. The wheel connects the car to the road, ensuring its movement. It also perceives all irregularities and changes in the road profile that are transmitted through the tire.

Properly selected rims mean road safety, reduced fuel consumption, increased transmission service life, and excellent design.

Wheels can be classified according to the following criteria:

1. according to manufacturing technology:
   • steel
   • light alloy(cast and forged)
2. by design:
   • non-separable
   • collapsible(one-, two-, three-component)
     these are disks in which the structure of the entire disk or just its rim consists of several elements
3. by applicability:
   • for tube tires
     Their characteristic feature is the disassembly of the structure and the design of the seats for the tire. The air valve of the chamber is discharged through a hole in the disk. The landing flanges of the disk are flat and have an angle of inclination to the horizon (at an angle to the axis of rotation of the disk) of 5°.
   • for tubeless tires
     These discs have a sealed design. The air valve is fixed directly to the disk. The rim shape of this disk has inclined landing shelves (hamps), located generally at an angle of 15° to the horizontal. Basically, the design of rims for tubeless tires is not collapsible, however, there are options for a collapsible design.

Steel wheels

Nowadays, steel wheels are the most widely used. They consist of two parts - a rim and a “plate” of a special profile (for rigidity), made by stamping a steel sheet and connected to each other by spot welding. Most cars are equipped with steel wheels at the manufacturing plants.

• advantages:
  1. low price;
  2. the possibility of recovery after damage, since such disks do not burst upon impact, but are crushed;
  3. If a car wheel is subjected to an impact load, then the steel plastic disc, deforming, takes on a significant part of the impact energy, while the suspension and steering parts receive minimal damage.
• flaws:
  1. heavy weight;
  2. a small number of designs;
  3. low corrosion resistance due to the quality of the coating (the lowest corrosion resistance is for disks coated with enamel and electrophoresis);
  4. Ride comfort, braking dynamics and vehicle handling are lower than those of cast alloy wheels.

Alloy wheels

Made from aluminum and magnesium based alloys by casting or forging. In many properties they are better than steel. The main purpose of an alloy wheel is to increase the attractiveness of the car. Also, alloy wheels reduce wheel weight, and reducing the weight of unsprung parts (which includes wheels) improves ride quality, increases driving safety and reduces wear on suspension parts. Having an ideal geometry, with good balancing, unpleasant vibrations are completely eliminated.

Discs are cast and forged from aluminum and magnesium alloys. If you arrange alloy wheels in order “from minus to plus” according to purely technical parameters, then the row will be as follows: 1 - cast magnesium wheel (light, but capricious, cracks quickly), 2 - cast aluminum disk (normal in terms of the totality of qualities), 3 - forged aluminum disc (strong and lightweight) and 4 - forged magnesium disc (super strong and lightweight).

Alloy wheels

Cast aluminum alloy wheels are approximately 15-30% lighter than steel (depending on design). In addition, the appearance of alloy wheels is quite attractive; casting technology allows them to be manufactured in almost any design. Cast discs, although lightweight, are less durable than steel ones. And most importantly, they are much less plastic, and under heavy loads they do not deform, but simply collapse. Cast wheels made from magnesium-based alloys are even lighter than aluminum wheels (magnesium is less dense than aluminum), but magnesium is much less resistant to corrosion, so multi-layer protective coatings must be applied to magnesium wheels.

• advantages:
  1. availability of a huge number of designs;
  2. the low weight of alloy wheels provides serious advantages: a reduction in the weight of the unsprung parts of the car, due to which, when driving on uneven roads, less impact loads are applied to the body, which means that the operational property of the car, such as smoothness, is improved; suspension operating conditions are improved: elastic and damping elements absorb less load, thereby increasing their service life; lightweight wheels quickly restore contact with the road surface when hitting an obstacle, which increases the stability and controllability of the car at high speeds; reducing wheel weight has a positive effect on vehicle dynamics, since acceleration and braking of a less inertial wheel requires less force, which ultimately leads to an increase in the service life of the engine, transmission and braking system, as well as to a decrease in fuel consumption.
• flaws:
  1. fragility (a cast disk has a granular internal structure of the metal: when driving for a long time over potholes in the metal, there is a process of accumulation of microcracks (invisible and therefore dangerous), which sooner or later will manifest themselves - the disk can crack from a strong impact);
  2. surface protection is required, since without this the disc quickly becomes covered with a whitish oxide film and loses its presentation.

