NK68-35-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 NK68-35-XL model number is decoded

envelope 68×82×35 mm: 68 mm seat is the hardened and ground shaft journal itself — there is no inner ring, with a thin 7.0 mm radial section packed with small-diameter needle rollers C is 70 kN and C0 139 kN at the 68 mm seat; the C/C0 ratio of 0.50 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 82 mm outside diameter the fatigue load limit Cur is 26 kN, the limiting speed 6,800 r/min and the thermal reference speed 4,350 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 1.03 kN/mm and per millimetre of width 2.00 kN/mm — the reason 35 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 338 g, just 0.12 g per mm² of projected 82×35 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 68 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery NK68/35-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 This bearing accepts axial displacement between shaft and housing because the rollers rotate on the free journal; it locates nothing axially and must be flanked by guide faces 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 6,800 r/min limit. Typical applications include gearbox selector and change linkages, planetary gear bearings and copying and printing machine mechanisms, where the 82 mm outside diameter and 70 kN dynamic rating match the duty. In gearbox selector and change linkages the unit fits a compact 68 mm seat, and in planetary gear bearings the 338 g mass keeps unbalanced forces low in fast linkages. Designers also specify it for copying and printing machine mechanisms, relying on the 35 mm width and the published 139 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. 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

• Needle bearings are pure-radial units — any thrust must be taken by separate washers or an adjacent bearing, especially on flangeless RNAO/NAO.
• Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.
• 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.