NKI90-26-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 NKI90-26-XL model number is decoded

envelope 90×120×26 mm: 90 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 86 kN and C0 146 kN at the 90 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 2,950 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 0.96 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 778 g, just 0.25 g per mm² of projected 120×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 90 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery Cur 25.5 kN, limiting speed 4,600 r/min, reference speed 2,950 r/min — the inner ring adds a few grams (total 778 g) but removes the hardening requirement The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 146 kN C0 rating still assumes full rigid support under both rings -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 86 kN C rating and longer nominal life come without an envelope change. Typical applications include small electric motor accessory drives, rocker arms and valve trains and planetary gear bearings, where the 120 mm outside diameter and 86 kN dynamic rating match the duty. In small electric motor accessory drives the unit fits a compact 90 mm seat, and in rocker arms and valve trains the 778 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for planetary gear bearings, relying on the 26 mm width and the published 146 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. 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

• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
• 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.
• 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.