RNAO40X55X20-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 RNAO40X55X20-XL model number is decoded

envelope 40×55×20 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 37 kN and C0 57 kN at the 40 mm seat; the C/C0 ratio of 0.65 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 9.1 kN, the limiting speed 11,300 r/min and the thermal reference speed 6,600 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 0.93 kN/mm and per millimetre of width 1.85 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 145 g, just 0.13 g per mm² of projected 55×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 40 mm bore marks the medium range: mounting forces and fits become critical, and the 145 g mass calls for proper induction or press tooling rather than hand fitting Cur 9.1 kN and speeds up to 11,300 r/min suit planetary gears, connecting rods and pump eccentrics where space is dictated by the shaft diameter 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 X-life status (-XL) indicates the current Schaeffler premium execution at 40 mm bore; the 57 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 55 mm outside diameter and 37 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 40 mm seat, and in copying and printing machine mechanisms the 145 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 57 kN static rating. 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.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• 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.
• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.