RNA6909-ZW-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 RNA6909-ZW-XL model number is decoded

envelope 52×68×40 mm: 52 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.0 mm radial section packed with small-diameter needle rollers C is 79 kN and C0 127 kN at the 52 mm seat; the C/C0 ratio of 0.62 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 21.8 kN, the limiting speed 8,600 r/min and the thermal reference speed 4,950 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 1.52 kN/mm and per millimetre of width 1.98 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 338 g, just 0.12 g per mm² of projected 68×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 52 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons The hardness requirement is unforgiving: below about 58 HRC the 52 mm journal brinels under the 127 kN static rating, and roughness above raceway finish accelerates roller wear As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 21.8 kN Cur value. -ZW is the double-row needle-cage code; the two rows run on the same races and keep the unit separable and interchangeable with the single-row mounting space. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 68 mm outside diameter and 79 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 52 mm seat, and in small electric motor accessory drives the 338 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, relying on the 40 mm width and the published 127 kN static rating. Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Do not press an RNA/NK assembly in through the outer ring when mounting it on a shaft, and vice versa — rolling forces through the wrong ring bruises the raceways.
• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
• Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.