Forged wheels

In Russia, for the production of forged wheels, the technology of hot die forging in closed dies is used (hot die forging is a technological operation in which the workpiece is deformed in a special tool - a die). In other countries, the rolling method (cold forming) is used. Fundamentally, these are two different processes, but the translation of their names into Russian means “forged,” which is reflected in the names of the products. Taking into account the specified design features, at the design stage of a forged wheel, a die base is obtained, and then a stamp. The wheel manufacturing technology is very complex. The workpiece is subjected to step-by-step stamping with intermediate heating before each deformation. To obtain the necessary structure of a light alloy and use all its properties, presses are used that develop a force of 6 to 20 thousand tons. The weight of dies can reach 10 tons. Only with this technology and the use of the most ductile alloy will the workpiece have the necessary fibrous structure, which makes it possible, during subsequent machining, to make a forged wheel lighter than a cast one. The initial weight of the workpiece is about 20 kg (for a 6.5x15" wheel after machining it is reduced by more than three times. The previous stages, that is, the design of the wheel, die base, and production of dies, provide for all turning, milling and boring operations without cutting the longitudinal fibers of the structure alloy. To reduce production costs, some factories use the technology of stamping windows. The dimensions of the future wheel, the maximum possible number of mounting holes, and the maximum offset are initially included in the stamped blank.

A forged disc, the metal of which has a multilayer fibrous structure, is extremely durable. A forged disc can withstand the strongest impacts; in extreme cases, it does not burst like a cast one, but bends without cracking, which is certainly safer. It is theoretically possible to dent it, but the suspension will more likely fall apart than the edge of a forged wheel will dent.

• advantages:
  1. high strength and rigidity of the structure;
  2. the weight of a forged disk is 30-50% less than the weight of a steel one and 20-30% less than a similar cast one;
  3. high corrosion resistance.
• flaws:
  1. high price caused by high-tech production;
  2. small selection of designs;
  3. In the event of a collision with a serious obstacle, the tire may be cut.

In recent decades, stamped steel wheel rims have been widely replaced by cast models. Some car enthusiasts do this to improve the appearance of their cars, but for most of them, not only the aesthetic effect is important, but also improved performance.

So what are they alloy wheels and what are their advantages over stamped ones?

What are alloy wheels?

As is easy to understand from the name, alloy wheels are products made by casting. Steel is not suitable for them for a number of reasons, so mainly aluminum alloys are used for disks, and sometimes more exotic magnesium-based alloys.

The finished disk is a solid casting, which, to acquire greater strength, is subjected to a hardening procedure that relieves residual stresses in the metal. After these technological operations, the surface of the disc is polished and coated with a special varnish to maintain a stable shine.

The shape of the disc is the result of painstaking calculations by leading engineers of the largest automobile companies. The composition of the alloy and the technology for its preparation from the most famous manufacturers are often practically impossible to copy. That is why, despite their external similarity, discs produced under global brands are much more reliable and durable than their cheap Chinese copies.

Advantages of alloy wheels

When deciding to replace stamped steel wheels with light-alloy cast ones, every car owner must understand why he is doing this and what he will get as a result of the replacement.

So, what are the advantages of cast wheels compared to stamped ones?

1. Light weight. Aluminum alloy wheels, moreover, in the absence of caps, weigh much less than their stamped predecessors - sometimes the weight reduction reaches 50% of the previous one. As a result, the load is reduced and the car becomes more controllable, stable and obedient on the road. In addition, ride comfort increases as the suspension absorbs shocks and shocks more effectively. An important factor is the reduction in wear of the suspension, as a result of which the costs of maintaining it in good technical condition are reduced.

