NKI35-20-TW-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 NKI35-20-TW-XL model number is decoded

envelope 35×50×20 mm: 35 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 32.5 kN and C0 48.5 kN at the 35 mm seat; the C/C0 ratio of 0.67 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 10.1 kN, the limiting speed 11,400 r/min and the thermal reference speed 6,900 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 0.93 kN/mm and per millimetre of width 1.63 kN/mm — the reason 20 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 122 g, just 0.12 g per mm² of projected 50×20 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 35 mm bore this is a mainstream industrial size — conveyor drives, winches and medium gearboxes use the 20 mm width as a standard mounting space NKI35/20-TW-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required The 7.5 mm section still holds a full needle pack; like all needle bearings it cannot tolerate angular misalignment, so shaft and housing axes must be parallel -XL means this is an X-life bearing — Schaeffler's upgraded performance level with smoother raceways, so the 32.5 kN C rating and longer nominal life come without an envelope change. Typical applications include agricultural machine pivots and linkages, hydraulic and pneumatic pump eccentrics and textile machine heald and cam shafts, where the 50 mm outside diameter and 32.5 kN dynamic rating match the duty. In agricultural machine pivots and linkages the unit fits a compact 35 mm seat, and in hydraulic and pneumatic pump eccentrics the 122 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for textile machine heald and cam shafts, relying on the 20 mm width and the published 48.5 kN static rating. On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.
• Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.
• 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.