NA4908-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 NA4908-XL model number is decoded

envelope 40×62×22 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.0 mm radial section packed with small-diameter needle rollers C is 48.5 kN and C0 67 kN at the 40 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 5,000 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 1.21 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 230 g, just 0.17 g per mm² of projected 62×22 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 22 mm width as a standard mounting space The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 67 kN C0 rating still assumes full rigid support under both rings As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 11.7 kN Cur value. Typical applications include planetary gear bearings, small electric motor accessory drives and gearbox selector and change linkages, where the 62 mm outside diameter and 48.5 kN dynamic rating match the duty. In planetary gear bearings the unit fits a compact 40 mm seat, and in small electric motor accessory drives the 230 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for gearbox selector and change linkages, 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. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.

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