RNAO55X68X20-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 RNAO55X68X20-XL model number is decoded

envelope 55×68×20 mm: 55 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 32 kN and C0 66 kN at the 55 mm seat; the C/C0 ratio of 0.48 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 10.9 kN, the limiting speed 8,500 r/min and the thermal reference speed 5,400 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 0.58 kN/mm and per millimetre of width 1.60 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 166 g, just 0.12 g per mm² of projected 68×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 55 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons Reading RNAO: O denotes the ribless (open-sided) race design; the single roller row runs directly between ground shaft and housing bore 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 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 55×68×20 mm envelope. Typical applications include textile machine heald and cam shafts, agricultural machine pivots and linkages and connecting-rod small ends, where the 68 mm outside diameter and 32 kN dynamic rating match the duty. In textile machine heald and cam shafts the unit fits a compact 55 mm seat, and in agricultural machine pivots and linkages the 166 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for connecting-rod small ends, relying on the 20 mm width and the published 66 kN static rating. 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.

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.
• 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.
• 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.