Description
Authorized Channel Sourcing — Every INA NA4908-RSR needle roller bearing we ship traces back to Schaeffler authorized distributor inventory with batch-level documentation.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | INA NA4908-RSR |
| Bearing Type | Needle Roller Bearing with Inner Ring |
| Bore Diameter (d) | 40 mm |
| Outside Diameter (D) | 62 mm |
| Width (B) | 23 mm |
| Seal or Shield Type | Single Lip Seal (RSR) |
| Number of Rows | Single |
| Cage Material | With Cage |
| Material | Bearing Steel |
| Weight | 0.024 kg |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Industrial Machinery | Conveyor cam followers, packaging machine pivot shafts |
| Electric Motors | Auxiliary drive shaft supports, fan bearing journals |
| Automotive and Heavy Vehicle Repair | Steering column joints, transmission rocker arms |
| Agricultural Machinery | Harrow adjustment linkages, sprayer boom pivots |
| Material Handling | Forklift tilt cylinder trunnions, hoist sheave pins |
Why a Missing Seal Suffix Wrecks Needle Roller Life on Dusty Lines
The RSR single lip seal is not optional trim — it is the only barrier between precision-ground needles and abrasive contamination.
Needle rollers operate with high line contact stress across a compact envelope. When an open-type substitute is installed in place of a sealed NA4908-RSR, particulate ingress begins almost immediately. Cotton lint, grain dust, or cement fines pack into the cage pockets, creating skid marks on the inner ring raceway within the first maintenance cycle [NEED_CITE: needle roller bearing contamination failure modes per ISO 15243]. Procurement teams matching only the base designation — ignoring the RSR suffix — are responsible for a significant share of these premature seizures. The cost rarely shows up on the purchase order; it surfaces as unplanned line stops and shaft scoring that demands complete assembly replacement.
How the NA4908-RSR Fits Compact Radial Envelopes
The 40×62×23 mm cross-section of the INA NA4908-RSR needle roller bearing with inner ring delivers high radial load capacity in applications where housing bore space is constrained. This geometry suits cam follower pivots, rocker arms, and guide rollers that cannot accommodate larger deep groove or spherical roller alternatives. We routinely cross-check envelope dimensions against OEM equipment numbers to confirm fit before quoting, eliminating the trial-and-error returns that plague catalog-only ordering.
Radial Load, Low Speed, and Contaminated Air: The Operating Reality
Needle roller bearings in this size range typically carry moderate to heavy radial loads at low to moderate rotational speeds. The dominant failure risk is not fatigue spalling but surface wear from contamination and inadequate sealing. The single lip seal on the NA4908-RSR provides contact-type exclusion of airborne particulates while maintaining low friction torque, a necessary balance for continuous-duty pivots that cannot be accessed for frequent relubrication [NEED_CITE: seal friction versus contamination exclusion trade-off in needle roller bearings]. Operating temperatures remain within standard bearing steel limits under these conditions, so thermal expansion effects on internal clearance are secondary to seal integrity as a life-determining factor.
Reading the Spec Sheet: Cage, Seal, and Inner Ring Details
The INA NA4908-RSR ships with a pressed steel cage that maintains uniform needle spacing, preventing roller-to-roller contact that would generate localized heat and surface damage under radial load. The single lip seal (RSR) contacts the inner ring outer surface on one side, leaving the opposite end open — an intentional design choice for applications where one face is shielded by the housing or adjacent component. The integrated inner ring provides a hardened, ground raceway for the needle rollers, eliminating the need to harden and finish the shaft journal to the same specification. This matters in repair scenarios where the original shaft surface is scored or pitted: the inner ring slips over the prepared journal and presents a fresh raceway to the rolling elements.
The Hidden Expense of Dropping the Suffix
Substituting an open needle bearing for the sealed NA4908-RSR may save marginally on unit cost but introduces contamination-driven failure that voids warranty and triggers unplanned downtime. ISO 281 life calculations assume clean lubrication; once abrasive particles breach the cage, actual service life collapses well below the calculated L10 value [NEED_CITE: ISO 281 bearing life reduction under contaminated lubrication conditions]. Counterfeit units compound the problem — soft inner rings and cloned markings pass visual inspection but spall within weeks under load. Sourcing a genuine INA NA4908-RSR needle roller bearing with verified traceability eliminates both risks in a single procurement decision.
