NA6909-ZW-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 NA6909-ZW-XL model number is decoded

envelope 45×68×40 mm: 45 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 11.5 mm radial section packed with small-diameter needle rollers C is 79 kN and C0 127 kN at the 45 mm seat; the C/C0 ratio of 0.62 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 68 mm outside diameter the fatigue load limit Cur is 21.8 kN, the limiting speed 8,600 r/min and the thermal reference speed 4,750 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 1.76 kN/mm and per millimetre of width 1.98 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 495 g, just 0.18 g per mm² of projected 68×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 45 mm bore places this bearing in the medium band, where the 68 mm envelope already carries ratings in the tens of kilonewtons Reading the NA69 prefix: machined-ring needle bearing with inner ring, two roller rows, capable of pure radial load at 79 kN C NA6909-ZW-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 X-life status (-XL) indicates the current Schaeffler premium execution at 45 mm bore; the 127 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 40 mm-wide envelope for higher capacity at the same bore. Typical applications include two-stroke and compressor piston pins, motorcycle and light-vehicle transmissions and rocker arms and valve trains, where the 68 mm outside diameter and 79 kN dynamic rating match the duty. In two-stroke and compressor piston pins the unit fits a compact 45 mm seat, and in motorcycle and light-vehicle transmissions the 495 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for rocker arms and valve trains, relying on the 40 mm width and the published 127 kN static rating. Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately. 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

• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.
• Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.
• On reciprocating duty ensure the stroke rotates the full needle set, or brinelling occurs at the same roller positions.