How to choose the right wheels for your car

How to choose wheels for a car

If the factory wheels are worn out, then the driver needs to know how to select wheels. The stores offer a wide range of products, it is easy to get lost in such a choice. But there are basic criteria that must be adhered to.

Important parameters

There are six main parameters, and you need to focus on them. Every driver must know them:

diameter of the disk itself;

the width of its rim;

diameter of fastener holes;

departure;

diameter of the central hole;

disk type.

Discs with a diameter of 13-16 inches are popular. But if the driver wants to use low tires, then he chooses large products. It is important to know: their size and mass are related. The larger the disc, the more the driving performance of the car changes.

The width of the rim is usually less than that of the tire, by about 30%. A disc that is too large or too narrow can reduce the ride quality of the vehicle. Each product is marked PCD - the diameter of the mounting holes. You need to pay attention to it, because it also means the distance between them. If you purchase the wrong products, the bolts will be undertightened or overtightened. This should be remembered by those drivers who do not know how to choose the right wheels for their car.

Wheel offset is calculated taking into account stability, controllability and bearing load. This indicator can be positive, zero and negative. The diameter of the central hole is related to the hub. In production conditions, wheels are marked precisely according to this indicator. But some manufacturers produce wheels with a larger diameter and a set of adapters. This allows you to make a universal product from almost any disk.

There are several types of discs on the market. They differ in the materials used to make them. The more expensive the metal, the higher the cost of the products. This is important to consider before choosing wheels.

Types of rims

The material determines which wheel rim to choose for your car. There are only three main types of products:

stamped;

cast;

forged.

It is better to learn about the features of each type before choosing discs.

The cheapest discs are stamped. They are used to complete inexpensive cars. Typically, such products have plastic caps that are not durable. The discs themselves are made of steel and covered with enamel on top.

In addition to their low price, they have another advantage - they are easy to repair. In case of impact or other mechanical damage, stamped discs bend rather than break. They are easy to straighten to their original position. But the products also have several disadvantages. They weigh a lot, which affects the ride of the car. And you won’t be able to choose wheels with an interesting design. Manufacturers think only about their functionality - all products look almost the same.

Cast products are no less popular than stamped ones. But they are made not from heavy steel, but from aluminum alloys. This material is lighter. Special technologies make it possible to produce discs of any shape and size. It is precisely because of their design and low weight that they are so popular among car owners.

Although they also have significant drawbacks. Since aluminum is a light and fragile material, when impacted, the discs crack and break, rather than crumple. It is impossible to repair such a product; you will only have to buy a new one. And it costs more than a stamped one.

A better option is forged wheels. They are produced using an expensive procedure - volumetric hot stamping. Thanks to this, the internal structure of the metal is dense. And although the mass of such products is insignificant, they are very durable. But due to complex manufacturing technology and expensive materials, these models have a high cost.

One more type of product can be distinguished – prefabricated. These are the most unusual and expensive models. They consist of several parts: the front part and the rim to which it is attached. They also have beadlocks, which are used to secure the tire, and a tyrelock, which prevents the wheel from coming off. The bolts for such discs are made of titanium alloy - they must be durable.

The main advantage of prefabricated models is the ability to replace any part if necessary. And it doesn’t matter what material it is made of. Typically, wheels are made to order and used on expensive cars to emphasize the status and image of the owner.

Width and reach

The weight parameters of car wheels are the width of the rim and the wheel offset. The first indicator is calculated in inches. In the technical specifications, it is indicated by the letter J. That is, 5J means that the width is equal to five inches. It is indicated in the same place as the disk seat diameter.

But the indicator is important not only for the geometry of the car. The width of the products is also taken into account when choosing tires. Most of them are only suitable for certain types of drives, but slight errors are allowed.

The offset of a disk or wheel is the distance from the plane of its attachment to the hub to the central axis. The indicator can be negative, zero and positive. The first option is that the axis of symmetry goes further than the plane. With a zero parameter, they are located equally, and with a positive parameter, the axis is closer to the car.

