NU218-NTN bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01

Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.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 NU218-NTN model number is decoded

NTN lists NU218 on the 90×160 mm envelope, 30 mm wide: a line-contact radial bearing with a pressed sheet-steel cage and a grease limiting speed of 4,300 r/min. On the NTN nameplate NU states which ring carries the ribs, which determines whether NU218 floats or locates; the numeric remainder is the ISO 15 series and 90 mm bore reference, not a fit or clearance instruction. Minimum radial load matters: an unloaded NU218 at high speed skids its rollers and smears the raceway; spring preload or the rotor weight typically covers the requirement in motors and pumps. Rating life at 169 kN C assumes clean oil and adequate film; the 20.3 kN Pu floor means contamination derating — not the C rating alone — governs adjusted life in dusty gearboxes. Mount the separable inner ring + roller assembly on the shaft first and slide the outer ring into the housing; never press the outer ring through the rollers of NU218.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Induction-heat the 90 mm inner ring (max 120 °C) and mount it before fitting the outer ring; the ring mass makes square guidance essential — driving through the rollers brinells the 160 mm raceway.
• Open NU218 units need application-supplied sealing and a defined lubricant schedule; film thickness is the first failure mode for line contact when viscosity drops at the 90 mm contact.
• If the shaft must be located both ways, do not use NU218 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
• Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 160 mm race brinells and releases as vibration within hours.
• Do not replace NU218 with a deep-groove ball bearing on rating alone: line contact gives 169 kN radial capacity but the bearing cannot carry the thrust duty a ball bearing can and misalignment tolerance is only 3–4 arc-minutes.
• The 169/178 kN ratings, 20.3 kN Pu and 2250 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU218 (standard execution); other makes sharing the ISO 15 envelope revise internal geometry without changing the order number, so keep the 2203E reference with the specification for critical drives.