Disks in the car - how to decipher the markings and choose the right disks?

The desire to have more of everything in cars is now on an unprecedented scale. There should be more power, more comfort, more sensations, and the car itself should attract more attention. Rims are a unique element of a car because we don't see them while driving. However, drivers are more likely to buy cars with good rims and can pay big money for them. Everything to be beautiful. Is it only the aesthetic aspect that matters?

Wheels for cars - what you need to know about them?

Hoops can be divided according to different criteria: 

• material type;
• originality;
• ET parameter;
• number and distance between fixing screws. 

In this guide, we will not focus on aesthetic values ​​(after all, this is an individual matter), but on the technical aspects of choosing a rim for a car. Pretty rims or ugly rims are just a matter of taste, so it's worth focusing on other issues. Even the most expensive and beautiful wheels will be useless if you do not pick them up under the hub, wheel arch and suspension.

How to choose wheels for a car?

The first parameter is the size, which is critical. It is in inches and indicates the diameter of the rim without the tire. The most popular sizes in passenger cars are in the 14-17 inch range. In addition, a necessary parameter to be aware of is the bolt spacing and number (PCD). If you don't know this, you won't be able to fit the rim onto the hubs correctly.

You must also consider the ET designation, i.e. rim offset. Expressed in millimeters. Another absolutely key point is the diameter of the centering hole (CA).

What wheels to choose for the car?

Choose rims that will technically and aesthetically match your vehicle. Too large wheels with a small tire profile will dampen bumps worse, which will affect driving comfort. Wide rims will give you very good driving performance, especially in corners, but at the expense of increased fuel consumption.

Disks - what to choose?

However, if you exaggerate the other way, very narrow and small wheels will make the car almost caricature.

Some drivers opt for two sets of discs. This allows them to independently change the wheels in autumn and spring. However, so that you can get detailed answers to the above question and dispel your doubts, we will try to clearly and accurately explain all the secrets related to rims.

Selection of disks for a car, i.e. size details

What marking do you most often see on the disks in the car? This is an embossed string of letters and numbers that might look like this: 7,5Jx15H2 ET40. What should you do when you see such a line?

Rim width and flange profile

Let's start from the very beginning, that is, with the marking 7,5J. The numerical value in this particular case is the width of the rim (measured in inches). In this case, 7,5 inches translates to 19,05 cm. The "J" refers to the profile of the rim flange and means that it is suitable for passenger cars.

Selection of rims to the car and rim contour

The next element seen in the character and number example is 15. The number here simply means the size of the rim in inches, which in this case is the popular "fifteen". It is on the basis of this parameter that rims are most often chosen.

Often, a completely underestimated marking is after the number indicating the size of the rims, i.e. H2. This is how the manufacturer determines the number of "humps" used in the cross-sectional profile of the rim. The type and number of lugs affects the stiffness of the entire rim. In the present case, this means a double hump.

ET discs - what is it?

What is ET, i.e. landing on the rim, actually - her excommunication? This parameter defines the distance between the rim mounting surface and the center line of the rim. Although this definition sounds very mathematical at first glance, it is not difficult to understand.

In practice, it is about how deep the rim will go into the wheel arch. The higher the ET, the deeper the wheel will hide in the wheel arch. If you reinstall the rim, you may have difficulty installing the wheel, which will rub against the suspension components.

ET drives - what does it affect?

On the one hand, you should not bet on too much rim overhang. On the other hand, a very low ET (or even negative) will not be good either. In this case, the wheel is strongly pushed outward and in extreme cases the tire may rub against the wheel arch. You will have problems while driving, and in the event of a heavy load and falling into a hole, you can even destroy the tire.

Correspondence of disks to the car in terms of PCD and OC

Another parameter that we did not include in the sample string of characters and numbers is PCD. This means the number and distance between the rim bolts. For 15" discs, PCD 5x112 is usually used. This refers to 5 pieces of mounting screws (or holes) that are installed on a circle with a diameter of 112 mm.

How to adjust the center hole?

The designation OS is responsible for the diameter of the centering hole in the rim. It should match the outer hole of the hub where the rim sits. In original products, this parameter is ideally matched to the hub. When replacing, it will be necessary to retrofit with centering rings.

The smart choice of rims for your car

You already know some of the basic sizes and markings on the rims, so you can look for the right ones. However, this does not mean that you can completely let your imagination run wild and put any wheels on your car. What happens when you overdo it with a parameter?

Choose ET Wisely

Too wide rims combined with a very positive ET is a bad combination. In this case, the tires will touch the internal suspension components. Sometimes he just won't be able to install such wheels because they won't fit into the wheel arch.

Exaggeration in the other direction, i.e. a negative ET value, will not only cause the tire to rub against the wheel arch. During a roadside check, a police officer may find that the tire is protruding from the contour of the car and will give you a ticket.

Cheap car rims - are they worth it?

New disc sets can cost up to several thousand PLN. It is clear that not everyone can afford such expenses, especially when the wheels cost half the cost of the car. In such situations, there are two options - wheels for cars from China or the secondary market. What to choose?

New Chinese wheels or used? What wheels to choose for the car?

The decision is not easy, because on the one hand, attractive prices, and on the other hand, concern for quality. However, not all products of Chinese origin should be discarded immediately. All you have to do is choose a trusted brand. What if you choose the second option? The key to buying used components is to check their quality, such as whether they are straight and whether they have been welded.

What are sports rims for a car?

They are usually made from large aluminum or carbon rims. The large rim diameter contributes to better brake cooling, while the material used to reduce weight is critical to vehicle performance. Discs of this type are usually wide and have a unique design, unlike, for example, factory options.

Are sports rims suitable for everyday driving?

However, what is suitable for sports may not work in everyday use. Therefore, sports discs are most often used for motorsport. On very large discs, unsprung weight increases. Vibrations transmitted to the body make the trip much less comfortable.

Large rims also force you to opt for low profile tires. Such a connection adversely affects the operation of the suspension. More vibrations and vibrations cause this element to wear out faster.

If you are looking for a rim, the manufacturer's suggested rims are the best.. You can also use online calculators and choose the right set for yourself. In addition to the wheels themselves, do not forget about good quality tires. You already know how to choose wheels and know their parameters, so in the end we can only wish you a wide road!