The operation of the bearings in the hub and suspension depends on the offset. If it is incorrect, then the track may decrease or increase. Because of this, the chassis of the car wears out faster.

Before choosing wheels for a car, you need to consider the presence or absence of humps. These are protrusions on the surface that can be used to secure the tire without a tube. Almost all modern models have them. But if the car is old, and only retro wheels can be purchased for it, there may not be humps on them. Although they are fitted with tubeless tires, they are not sealed to the rims. When turning, the tire may simply fall off.

Choosing car wheels is a simple and even interesting process. You just need to carefully study the parameters of different models. Then you will be able to choose the right product.

How to choose the right wheels for your car

New alloy wheels on a car usually completely change its appearance and style. But how to choose the right wheels for your car? We'll tell you about the selection process, nuances and what you should pay attention to.

Nowadays you can find many cars that have non-factory wheels installed. Many will say that due to such a replacement, the appearance and style of the car also changes. Some car owners give it a sporty style, others an SUV style or simply highlight the car model.

It is very popular among young people to install alloy wheels on domestic cars. Foreign-made cars are also not ignored and are trying to give an exclusive style by making a lower landing, or vice versa, turning the crossover into an off-road monster.

It all depends on the taste and desire of the car owner, but desire alone is not enough, for this you need to know how to choose the right wheels and what you need to pay attention to. In the article we will tell you how abbreviations on disks are deciphered, what parameters are responsible for what, and what rules must be followed when choosing.

What categories are car rims divided into?

Car wheels are divided into two main categories - steel and alloy. Steel - often found as standard on old and new cars. Typically, steel is stamped from steel sheets and finally welded into one piece. The result is a cheap and high-quality product, which is why most cars on the factory assembly line are equipped with steel wheels.

The advantages of such steel rims are also considered to be high strength and easy recovery, even in the event of very severe damage. But it also has its drawbacks - inaccurate manufacturing, which entails frequent balancing, heavy weight and, of course, the design itself, which often does not please everyone.

Alloy wheels are superior to steel wheels in many ways. Thanks to light alloys, the design can be as varied as the color. The precision of manufacturing is tens of times greater than that of steel rims, and they also perfectly remove heat from the brake system. It can take a long time to talk about the pros and cons, since much depends on the alloy, shape and diameter of the light-alloy wheel.

In turn, alloy wheels are divided into two subtypes - forged and cast. As for the cast disk, it has a grainy metal structure inside, and this is the main disadvantage of this subtype. If you drive for a long time and often on bad roads or off-road, microcracks begin to appear inside, which then turn into large cracks. During a strong impact, it can crack and even burst.

Forged wheels are many times stronger than cast wheels. Instead of a porous structure inside, it has a multi-layer fibrous structure, which is what gives it its superiority. This subtype is not afraid of blows or chopped holes; some part of the suspension will sooner break than a forged one will bend or crack. Therefore, before choosing rims, you need to decide in what conditions the car will be used.

According to the rules and technology, wheels are cast and forged from magnesium and aluminum alloys. If we talk about the rating of alloy and forged wheels, then from worst to best it will be as follows:

• cast magnesium (despite being lightweight, it cracks very quickly);
• cast aluminum (optimal in terms of quality and price, withstands impacts well);
• forged aluminum (light and durable);
• forged magnesium (the most durable and lightest).

When choosing rims, you should understand that not everything that is cheap will be of high quality, and the technical parameters of the car also play a lot. Most often they choose aluminum ones, since magnesium ones are almost impossible to get; they are mainly made to order for sports cars. The price of magnesium wheels can start from $1000 apiece, so there is simply no point in installing them on a car that costs no more than $7000.

