NK105-26-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 NK105-26-XL model number is decoded

envelope 105×125×26 mm: 105 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 10.0 mm radial section packed with small-diameter needle rollers C is 89 kN and C0 155 kN at the 105 mm seat; the C/C0 ratio of 0.57 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 125 mm outside diameter the fatigue load limit Cur is 27 kN, the limiting speed 4,400 r/min and the thermal reference speed 3,050 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 0.85 kN/mm and per millimetre of width 3.42 kN/mm — the reason 26 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 540 g, just 0.17 g per mm² of projected 125×26 mm envelope, which keeps unbalanced forces low in fast-actuating linkages at 105 mm bore the 125 mm outside diameter and 26 mm width target rolling stands, construction machinery and heavy gearboxes; the limiting speed drops to 4,400 r/min Reading the NK prefix: a machined (not drawn-cup) outer ring with the needle complement; an inner ring from the IR series can be added later if the shaft cannot be hardened NK105/26-XL has no inner ring: the needle rollers run directly on the shaft journal, so the seat must be hardened (58–64 HRC) and ground to bearing raceway quality 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 4,400 r/min limit. Typical applications include motorcycle and light-vehicle transmissions, connecting-rod small ends and two-stroke and compressor piston pins, where the 125 mm outside diameter and 89 kN dynamic rating match the duty. In motorcycle and light-vehicle transmissions the unit fits a compact 105 mm seat, and in connecting-rod small ends the 540 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for two-stroke and compressor piston pins, relying on the 26 mm width and the published 155 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.