NKI40-30-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 NKI40-30-TV-XL model number is decoded

envelope 40×55×30 mm: 40 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 7.5 mm radial section packed with small-diameter needle rollers C is 52 kN and C0 103 kN at the 40 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 55 mm outside diameter the fatigue load limit Cur is 19.5 kN, the limiting speed 10,200 r/min and the thermal reference speed 5,400 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 1.30 kN/mm and per millimetre of width 1.73 kN/mm — the reason 30 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 216 g, just 0.13 g per mm² of projected 55×30 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 40 mm bore places this bearing in the medium band, where the 55 mm envelope already carries ratings in the tens of kilonewtons Cur 19.5 kN, limiting speed 10,200 r/min, reference speed 5,400 r/min — the inner ring adds a few grams (total 216 g) but removes the hardening requirement This is the choice for OEM production on soft shafts: machine the 40 mm seat to the recommended tolerance, fit the bearing, and let the inner ring provide the precision raceway X-life status (-XL) indicates the current Schaeffler premium execution at 40 mm bore; the 103 kN C0 rating reflects the improved rolling-contact geometry. -TV denotes the PA66 cage: light, quiet and self-lubricating in dry-running moments, but limited by the polymer's continuous-temperature ceiling well below the ring steel's. Typical applications include connecting-rod small ends, textile machine heald and cam shafts and motorcycle and light-vehicle transmissions, where the 55 mm outside diameter and 52 kN dynamic rating match the duty. In connecting-rod small ends the unit fits a compact 40 mm seat, and in textile machine heald and cam shafts the 216 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for motorcycle and light-vehicle transmissions, relying on the 30 mm width and the published 103 kN static rating. Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone. 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

• Open ends draw contamination directly onto the needles; specify sealed or shielded positions in dusty environments rather than relying on grease alone.
• 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.
• Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.