NK40-20-TV-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 NK40-20-TV-XL model number is decoded

envelope 40×50×20 mm: 40 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 5.0 mm radial section packed with small-diameter needle rollers C is 33.5 kN and C0 56 kN at the 40 mm seat; the C/C0 ratio of 0.60 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 50 mm outside diameter the fatigue load limit Cur is 10 kN, the limiting speed 11,400 r/min and the thermal reference speed 6,500 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 0.84 kN/mm and per millimetre of width 1.68 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 78 g, just 0.08 g per mm² of projected 50×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 50 mm envelope already carries ratings in the tens of kilonewtons 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 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 -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 33.5 kN C rating and longer nominal life come without an envelope change. With the -TV polyamide cage the rollers are positively separated, so the 40 mm bearing suits continuous rotation rather than the slow oscillating duty where cageless packs are chosen. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 50 mm outside diameter and 33.5 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 40 mm seat, and in planetary gear bearings the 78 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 20 mm width and the published 56 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.