NK100-26-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 NK100-26-XL model number is decoded

envelope 100×120×26 mm: 100 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 86 kN and C0 146 kN at the 100 mm seat; the C/C0 ratio of 0.59 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 25.5 kN, the limiting speed 4,600 r/min and the thermal reference speed 3,150 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 0.86 kN/mm and per millimetre of width 3.31 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 515 g, just 0.17 g per mm² of projected 120×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 100 mm bore the 120 mm outside diameter and 26 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,600 r/min NK100/26-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 Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 25.5 kN Cur value. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 120 mm outside diameter and 86 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 100 mm seat, and in planetary gear bearings the 515 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 26 mm width and the published 146 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.