RNAO40X50X17-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 RNAO40X50X17-XL model number is decoded

envelope 40×50×17 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 24.2 kN and C0 41.5 kN at the 40 mm seat; the C/C0 ratio of 0.58 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 6.6 kN, the limiting speed 11,500 r/min and the thermal reference speed 7,000 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 0.60 kN/mm and per millimetre of width 1.42 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 74 g, just 0.09 g per mm² of projected 50×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 40 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 17 mm width as a standard mounting space Flangeless races make this bearing purely radial — adjacent thrust washers or shoulders must locate the assembly axially and keep the rollers from walking off the journal Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 40×50×17 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 50 mm outside diameter and 24.2 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 40 mm seat, and in two-stroke and compressor piston pins the 74 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 17 mm width and the published 41.5 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. 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

• Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.
• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
• 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.