NA4917-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 NA4917-XL model number is decoded

envelope 85×120×35 mm: 85 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 17.5 mm radial section packed with small-diameter needle rollers C is 125 kN and C0 237 kN at the 85 mm seat; the C/C0 ratio of 0.53 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 120 mm outside diameter the fatigue load limit Cur is 42.5 kN, the limiting speed 4,600 r/min and the thermal reference speed 2,650 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 1.47 kN/mm and per millimetre of width 3.57 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.25 kg (1250 g), just 0.30 g per mm² of projected 120×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 85 mm bore the 120 mm outside diameter and 35 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,600 r/min The 17.5 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 Cur 42.5 kN, limiting speed 4,600 r/min, reference speed 2,650 r/min — the inner ring adds a few grams (total 1250 g) but removes the hardening requirement As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 42.5 kN Cur value. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 120 mm outside diameter and 125 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 85 mm seat, and in two-stroke and compressor piston pins the 1.25 kg mass is part of the rotor inertia calculation. Designers also specify it for small electric motor accessory drives, relying on the 35 mm width and the published 237 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. 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

• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.
• 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.
• 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.