Therefore, it is better to choose more affordable options. The first thing you need to do is to understand the markings on the rims, since the deviation of one number can lead to a complete misalignment of the rims with the car. Each wheel rim has a marking, and it is considered international and standard. For example, let’s look at the markings 7.0×16 PCD5x115 ET40 D70.2:

1. 7 – disk width, measured in inches;
2. 16 – wheel rim diameter, measured in inches;
3. PCD5x115 – indicates that the disk has 5 holes for fastening, with a hole diameter of 115 mm;
4. ET40 - indicates the offset of the wheel rim, measured in millimeters;
5. D70.2 – diameter of the central hole of the disk is 70.2 mm.

For more details about these markings and what they are responsible for, see the article below. As you can see, you should select wheels not only based on manufacturing technology and beauty, but primarily based on the type and characteristics that match the car.

How to choose the parameters of car rims

To choose the right alloy wheels for your car, you need to understand what each marking is responsible for. In the store you may be asked to select rims based on the make of your car, but it’s a good idea to be sure of what you’re buying.

Disc offset - ET

Disc offset is often the distance from the plane that passes through the axis of the center of the rim width of the wheel itself, and to the plane that is adjacent to the hub. Typically the measurement range is up to 5 millimeters. In addition to the standard ET labeling, drivers often refer to it as a stem.

If the disc has a large overhang, it is necessary to try it on the hub, since after installation it may begin to rest against the fender liners or wheel arch. It can also rub against other suspension elements or the brake system. If the ratio of the reach to the vehicle's chassis is not observed, stability may deteriorate significantly, the steering may become sensitive, and the brakes will be distributed unevenly.

You should select wheels in such a way as to get what you want as much as possible, but at the same time comply with the parameters necessary for stable driving.

PCD – holes for mounting disks

Probably the most important role is played by the PCD parameter - the number of holes for mounting disks on the hub. This is where many buyers start their search, since not all cars allow you to change or even replace the fastening bolts. The manufacturer also indicates another number next to it, this is the diameter of the hole in millimeters, so that you can reliably know whether the bolts will fit in diameter or not.

It is advisable to choose 1 in 1 according to the diameter of the bolts. Deviations of 2-3 mm upward along the holes are allowed, but then there is the option of skewed wheel rims or a loose fit. The main thing is that the diameter of the PCD should not be smaller than the bolts on the car hub, in which case the wheel rim will not fit on the car at all.

What is HUMP

No less important parameter than PCD. In other words, this is the distance between the annular protrusions. They serve for additional fixation of the beads on tubeless tires during installation. As everyone knows, 99.9% of these wheels are fitted with tubeless tires, from the lowest to the highest for SUVs.

DIA – bore diameter at the center of the disk

After selecting the PCD, you need to select DIA, this is the central hole, or more precisely its diameter for fitting on the hub. There is a centering lug on the hub; its diameter must match the diameter (DIA) on the disk. Like the PCD diameter, the DIA diameter allows only upward changes.

Essentially, this is a list of those basic parameters that you need to know when you need to choose the right wheels before buying a car. Where should you start the selection procedure? The first is to take the parameters of your car’s hub. You need to decide how many bolts to secure the wheel rim, often it is 4.5 or 6 bolts, in rare cases 3 bolts. Larger pickups or SUVs may have more bolts.

Next, take a caliper and measure the diameter of the bolts, as well as the diameter of the centering protrusion on the hub. Don’t forget to write down the diameter of the wheel rim, so if you take a very large diameter, it will not fit into the wheel arches, it will simply constantly scratch on the fender liners. Over a short distance, such a disc will damage the chassis and suspension, and instead of the pleasant feeling of new wheels, you will end up with a lot of hassle and financial waste.

Experienced car enthusiasts, changing the size of the wheel rim up or down, and selecting the necessary tires, can lower the profile or, conversely, increase it. Thus, from an ordinary coupe, you can make a sporty, stylish car with excellent handling. A crossover can be turned into an SUV, which will gain high ground clearance and better cross-country ability.

