NK65-25-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 NK65-25-XL model number is decoded

envelope 65×78×25 mm: 65 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 6.5 mm radial section packed with small-diameter needle rollers C is 50 kN and C0 98 kN at the 65 mm seat; the C/C0 ratio of 0.51 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 78 mm outside diameter the fatigue load limit Cur is 17 kN, the limiting speed 7,200 r/min and the thermal reference speed 4,500 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 0.77 kN/mm and per millimetre of width 2.00 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 221 g, just 0.11 g per mm² of projected 78×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 65 mm bore the 78 mm outside diameter and 25 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 7,200 r/min The thin 6.5 mm section makes the 221 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting Omitting the inner ring frees radial space — at a 65 mm shaft the outer diameter is only 78 mm and the width 25 mm, yet C is 50 kN The -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 7,200 r/min limit. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 78 mm outside diameter and 50 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 65 mm seat, and in hydraulic and pneumatic pump eccentrics the 221 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 25 mm width and the published 98 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. Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.

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.
• Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.
• 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.