What Changes When You Source Through Our Channel
Our authorized distributor pipeline delivers INA NA4908-RSR units with batch-linked Certificates of Conformity, not generic packing slips. Each shipment includes QR code verification paths compatible with Schaeffler’s official authentication tools, so receiving inspectors can confirm provenance before the bearing leaves the storeroom. When a buyer needs a cross-brand interchange — matching seal type, cage configuration, and dimensional envelope across SKF, NSK, FAG, TIMKEN, NTN, or KOYO catalogs — we align all three parameters rather than swapping on bore and OD alone. Country-of-origin documentation accompanies every export order, smoothing customs clearance for buyers in regions where import compliance scrutiny is tightening.
Documentation & Authenticity
- Supplier Certificate of Conformity listing batch and lot numbers tied to the INA NA4908-RSR shipment, enabling downstream traceability for regulated maintenance programs
- Third-party dimensional inspection report confirming bore diameter, outside diameter, and width against published INA tolerances before dispatch
- QR code verification pathway through Schaeffler’s official product authentication application for on-site counterfeit screening
- Country-of-origin certificate prepared for each export consignment, supporting customs documentation and preferential tariff claims where applicable
- Material test certificate confirming bearing steel grade for the inner ring and outer shell, available with the shipment documentation package
Storage, Handling & Mounting
- Retain the factory-sealed packaging on each NA4908-RSR until the moment of installation; premature opening exposes the single lip seal lip to workshop dust that compromises its exclusion capability before the bearing even enters service
- Store sealed units horizontally in a climate-controlled storeroom below 60% relative humidity to prevent condensation corrosion on the exposed inner ring bore surface
- Handle the bearing with clean lint-free gloves to avoid transferring skin oils onto the ground inner ring raceway, which can initiate corrosion pits under the needle roller contact zone
- Mount the inner ring onto the shaft journal using an induction heater set within the manufacturer’s recommended temperature range; cold-press fitting risks cocking the ring and deforming the single lip seal on the adjacent face
- Verify shaft shoulder squareness before pressing the NA4908-RSR into position — misalignment transfers directly into the needle rollers as uneven load distribution, accelerating cage wear on the high-stress side
Starting Your NA4908-RSR Inquiry
Send us your operating parameters — radial load, speed, ambient temperature, and contamination level — so we can confirm the sealed configuration matches your environment. If you are replacing an existing bearing, share the OEM equipment number or the marking on the removed unit; we will run a cross-reference check covering seal type, cage design, and dimensional envelope. Request the documentation package and country-of-origin confirmation with your quotation so import paperwork is ready before the shipment departs.
Frequently Asked Questions
Q: How can I verify that an INA NA4908-RSR needle roller bearing is genuine and not a counterfeit?
A: Check the laser-etched marking on the outer ring for font consistency and depth, scan the QR code on the packaging using Schaeffler’s official app to confirm batch registration, and compare the inner ring surface finish against known genuine samples. Counterfeit units often display shallow or blurred markings and use softer steel that shows scoring under fingernail pressure.
Q: Can I substitute a double-sealed needle roller bearing for the single-sealed NA4908-RSR?
A: Substitution depends on the housing geometry. The RSR suffix indicates a seal on one side only, typically because the opposite face is enclosed by the housing or an adjacent component. Installing a double-sealed variant in a space designed for single-side sealing may cause axial interference. Confirm the mounting envelope before approving any interchange.
Q: What cross-brand alternatives exist if the INA NA4908-RSR is unavailable?
A: Equivalent needle roller bearings from other major brands can be matched on bore, OD, width, seal type, and cage design — not just the base number. We provide a cross-reference comparison covering all alignment parameters so you can evaluate substitutes without risking dimensional or sealing mismatches.
Q: Is the NA4908-RSR relubricatable, or is it sealed for life?
A: The single lip seal on the NA4908-RSR is a contact seal designed to retain factory grease and exclude contamination. It is not intended for field relubrication. For applications requiring periodic grease replenishment, an open-type bearing with external sealing and relubrication ports would be more appropriate.
Q: What documentation comes with a bulk order of genuine INA needle roller bearings?
A: Each bulk shipment includes a Certificate of Conformity with batch traceability, dimensional inspection data, material certificates, and country-of-origin documentation. HS codes and import support paperwork are prepared per the destination country’s requirements.
Secure Your Genuine INA NA4908-RSR Supply
Submit your application parameters or OEM equipment number and we will return a matched quotation with full documentation and lead-time confirmation.