Another main rule when choosing wheels is the appropriate rim width. There is a so-called golden rule - the width of the rim of the wheel should be 25% less than the width of the profile of the tire itself. The ideal option would be to match the wheel to the tire. Choosing a narrower wheel or a wider one will result in a violation of the tire profile. As a result, the car will be almost uncontrollable, and the tires will wear out very quickly, and the rims can easily be damaged. In rainy weather, this combination can lead to hydroplaning, or sliding on a flat road surface.

When replacing steel wheels with alloy wheels, it is also worth remembering that you may need to replace the bolts (or studs) with longer ones. Don't forget to look at how your wheel bolts are tightened - to a sphere or a cone. If you can’t figure out the selection of parameters, it’s better to go to a specialized store or ask experienced drivers in the garage. But you shouldn’t rush to buy the first rims you come across.

How to change wheels on a car

You can safely replace an already re-shod wheel on an alloy wheel at home. The replacement procedure will depend on how accurately the new rims fit in place of the old ones. If all the parameters match one to one, then it will be enough to remove the old wheels and install new ones in their place, following the usual wheel replacement procedure. If some parameters do not match, and most often this happens with the length of the studs or bolts, you will have to tinker a little with replacing them with new ones.

Having installed and screwed on the new wheel and tire, you need to shake it from side to side, thereby checking whether it fits tightly and whether there is any play.

The most important thing is that you shouldn’t even try to change alloy wheels at home.

The slightest wrong movement and a chip, dent or, much worse, a crack will appear on the new disk.

Therefore, you only need to change your shoes at a service station and preferably with an experienced specialist. The cost of rims varies greatly and can sometimes reach thousands of dollars per piece. Also, the price of alloy wheels will depend on the alloy and manufacturing method. We have already given a rating above; accordingly, the price will depend on the quality. Cast magnesium ones are considered the cheapest; on average, the price starts from $70 per one, but on the used spare parts market you can find cheaper ones in good condition. It is worth remembering that cast magnesium on top may be perfect, but have a lot of microcracks inside.

If we talk about cast aluminum, then their price is a step higher, and starts at $100. Depending on the manufacturer and form of manufacture, in some cases it can start from $300 per piece. The pricing policy for high-quality forged aluminum can start from $151 per piece. but sometimes for such a price they can slip in a high-quality fake, so you need to carefully read what is written on the package and not take the seller’s word for it.

The most expensive and most durable are forged magnesium, their price, as a rule, starts from $500 for the cheapest in this category, more or less normal ones will cost from $1000, or even more. Such wheels can be found on expensive sports cars of famous brands.

How to choose the right wheels is always the first question. Before you buy, decide in what conditions the car will be used and how much the car costs. So, if you buy a set of wheels for $2000, when the car itself costs $1500, you will worry more about the safety of the wheels than about the car itself.

How to choose wheels

How casting differs from forging, what offset is and why it is so important to take into account the recommendations of the car manufacturer - about all the intricacies of choosing rims in our review

Geometric parameters of the disk

When choosing wheels for “ordinary” use (we do not take into account various types of tuning), we strongly recommend that you stick to the parameters that are as close as possible to the factory ones. Why is this so important? Significant changes in parameters such as width, offset, diameter and weight of the disk can affect both the safety and ease of driving the vehicle, and the service life of the chassis components. So, for example, if we talk about the diameter of the disk, then its too large value (with the same outer diameter of the wheel) will adversely affect its weight.

When choosing rims, the proverb “measure seven times” is true.

More wheel weight means more unsprung masses, which, in turn, leads not only to an increased load on the suspension, but also to a deterioration in the smoothness of the vehicle. Also, due to greater inertia, a heavy wheel follows the road profile less readily, while a lighter wheel maintains tire contact with the surface longer, improving vehicle stability. In addition, an increase in wheel weight to some extent worsens equally important characteristics - the braking and acceleration dynamics of the car. Needless to say, larger diameter wheels shod with low-profile tires are easier to damage on Russian roads.

