RNA4908-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 RNA4908-XL model number is decoded

envelope 48×62×22 mm: 48 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 48.5 kN and C0 67 kN at the 48 mm seat; the C/C0 ratio of 0.72 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 62 mm outside diameter the fatigue load limit Cur is 11.7 kN, the limiting speed 9,200 r/min and the thermal reference speed 5,300 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 1.01 kN/mm and per millimetre of width 2.20 kN/mm — the reason 22 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 140 g, just 0.10 g per mm² of projected 62×22 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 48 mm bore places this bearing in the medium band, where the 62 mm envelope already carries ratings in the tens of kilonewtons Reading the RNA49 prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened 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 48×62×22 mm envelope. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 62 mm outside diameter and 48.5 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 48 mm seat, and in textile machine heald and cam shafts the 140 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 22 mm width and the published 67 kN static rating. 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.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• 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.
• Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.