NK17-16-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 NK17-16-XL model number is decoded

envelope 17×25×16 mm: 17 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 4.0 mm radial section packed with small-diameter needle rollers C is 13.5 kN and C0 15 kN at the 17 mm seat; the C/C0 ratio of 0.90 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 25 mm outside diameter the fatigue load limit Cur is 2.8 kN, the limiting speed 22,600 r/min and the thermal reference speed 15,300 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 0.79 kN/mm and per millimetre of width 0.84 kN/mm — the reason 16 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 23.7 g, just 0.06 g per mm² of projected 25×16 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 17 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces NK17/16-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality 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 17×25×16 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 25 mm outside diameter and 13.5 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 17 mm seat, and in two-stroke and compressor piston pins the 23.7 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 16 mm width and the published 15 kN static rating. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations. 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.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.
• 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.