Larger diameter wheels shod with low-profile tires are easier to damage on Russian roads

An excessive increase in wheel width coupled with wider tires to a certain extent has its advantages (the car’s susceptibility to lateral loads improves), but there are, perhaps, more disadvantages: in addition to the increase in weight, this can have a worse effect on the vehicle’s stability when driving along longitudinal unevenness. On a rut, a car with wider wheels will obviously be less stable, and its handling will become more “nervous”. But even more “harmful” is playing with the wheel’s run-in, which can worsen the situation even more: the smaller the run-out (the wheel “sticks out” more), the more the optimal wheel running-in shoulder is disrupted (most often negative), the more sensitive it becomes to irregularities steering, and the load on the chassis elements is greater. Another danger of increasing the break-in shoulder is the lack of a stabilizing torque when braking with one of the faulty brake circuits. How far can you deviate from the standard parameters? There is no clear answer, because the chassis of each car is individual and reacts to such changes differently, but changes in offset by 2-3 mm most often remain without consequences.

We strongly recommend using standard size discs, and the smaller the disc diameter, the better. This statement is true at least for the majority of populated and not so populated areas of our country

When choosing, don’t be lazy and “try on” the rims to the tires - this can be done in numerous tire calculators. The rim should not be too wide or too narrow: for example, for a 205/55R16 tire, the rim width should range from 5.5 to 7.5 inches, but it is better to stick to the middle ground and go with a 6.5 x 16 rim.

Case material and price

The fact that alloy wheels are lighter than stamped ones should not mislead you. As a rule, a cast disk is either similar in weight or slightly lighter than a comparable steel one. However, most often when replacing disks, car owners try to increase the diameter of the wheel, and this entails an inevitable increase in weight, which, as we have already found out, does not lead to anything good. As a rule, an increase in rim diameter by 1 inch, coupled with an increase in tire width, makes the wheel assembly heavier by an average of 20–30%. But chasing low weight is also reckless. If a tire store salesperson offers you a “cast” that is too light, be wary: little-known companies, most often of Chinese origin, often actually produce extremely light wheels that do not stand up to criticism in terms of their strength.

Documents talking about the certification of Chinese wheels often turn out to be “fake” - not only will you be tortured to “roll” such wheels, but you’ll have to look for new ones to replace the ones that burst!

Forged wheels, of course, differ for the better in this sense: they are noticeably stronger and lighter, but due to the labor intensity of manufacturing, their price is noticeably higher, and the supply on the market is poorer: only 10% of the presented wheel manufacturing companies have in their assortment of forged wheels. “Forging” has another feature: when hitting an obstacle, the disc may retain its integrity, but the sidewall of the tire will take the entire impact, which in most cases is pointless to restore. Flying into holes, as you can see, is unprofitable in any case.

In addition to many Chinese ones, discs from some Russian manufacturers, and less often from European ones, also suffer from low strength. That is why when choosing, you should pay special attention to the status and integrity of the brand. If you don’t have such confidence, then it’s time to remember the golden words of Boris Razor from the movie “Big Snatch”: “Weight is reliability!”

Price is perhaps the determining factor when choosing wheels. And when it comes to tight finances, I recommend not chasing the beauty and size of rims - it is much wiser to choose standard and affordable stampings, and the money saved is better spent on high-quality tires - in this case, the performance characteristics of the car will remain at the same level, including the stability of the wheels to breakdown and ease of straightening disks when they are deformed. The design issue is resolved by installing additional caps (either factory or non-standard). It's another matter if the budget is not limited. In this case, the choice is simplified: it is best to consider the most proven brands. It would be better if it was a light forging, but even here we do not recommend chasing a low tire profile - safety is more expensive.

Estimated prices in online stores for the most popular wheel models suitable for Ford Focus 3 (PCD 5*108, Dia 63.3):

How to choose the right wheels for your car

Sometimes some novice car owners are faced with the need to replace one or more disks, and this task turns out to be more difficult than it looks from the outside. And no wonder: 4*108, 6J, ET47, Dia 63.3, R15 - what is all this?! Let's figure it out together.

