Guide to Decoding NSK and RHP Bearing Codes

Imagine urgently needing to replace a bearing, only to be confronted by an incomprehensible string of letters and numbers. Different manufacturers, different standards—it's enough to make anyone's head spin. This guide will demystify the numbering systems used by NSK and RHP bearings, helping you understand the secrets behind these critical components.

Founded in 1916, NSK (Nippon Seiko Kabushiki-gaisha) has spent over a century innovating in rolling bearing technology. With a global network of research, production, and technical centers, NSK maintains leadership through continuous improvement in product design, material science, and lubrication technology. Today, it stands among the world's premier manufacturers of rolling bearings, linear motion components, and steering systems.

NSK operates on a core philosophy: enhancing vehicle and equipment reliability through superior products and services. Its engineering teams collaborate closely with clients to develop optimized solutions, ensuring competitive advantage in demanding markets.

A bearing's alphanumeric code functions as its unique identifier, specifying type, dimensions, and construction. Complete bearing designations typically comprise three elements:

• Basic designation: Indicates bearing type and bore diameter
• Prefix: Denotes special designs or components
• Suffix: Specifies modifications or special features

While basic designations follow DIN 623 and ISO standards, prefixes and suffixes vary significantly between manufacturers—a crucial distinction for proper bearing selection.

The 3-5 digit basic code reveals essential bearing characteristics:

Positioned before the basic designation, prefixes indicate special designs:

• A: Optimized internal design
• K: Tapered bore
• W: Relubrication features

Following the basic designation, suffixes specify performance characteristics:

• B: Enhanced precision
• C: Reduced internal clearance
• ZZ: Dual shields
• M: Machined brass cage

After NSK acquired RHP (UK's former bearing leader) in the 1990s, both brands maintained distinct coding systems. Key RHP-specific suffixes include:

• 2RS: Dual rubber seals (equivalent to NSK's ZZ)
• TVH: Phenolic resin cage
• TN9: Molded nylon cage

• 6205ZZ (NSK): Deep groove ball bearing (6), medium series (2), 25mm bore (05×5), dual shields
• 6004-2RS (RHP): Deep groove ball bearing (6), extra light series (0), 20mm bore (04×5), dual rubber seals

Understanding these coding systems transforms bearing identification from frustrating puzzle to straightforward process. Whether specifying new components or replacing existing ones, this knowledge ensures optimal bearing selection for performance and longevity.