NAO25X42X32-ZW-ASR1-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 NAO25X42X32-ZW-ASR1-XL model number is decoded

envelope 25×42×32 mm: 25 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.5 mm radial section packed with small-diameter needle rollers C is 45 kN and C0 67 kN at the 25 mm seat; the C/C0 ratio of 0.67 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 42 mm outside diameter the fatigue load limit Cur is 11.3 kN, the limiting speed 14,600 r/min and the thermal reference speed 7,800 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 1.80 kN/mm and per millimetre of width 1.41 kN/mm — the reason 32 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 190 g, just 0.14 g per mm² of projected 42×32 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 25 mm bore falls in the small band, the workhorse size for gearbox planetary positions, hydraulic pumps and general cam and linkage duty The inner ring gives a 25 mm plain bore inside the 42×32 mm envelope and the flangeless pack delivers C 45 kN — a frequent choice in gear change linkages and pumps With the inner ring fitted the shaft seat stays at normal bearing-shaft tolerance; C0 is 67 kN and Cur 11.3 kN for the 190 g unit X-life status (-XL) indicates the current Schaeffler premium execution at 25 mm bore; the 67 kN C0 rating reflects the improved rolling-contact geometry. The -ZW suffix denotes a double-row (zweireihig) needle roller and cage assembly: two roller rows share the 32 mm-wide envelope for higher capacity at the same bore. The ASR groove is particularly useful on double-row -ZW executions, feeding both rows evenly across the 42 mm outer ring. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 42 mm outside diameter and 45 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 25 mm seat, and in motorcycle and light-vehicle transmissions the 190 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 32 mm width and the published 67 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.
• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.