Choose the right wheels for your existing car, simultaneously understanding all the necessary parameters.

Regardless of what kind of car you have, when choosing new wheels you need to consider the following parameters:

• disk type;
• mounting (or landing) diameter;
• number and diameter of mounting holes (PCD);
• disk width;
• disc ejection (ET);
• diameter of the central (hub) hole;
• shape of mounting holes;
• presence of humps.

Let’s make a reservation right away: if at this point you have lost the desire to deal with all these parameters, when choosing wheels, just use the car selection service in large online stores. There you can simply indicate the model of your car and get wheels that are guaranteed to suit it in all respects. Well, if the determination to find out everything is still with you, then let's get started.

Based on the type of manufacturing, all discs are generally divided into three types: stamped, cast and forged. The question of choosing a specific type is a topic for a separate article, but here we will present the main differences.

Stamped wheels are the cheapest: these are the same wheels that you see on the basic trim levels of budget cars, and they are usually covered with plastic decorative caps. They are made of steel and painted with enamel. Among their advantages, in addition to the lowest price, is high maintainability. The fact is that stamped discs do not break when hit, but become wrinkled, and can be easily repaired later. The main disadvantage of such wheels is their high weight and lack of design: this is a purely functional product.

Alloy wheels compete with stamped wheels in popularity. Such discs are made not of steel, but of a lighter alloy - usually aluminum. Thanks to manufacturing technology, cast wheels can have a wide variety of shapes, which, combined with a lighter weight than “stamps,” makes them popular. Among the disadvantages of such wheels, we can mention a higher price and lower maintainability: alloy wheels do not wrinkle when subjected to a strong impact, but crack. Of course, the technology of welding repair and rolling has long been mastered, but it is impossible to guarantee the preservation of the original properties after repair.

Forged wheels are the highest quality and most expensive option. They are manufactured using the hot die forging method, which provides the best internal metal structure and, accordingly, the highest strength at the lowest weight. The downside of this method is the low prevalence of products and the high price.

In addition to the above three types, there are also so-called prefabricated discs - but this is already exotic, and we will not touch on them. In general, for the average car owner the choice is between inexpensive, but boring stamped wheels and more expensive and beautiful alloy wheels.

This is a very obvious parameter: the diameter of the disc circumference in inches. As a rule, it is designated by the letter R: that is, the R 17 wheel has a diameter of 17 inches.

Let us especially note: the letter R itself does not refer to the diameter and comes from the tire parameters, where it is also mistakenly used to mean “radius”, in reality implying the seat diameter of the tire. In the case of a tire, R is a marking of the radial cord structure, but for a disk this marking is actually not relevant. However, the erroneous “radius” in the meaning of “diameter” and the accompanying R are so ingrained in speech that most sellers and disk selection services use it by default.

The permissible rim diameters for your vehicle are indicated in the owner's manuals and on stickers in doorways - along with the recommended tire pressure. When buying tires, it is worth remembering that their seat diameter must match the diameter of the rims.

It is not recommended to exceed the maximum diameter specified by the manufacturer: discs that are too large, in addition to potential geometric incompatibility, change the suspension operating parameters, affecting wear of the chassis. In addition, the larger the disc and the lower the rubber profile, the less comfort it promises to travel on bad roads. However, changes in diameter within the limits specified in the manual, and even an inch more, as a rule, occur without significant consequences.

This is the so-called “bolt pattern”: the number of holes and the diameter of the circle on which they are located (by the way, the English PCD is just the diameter of the circle, “Pitch Circle Diameter”). The number of mounting bolts can vary and increases with the weight and speed of the vehicle: usually there are 4-6, but it can be more or less (minimum 3). Most VAZ cars have a 4x98 bolt pattern, with the exception of Oka (3x98) and Niva (5x139.7), as well as new models like Largus (4x100).

