WHEELS 18 Summer MERCEDES SLK R172 SLK R171 SLK AMG R171 Kumho 225/40 R18

The model:determines the appearance of the rim. By entering the model in the LadneFelgi.pl store search engine, you can search for rims in different colors and with other parameters.

Rim size: refers to the diameter of the rim given in inches (1 inch = 2.54 cm). The possible sizes are predetermined by the vehicle manufacturer. Using rims smaller than those specified by the manufacturer is not allowed.

Rim width: is measured between the rim flanges. The dimension is in inches. When choosing tires, take into account the width of the rim and the car manufacturer's recommendations.

ET, offset: is not a strictly defined parameter, such as spacing. It depends on the width of the rim. ET is given in mm. The smaller the offset, the more the rim is, which increases the wheelbase, positively influencing the car's stability. The service book or ASO provides only the parameters of the currently installed rims.

Center bore: it is the dimension of the rim center hole diameter given in mm. If the car has a smaller hub diameter, centering rings are used. The ring is used to center the rim in relation to the car's hub. After screwing it, no force acts on it. It is a safe solution used by all rim manufacturers.

Color: determines the colors in which the offered item was made. Pictures are taken under natural lighting.

Certificates: confirm the compliance of the wheels with applicable quality and safety standards based on durability and quality tests. Some certificates, such as TÜV, additionally confirm that the wheels meet specific technical requirements related to compatibility with a particular vehicle model.

4 identical: the set consists of 4 identical rims, suitable for installation on all wheels of the vehicle.

Mixed: the set includes 2 rims intended for the front axle and 2 for the rear, taking into account possible differences in ET parameters or rim width.

TPMS Sensors - the parameter determines whether the TPMS pressure sensors can be used with a given rim.

Product presentation on YouTube: copy the link and paste it into your browser's address bar to watch the 360° wheel video.

Tire size: this is the tire size designation, for example 225/45 R18:

225 – tire width in millimeters,
45 – aspect ratio, meaning the sidewall height is 45% of the tire width,
R – indicates radial tire construction,
18 – inner diameter of the tire (rim size), expressed in inches.

Tire width: the measurement defining the distance between the tire’s side edges (measured in millimeters). Wider tires provide a larger contact area with the road, which can improve grip but may also increase rolling resistance and fuel consumption. Narrower tires generally perform better in wet and winter conditions but offer a smaller contact area with the road.

Tire profile: is the percentage ratio of the sidewall height to the tire's width. A lower profile means a smaller sidewall height relative to the width – such tires usually offer better handling precision, but at the cost of comfort and increased susceptibility to damage. A higher profile provides better shock absorption and greater ride comfort, although it may slightly reduce cornering stability.

Tire diameter: the value given in inches that specifies the size of the rim for which the tire is intended. It affects the tire’s fit to the wheel and indirectly influences handling and ride comfort.

Tire manufacturer: a company responsible for designing and producing tires. Each manufacturer uses its own technologies and rubber compounds, which affect the quality, performance, and durability of the offered tires.

Tread pattern refers to the specific design of the arrangement of blocks, grooves, and sipes on the tire surface. Its construction affects grip, water evacuation, and noise levels, as well as the tire’s adaptation to different driving conditions (e.g., dry, wet, or winter surfaces).

The speed index is a letter designation that indicates the maximum speed at which a tire can safely operate while maintaining the allowable load. According to the law, a tire should have at least the speed index (and load index) recommended by the vehicle manufacturer. It is possible to use tires with a higher speed index, which is often permitted by the vehicle manufacturer.

The load index (also known as the load rating) is a numerical indicator that specifies the maximum permissible load a single tire can carry at the recommended pressure and within its speed rating. Each numerical load index corresponds to a specific weight (given in kilograms), e.g., 91 means 615 kg.

Tire season: indicates the weather conditions for which the rubber compound and tread pattern are designed. Summer, winter, or all-season. A compromise between summer and winter tires; they perform well in various climatic conditions, but in extremely hot or winter climates they are significantly inferior to dedicated tires.

In Poland, the PN-C94300 standard "Tyres – packaging, storage and transport" is in force. According to its guidelines, tires can be placed on the market, stored, distributed, and sold without restrictions for up to 3 years from their production date. The tires retain all their safety and performance properties.