NA4912-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 NA4912-XL model number is decoded

envelope 60×85×25 mm: 60 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 12.5 mm radial section packed with small-diameter needle rollers C is 68 kN and C0 108 kN at the 60 mm seat; the C/C0 ratio of 0.63 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 85 mm outside diameter the fatigue load limit Cur is 19.1 kN, the limiting speed 6,700 r/min and the thermal reference speed 3,700 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 1.13 kN/mm and per millimetre of width 2.72 kN/mm — the reason 25 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 426 g, just 0.20 g per mm² of projected 85×25 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 60 mm bore marks the medium range: mounting forces and fits become critical, and the 426 g mass calls for proper induction or press tooling rather than hand fitting The inner ring is separable, so the outer-ring/roller assembly can be pressed into the housing first; the 108 kN C0 rating still assumes full rigid support under both rings NA4912-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 -XL suffix is the Schaeffler X-life mark: interchangeable envelope with the basic bearing, but higher load capacity and lower running temperature at the 6,700 r/min limit. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 85 mm outside diameter and 68 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 60 mm seat, and in two-stroke and compressor piston pins the 426 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 25 mm width and the published 108 kN static rating. 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.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• 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.
• Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.