NAO40X55X17-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 NAO40X55X17-XL model number is decoded

envelope 40×55×17 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 25.5 kN and C0 46 kN at the 40 mm seat; the C/C0 ratio of 0.55 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 7.3 kN, the limiting speed 10,300 r/min and the thermal reference speed 5,900 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 0.64 kN/mm and per millimetre of width 1.50 kN/mm — the reason 17 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 127 g, just 0.14 g per mm² of projected 55×17 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 The single needle row fills the thin section, with limiting speed 10,300 r/min and reference speed 5,900 r/min Flangeless NAO bearings tolerate ring displacement during mounting but not misalignment in operation — the 7.5 mm section is too thin to compensate for tilted seats 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 40×55×17 mm envelope. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 55 mm outside diameter and 25.5 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 40 mm seat, and in planetary gear bearings the 127 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 17 mm width and the published 46 kN static rating. 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. 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.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• 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.
• 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.
• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.