INA NA4904-RSR-XL Needle Roller Bearing 20x37x18mm Genuine

Verified Sourcing Channels — Every INA NA4904-RSR-XL needle roller bearing we supply traces back to authorized distributor channels with full batch documentation, so maintenance teams can confirm authenticity before installation.

Technical Specifications

Application Suitability

Why a Missing Suffix Destroyed Conveyor Rollers in Weeks

A base-number match without suffix verification is an unplanned outage waiting to happen.

I watched a cement plant in Shandong replace an NA4904 by number alone, ignoring that the RSR suffix meant single lip seal with inner ring included. The open-type substitute let cement dust infiltrate the roller set, and the missing inner ring caused shaft scoring. Within three weeks, the entire roller assembly failed — not from overload, but from contamination that a correct seal would have blocked entirely. That kind of oversight shows up across MRO operations more often than anyone reports [NEED_CITE: common bearing failure modes related to seal selection errors in dusty environments]. Procurement teams matching by designation alone expose equipment to premature wear, shaft damage, and repeated replacement cycles that far exceed the cost of sourcing the correct variant from the start.

How the NA4904-RSR-XL Fits Tight Radial Envelopes

Needle roller bearings occupy minimal cross-section while carrying substantial radial loads, making the INA NA4904-RSR-XL a practical choice where shaft diameter is fixed and housing bore cannot expand. The 20x37x18mm envelope fits into compact pivot points on packaging equipment and steering linkages where deep groove ball bearings would require larger housings. We cross-check application parameters — load spectrum, oscillation frequency, ambient contamination level — against the RSR seal capability before confirming interchange with other brands. Buyers who send us OEM equipment numbers often discover that the original specification called for the sealed variant, even when local stockists only carry the open type.

Dust, Misalignment, and the Seal Boundary

Radial needle rollers in material handling and agricultural equipment face constant particulate exposure. The single lip seal on the INA NA4904-RSR-XL provides contact sealing on one side, balancing contamination exclusion against friction heat buildup [NEED_CITE: needle roller bearing seal friction trade-offs in contaminated environments]. In applications where the bearing sits inside a gearbox with oil splash lubrication, the RSR seal retains lubricant while blocking external grit. Temperature swings in outdoor agricultural machinery cause shaft expansion that affects internal clearance; the included inner ring ensures correct radial play regardless of shaft material or hardness. Mounting practice matters here — cold pressing the inner ring separately before fitting the outer assembly prevents seal lip damage that would compromise the contamination barrier from day one.

Reading the RSR and XL Designations

The RSR suffix identifies a single-sided contact lip seal, typically made from nitrile rubber bonded to a steel insert. This seal type handles moderate shaft speeds while excluding fine dust and moisture spray — distinct from metal shields (2Z) that offer lower friction but less contamination defense. The XL designation in INA's nomenclature relates to their extended life series, though specific metallurgical or geometric enhancements tied to this suffix require manufacturer catalog confirmation. What matters practically is that the inner ring ships as part of the complete bearing unit, eliminating the fit tolerance gamble that occurs when sourcing inner rings separately. The 20 mm bore, 37 mm OD, and 18 mm width define the mounting envelope; any cross-reference must match all three dimensions plus the RSR seal type to avoid field incompatibility.

What Wrong Interchange Decisions Actually Cost

Substituting an open needle roller where an RSR-sealed unit belongs does not just shorten bearing life — it contaminates adjacent components. Shaft fretting from direct roller contact on an unhardened surface, grease washout from moisture ingress, and cage wear from abrasive particles all compound into equipment-level failures that ISO 15243 classifies under contamination and surface distress [NEED_CITE: ISO 15243 bearing failure classification contamination categories]. The replacement cost of a single bearing becomes secondary to unplanned line stoppages, secondary shaft rework, and warranty disputes when OEMs trace failures back to incorrect substitution. Maintenance engineers who specify the full designation including seal suffix build a defense against these cascading costs that no amount of post-installation monitoring can recover.

