SNR: How to Read Bearing Codes and Designations

SNR bearings, like most modern bearings, follow a standardized designation system that allows identifying their main characteristics just by reading the code printed on the ring. Understanding this nomenclature is key to selecting the correct bearing, avoiding purchase errors, and simplifying maintenance.

In this guide, we explain how to interpret SNR codes, from the basic structure to the most common prefixes and suffixes. With this information, you will be able to communicate precisely when requesting a quote or replacing a bearing.

The code of an SNR bearing consists of a series of numbers and letters that indicate the type, dimensional series, bore diameter, and, in many cases, special characteristics. The central numeric part usually follows the ISO standard, so it is similar to that of other brands.

For example, in a deep groove ball bearing, the basic numeric code such as 6205 indicates a specific series: the first digit (6) corresponds to the bearing type, the second (2) to the width series, and the last two (05) multiplied by 5 give the bore diameter in millimeters (25 mm). SNR uses this same logic in its designation.

It is important to remember that this numeric structure is common to many manufacturers, but prefixes and suffixes may vary. SNR has its own letters to indicate internal characteristics, materials, or seals.

Prefixes in SNR codes appear before the basic number and usually indicate the bearing type or a construction variant. For example, the letter E may indicate a reinforced or higher capacity series, while other letters may refer to thin-section or stainless steel bearings.

In some cases, SNR uses prefixes to identify high-precision angular contact ball bearings or bearings for specific applications. It is essential to consult the SNR technical catalog to confirm the exact meaning of each prefix, as it may vary by series.

When requesting a quote for an SNR bearing, it is always advisable to provide the complete code, including prefixes and suffixes, to ensure the correct part is received.

Suffixes are letters or combinations of letters added after the basic number and provide information about specific characteristics. The most common in SNR are those indicating the type of seal or protection: 2RS for rubber seals on both sides, Z for a metal shield, and ZZ for two shields.

Another frequent suffix is C3, which indicates an internal clearance greater than normal, useful in applications with high temperatures or forced fits. There are also suffixes for special cages, such as EJ for steel sheet cage, or for bearings with special heat treatment.

In tapered roller bearings, SNR may use suffixes such as B to indicate modified contact angle or J for pressed steel cage. The combination of suffixes allows adapting the bearing to particular working conditions.

To illustrate the nomenclature, let's look at some typical examples. An SNR 6205 2RS C3 deep groove ball bearing would be a bearing of the 62 series, with a 25 mm bore, rubber seals on both sides, and C3 internal clearance. If the code were SNR 6205 ZZ, it would have metal shields instead of seals.

In the case of a tapered roller bearing, a code like SNR 30205 J2 would indicate a metric series with a steel cage and certain internal characteristics. The letter J usually refers to the cage, and the number 2 may indicate a specific variant.

These examples show how the combination of numbers and letters completely defines the bearing. When requesting a quote, it is advisable to send a photo of the bearing or the complete code printed on the ring to avoid confusion.

To identify an SNR bearing, first read the complete code engraved on one of the rings. If the bearing is very worn or the code is illegible, key measurements can be taken: inner diameter, outer diameter, and width. With these dimensions and the bearing type, the approximate code can be deduced.

It is also useful to observe the type of seal, cage, and any additional markings. SNR usually engraves its logo and code clearly. In case of doubt, the technical team at MR Accesorios Industriales can help you identify the correct bearing from a photo and measurements.

Remember that an error in the designation can lead to installing an inadequate bearing, with consequences for equipment life and performance. Therefore, it is always advisable to verify the code before purchasing.

Many users have doubts about interpreting SNR codes. For example, whether a suffix is exclusive to SNR or interchangeable with other brands. In general, the ISO standard ensures that the basic numeric part is equivalent, but suffixes may vary between manufacturers.

Another common question is about the difference between 2RS and ZZ. While 2RS offers greater protection against contaminants and retains grease better, ZZ is more suitable for high speeds and moderate temperatures. The choice depends on the application.

If you have specific questions about an SNR code, do not hesitate to contact us. At MR Accesorios Industriales, as an official SNR distributor, we provide technical advice and quote the bearing you need.