The disc bolt pattern must be observed: despite the fact that some discs - for example, 4x98 and 4x100 - seem to be interchangeable, this is not the case. A seemingly insignificant 2 millimeter difference in the diameter of the circle on which the mounting holes lie will greatly affect the installation: only one of the four fastenings will be correctly tightened, and the rest will be offset from the center, causing the wheel to run out. The problem can be partly solved by using bolts with a “floating cone” (more on them below), but in general, the use of disks with inappropriate bolt pattern parameters should be avoided.

This parameter is as simple as diameter: it is the width of the rim in inches. Usually in the list of parameters it is designated by the letter J: for example, 5.5 J is a disk five and a half inches wide.

The width of the disk is usually indicated in the same places as the permissible mounting diameter, along with it. In addition to the geometric parameters for the car, the width of the rim is also important when choosing tires: the tire is designed for use with a rim of a certain width, but with a certain permissible error.

Disk offset is the distance from the mating plane of the disk to the hub to the longitudinal axis of symmetry of the disk. Let's put it simply: the central axis of symmetry is a line dividing the disk in half along the width described above, and the mating plane is the point where the disk comes into contact with the hub and is screwed to it.

The offset can be positive, zero and negative: if the axis of symmetry lies closer to the car than the mating plane, then the offset is positive, if they are on the same axis, then the offset is zero, and if the axis of symmetry is more distant from the car than the mating plane, then it is positive . In other words, the greater the offset, the deeper the disc sits in the wheel arch, and the smaller it is, the more the disc protrudes outward.

Reach is a fairly important parameter: it also directly affects the performance of the suspension and wheel bearings. Incorrect offset not only increases or decreases the track, but can also cause accelerated wear of the undercarriage and bearings.

The diameter of the central hole is a parameter that does not need additional explanation. In the list of disc characteristics, it is usually designated as "Dia", "DIA" or "D". This is also an extremely important indicator: if the central hole of the disk is smaller than required, the disk simply cannot be installed, and if it is larger, then centering rings will be required to center the disk on the hub.

Many people mistakenly believe that when installed, a disc with a center hole that is too large will center itself on the hub by tightening the bolts, but this is not the case. Accordingly, runout and vibration that do not disappear after balancing the wheels is a reason to check the coincidence of the diameters of the central hole of the disk and the hub and the presence, if necessary, of centering rings.

The shape of the mounting holes is important in terms of the type of bolts or nuts that will secure the drive. As a rule, bolts and nuts for stamped discs have only a slightly conical shape of the plane adjacent to the disc when tightened, and the bolts are also noticeably shorter in length.

The latter is due to the minimum thickness of the stamped disk. A cast disk is noticeably thicker than a stamped one, and in addition, its mounting hole has a more pronounced conical shape, which requires the use of different fasteners. In addition to the conical seat, the mounting hole of some disks can be designed for the use of fasteners with a hemispherical and flat working part.

And one more thing: there are bolts with a so-called “floating cone”: they allow you to partially compensate for a slight discrepancy between the PCD disk and the required parameters. The working conical part of such bolts is made in the form of a separate ring placed on the bolt and moves relative to the longitudinal axis of the bolt when tightened.

Humps are protrusions on the outer surface of the rim that secure the tubeless tire to the rim. Remember the popping noise that is heard when a tire shop inflates a tire after installing it on a rim? This is the moment of “landing” of the tire: the bead ring of the tire sits between the hump and the edge of the rim. In fact, this indicator is listed last in our material, because at present it is practically not relevant: almost all modern wheels are designed to accommodate tubeless tires and have humps.

However, if, for example, you decide to purchase retro wheels of considerable age, keep in mind that they may well be designed to install exclusively tube tires without having humps. However, you can install tubeless tires on them, but the question of its tight fit, as well as safety when driving, will remain open: if there is insufficient pressure in the tire, the risk of “taking off your shoes” in a turn will be very high.