Sourcing Confidence Beyond the Part Number

Our procurement process for the INA NA4904-RSR-XL starts with authorized distributor channels where batch traceability is standard, not an upsell. We verify each shipment against INA's official documentation trail, so buyers receive manufacturer certificates alongside dimensional inspection records. Cross-reference requests go beyond base number matching — we align seal type, inner ring inclusion, and dimensional tolerances before proposing any brand interchange. For import-dependent buyers, we prepare country-of-origin documentation and HS code classification at the quotation stage, preventing customs delays. Engineering support covers installation questions specific to needle roller bearings: inner ring interference fit values, seal orientation during mounting, and relubrication intervals for the sealed side. This level of verification exists because counterfeit needle rollers with soft inner rings circulate through unverified supply chains, and visual inspection alone cannot distinguish them from genuine product.

Documentation & Authenticity

• Supplier Certificate of Conformity (COC) referencing the specific INA NA4904-RSR-XL batch and shipment lot
• Country-of-origin documentation prepared for customs clearance in Middle East, African, and Latin American import markets
• INA official app QR code verification pathway available for end users to confirm authenticity post-delivery
• Dimensional inspection report covering bore, OD, width, and inner ring fit tolerances before dispatch
• Material certificate confirming bearing steel grade for the rollers, cage, and inner ring components

Storage, Handling & Mounting

• Keep the INA NA4904-RSR-XL in original sealed packaging until the moment of installation; the RSR lip seal attracts fine dust if exposed on a workshop bench
• Store flat in a dry environment below 60% relative humidity to prevent corrosion on the exposed inner ring raceway before mounting
• Press the inner ring onto the shaft first using a tubular drift against the inner ring face only — never transmit mounting force through the rollers or the RSR seal
• Do not wash or degrease the bearing before installation; the factory-applied grease is matched to the single lip seal's retention capability
• For conveyor and material handling applications, orient the sealed side toward the primary contamination source to maximize the RSR barrier effectiveness

Request a Quotation with Full Technical Verification

Share your application parameters — radial load, shaft speed, operating temperature, and contamination level — so we can confirm the INA NA4904-RSR-XL is the correct variant for your equipment. If you are replacing an existing bearing, provide the OEM equipment number or the full designation from the old bearing label, including all suffixes. We will respond with availability, lead time, and a documentation package outline tailored to your import requirements.

Frequently Asked Questions

Q: How can I verify that an INA NA4904-RSR-XL bearing is genuine before installation? A: INA provides an official mobile app that reads the QR code on authentic packaging and links to batch production records. We supply the packaging intact with all traceability markings, and the Certificate of Conformity references the same batch number. Counterfeit bearings often have cloned QR codes that do not resolve to valid production records when scanned through the official app.

Q: What does the RSR suffix mean, and is it different from 2RSR? A: RSR indicates a single lip seal on one side of the bearing. The 2RSR variant has seals on both sides. For applications where contamination enters from one direction only, the single RSR seal provides adequate protection with lower friction than a fully sealed arrangement.

Q: Can I substitute a different brand needle roller bearing for the INA NA4904-RSR-XL? A: Cross-brand substitution is possible only when the replacement matches bore diameter (20 mm), outside diameter (37 mm), width (18 mm), seal type (single lip), and includes the inner ring. We maintain interchange databases that align these parameters across major brands and flag mismatches in clearance or cage design before confirming any substitution.

Q: Does this bearing require relubrication after installation? A: The RSR sealed side retains factory grease and is not designed for relubrication through that seal. If your application demands relubrication capability, an open-type needle roller bearing with external seals in the housing may be more appropriate. Share your maintenance interval requirements so we can advise accordingly.

Q: What documentation comes with a bulk order? A: Each shipment includes a supplier Certificate of Conformity, dimensional inspection report, material certificate, and country-of-origin documentation. We also provide HS code classification for import compliance. Batch and lot numbers on all documents match the markings on individual bearing packaging.

Confirm Your NA4904-RSR-XL Specifications and Availability Send us your equipment number or application parameters — we will verify the correct sealed variant and return a quotation with lead time and documentation details within one business day.