RNAO45X55X17-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 RNAO45X55X17-XL model number is decoded

envelope 45×55×17 mm: 45 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 25.5 kN and C0 46 kN at the 45 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 6,300 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 0.57 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 83 g, just 0.09 g per mm² of projected 55×17 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 45 mm bore places this bearing in the medium band, where the 55 mm envelope already carries ratings in the tens of kilonewtons With no ribs the rollers can be arranged very freely in the 17 mm width, giving C 25.5 kN at only 55 mm outside diameter — the most compact radial unit in the HR1 needle section The shaft itself is the inner raceway: harden to 58–64 HRC and finish-grind to the catalogue journal tolerance, or the 46 kN static rating cannot be used The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 10,300 r/min limit. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 55 mm outside diameter and 25.5 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 45 mm seat, and in connecting-rod small ends the 83 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 17 mm width and the published 46 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. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.

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.
• Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.
• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.