RNA6904-XL bearing: complete specifications & equivalents

Specification table

Source: catalog reference (HR1 2026-09-25) · extracted 2026-09-30

Parameters extracted from the official FAG Rolling Bearings catalogue (HR1 2026-09-25); FAG® is a trademark of Schaeffler Technologies AG & Co. KG, used here for identification only — mpnbase is not an authorized FAG/Schaeffler distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at schaeffler.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the RNA6904-XL model number is decoded

envelope 25×37×30 mm: 25 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 40.5 kN and C0 51 kN at the 25 mm seat; the C/C0 ratio of 0.79 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 37 mm outside diameter the fatigue load limit Cur is 9.2 kN, the limiting speed 16,900 r/min and the thermal reference speed 9,500 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.62 kN/mm and per millimetre of width 1.35 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 100 g, just 0.09 g per mm² of projected 37×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 25 mm bore the 30 mm width and 40.5 kN C rating suit high-cycle industrial machinery rather than instrument duty The hardness requirement is unforgiving: below about 58 HRC the 25 mm journal brinels under the 51 kN static rating, and roughness above raceway finish accelerates roller wear Reading the RNA69 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 40.5 kN C rating and longer nominal life come without an envelope change. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 37 mm outside diameter and 40.5 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 25 mm seat, and in two-stroke and compressor piston pins the 100 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 30 mm width and the published 51 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.
• Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.