NKI17-20-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 NKI17-20-XL model number is decoded

envelope 17×29×20 mm: 17 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 6.0 mm radial section packed with small-diameter needle rollers C is 19.3 kN and C0 25.5 kN at the 17 mm seat; the C/C0 ratio of 0.76 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 29 mm outside diameter the fatigue load limit Cur is 4.5 kN, the limiting speed 20,600 r/min and the thermal reference speed 11,200 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 1.14 kN/mm and per millimetre of width 0.97 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 53.4 g, just 0.09 g per mm² of projected 29×20 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 NKI17/20-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 19.3 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 17 mm bore; the 25.5 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include hydraulic and pneumatic pump eccentrics, copying and printing machine mechanisms and agricultural machine pivots and linkages, where the 29 mm outside diameter and 19.3 kN dynamic rating match the duty. In hydraulic and pneumatic pump eccentrics the unit fits a compact 17 mm seat, and in copying and printing machine mechanisms the 53.4 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for agricultural machine pivots and linkages, relying on the 20 mm width and the published 25.5 kN static rating. 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. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• 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.
• Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.
• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.