NA4924-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 NA4924-XL model number is decoded

envelope 120×165×45 mm: 120 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 22.5 mm radial section packed with small-diameter needle rollers C is 205 kN and C0 390 kN at the 120 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 165 mm outside diameter the fatigue load limit Cur is 65 kN, the limiting speed 3,400 r/min and the thermal reference speed 2,160 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 1.71 kN/mm and per millimetre of width 4.56 kN/mm — the reason 45 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 2.86 kg (2860 g), just 0.39 g per mm² of projected 165×45 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 120 mm bore the 165 mm outside diameter and 45 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 3,400 r/min The 22.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel This is the choice for OEM production on soft shafts: machine the 120 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 65 kN Cur value. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 165 mm outside diameter and 205 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 120 mm seat, and in planetary gear bearings the 2.86 kg mass is part of the rotor inertia calculation. Designers also specify it for copying and printing machine mechanisms, relying on the 45 mm width and the published 390 kN static rating. 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.

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