NAO12X28X12-IS1-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 NAO12X28X12-IS1-XL model number is decoded

envelope 12×28×12 mm: 12 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 8.0 mm radial section packed with small-diameter needle rollers C is 13 kN and C0 12.5 kN at the 12 mm seat; the C/C0 ratio of 1.04 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 28 mm outside diameter the fatigue load limit Cur is 2.25 kN, the limiting speed 22,900 r/min and the thermal reference speed 14,300 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 1.08 kN/mm and per millimetre of width 1.08 kN/mm — the reason 12 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 40 g, just 0.12 g per mm² of projected 28×12 mm envelope, which keeps unbalanced forces low in fast-actuating linkages 12 mm bore and only 40 g: the smallest sizes demand accurate shaft geometry, because the 8.0 mm section leaves no tolerance for a soft or tapered seat The single needle row fills the thin section, with limiting speed 22,900 r/min and reference speed 14,300 r/min X-life status (-XL) indicates the current Schaeffler premium execution at 12 mm bore; the 12.5 kN C0 rating reflects the improved rolling-contact geometry. -IS1 is the inner-ring lube option; it changes nothing in the 12×28×12 mm envelope but requires a matching oilway in the shaft. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 28 mm outside diameter and 13 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 12 mm seat, and in two-stroke and compressor piston pins the 40 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for small electric motor accessory drives, relying on the 12 mm width and the published 12.5 kN static rating. 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. 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

• 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.
• 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.