NKI85-36-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 NKI85-36-XL model number is decoded

envelope 85×115×36 mm: 85 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 121 kN and C0 223 kN at the 85 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 115 mm outside diameter the fatigue load limit Cur is 40.5 kN, the limiting speed 4,850 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 1.42 kN/mm and per millimetre of width 3.36 kN/mm — the reason 36 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.04 kg (1040 g), just 0.25 g per mm² of projected 115×36 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 85 mm bore this is a heavy-industrial bearing: 1.04 kg of stiff ring and roller set, specified where rigidity matters more than speed Cur 40.5 kN, limiting speed 4,850 r/min, reference speed 2,950 r/min — the inner ring adds a few grams (total 1040 g) but removes the hardening requirement Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 121 kN C X-life status (-XL) indicates the current Schaeffler premium execution at 85 mm bore; the 223 kN C0 rating reflects the improved rolling-contact geometry. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 115 mm outside diameter and 121 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 1.04 kg mass is part of the rotor inertia calculation. Designers also specify it for small electric motor accessory drives, relying on the 36 mm width and the published 223 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. 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

• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.
• 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.
• Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.