NK73-35-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 NK73-35-XL model number is decoded

envelope 73×90×35 mm: 73 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 85 kN and C0 156 kN at the 73 mm seat; the C/C0 ratio of 0.54 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 90 mm outside diameter the fatigue load limit Cur is 27.5 kN, the limiting speed 6,300 r/min and the thermal reference speed 4,050 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 1.16 kN/mm and per millimetre of width 2.43 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 428 g, just 0.14 g per mm² of projected 90×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages with a 73 mm bore this is a heavy-industrial bearing: 428 g of stiff ring and roller set, specified where rigidity matters more than speed The thin 8.5 mm section makes the 428 g bearing sensitive to seat geometry — a tapered or lobed journal preloads part of the needle set and shows up as local pitting This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces As an X-life (-XL) bearing it benefits from the optimised surface finish that reduces friction and raises the fatigue strength behind the 27.5 kN Cur value. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 90 mm outside diameter and 85 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 73 mm seat, and in hydraulic and pneumatic pump eccentrics the 428 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 35 mm width and the published 156 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. 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.

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.
• 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.
• 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.