2. Openness of the braking system. Due to the absence of caps, the inside of the wheel remains open during movement and is cooled naturally. This improves the performance of the braking system, providing it with greater reliability and reliability.

3. Corrosion resistance. Unlike steel, which easily rusts, aluminum alloys are resistant to corrosion even when the outer varnish is deeply scratched.

4. Excellent design. The wheel hubs form an elegant pattern, individual for each model. Well-chosen wheels can significantly improve the appearance of a car, give it individuality and enhance the advantages of body design.

Disadvantages of alloy wheels

As happens everywhere, the disadvantages inherent in solid wheels are a continuation of their advantages. Thus, the strength obtained through hardening turns into fragility: with a strong impact, the cast disk does not bend, but bursts. In this case, it is impossible to continue driving, and if there is no spare wheel in the trunk, the only option is to call a tow truck. A burst disk cannot be repaired - it only needs to be replaced with a new one.

The variety of disc designs can also lead to problems: if you need to replace one disc, it can be difficult to find one that is identical in size and design. True, today the task is made easier by online trading, thanks to which disks of the desired shape can be found and ordered even on the opposite side of the planet.

The exposed spokes and rim that adorn the car require constant washing and cleaning, as road dust and dirt constantly penetrate into the recesses. If you don't pay attention to cleaning, accumulated dirt can cause wheel imbalance, which leads to uneven wear and premature failure of suspension components.

Car wheels can be steel or alloy. Alloy wheels are divided according to materials into aluminum and magnesium, and according to manufacturing technology - into cast and forged.

Steel wheels

The least expensive, and therefore the most common, are steel wheels. They are made of sheet steel, and their design consists of a rim and a “plate” welded to it. To prevent corrosion, the outer surface of steel disks is coated with enamel, chrome, electrophoresis (cataphoresis) coating or a special powder layer. This type of disc is usually used to equip production cars coming off assembly lines all over the world.

Advantages:

• low cost;
• the ability not to burst or crumble upon impact. Due to their plasticity, discs wrinkle, and therefore it is possible to restore them for little money.

Flaws:

• significant weight;
• reduced corrosion resistance due to unreliable coating;
• limited design options.

Cast aluminum wheels

Manufactured by casting from light alloys based on aluminum.

Advantages:

• 20-30% lighter than steel. This reduces the unsprung mass of the vehicle and leads to improved ride quality, acceleration dynamics and reduced fuel consumption of the vehicle.
• increased resistance to environmental influences due to the formation of an oxide film on their surface.

Flaws:

• recovery from deformation is very expensive (comparable in cost to replacing a disk);
• reduce the service life of the suspension, since due to less crushing, alloy wheels do not absorb shock impacts, but transfer them to the suspension.

The best imported wheels have a higher price compared to domestic ones, but, as a rule, they consist of balanced alloys and have less weight and greater impact strength.

Cast magnesium wheels

Manufactured by casting from light alloys based on magnesium.

Advantages:

• superior to aluminum in impact strength;
• have less own weight.

Flaws:

extremely low corrosion resistance. Not suitable for Russian city roads sprinkled with chloride compounds, as they quickly become covered with unaesthetic stains.

Forged wheels

They, like cast ones, are made from magnesium or aluminum alloys. However, such discs differ in the manufacturing method: it is hot stamping followed by thermal and/or mechanical treatment.

Advantages:

• high corrosion resistance, no need for additional coating;
• high strength and rigidity of the structure. When hit, the forged disc does not crack, but only crumples (in this case, the impact must be very strong);
• the lightest of all types of disks (1.2-2 times lighter than steel).

Flaws:

• high cost.
• size restrictions.

Most likely, the future belongs to forged wheels, since their performance is superior to steel and cast wheels. Already in the near future, we can predict an active growth in demand for them, since domestic manufacturers have already begun their production and are producing quite acceptable (based on the price/quality ratio) products.

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