61803-ZZ-NSK bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NSK Rolling Bearings E1103 Part C) · extracted 2026-09-24

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 61803-ZZ-NSK model number is decoded

61803-ZZ carries two non-contact sheet-steel shields that hold the factory grease in and keep coarse debris out; they do not seal against liquids. Within the extra-thin 618xx section (diameter series 8 of ISO 15), multiplying bore code 17 by five gives the 17 mm bore; the 26 mm outside diameter and 5 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 17 mm shaft under normal load, catalogue practice seats it on a j5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. NSK catalogue order number: 6803ZZ (suffix ZZ), two non-contact steel shields, mapped here from the industry-neutral -ZZ spelling.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Mount this 17 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
• The 618xx thin section at 17 mm bore has only a 4.5 mm radial section height: it saves space but is highly sensitive to misalignment, shaft deflection and shock loads — verify shaft stiffness before choosing it over a 6217.
• ZZ shields are non-contact: 61803-ZZ-NSK blocks chips and coarse dust but is not waterproof — do not install it expecting a pressure-wash seal, step up to 61803-2RS for that.
• Shielded 61803-ZZ-NSK units are typically greased for life; prying the shields out for regreasing usually bends them and leaves a gap that throws grease in service.
• Measure the shaft, do not trust the drawing: a 17 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 61803-ZZ-NSK.
• Never mix components between two 61803-ZZ-NSK units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
• NSK catalogues the shielded version as 6803ZZ — suffix ZZ, two non-contact steel shields. The industry-neutral page spelling is -ZZ; quote the NSK order number when buying through an NSK channel.
• At 17 mm bore the 61803 sits in NSK's small-bore range; NSK ships these sizes with a pressed-steel cage and P0 tolerance as standard, and NSK's EA (extra-precision) or P5 class is a special-order upgrade for spindle duty — do not assume catalogue P0 figures hold for instrument use without an NSK engineering check.
• At 2.89 kN dynamic load rating (C) and 1.57 kN static (C0), 61803 is a light-load NSK bearing: the L10 life at catalogue C is short above a few kN of equivalent load, so size up to a 62-series on the same bore if the application sees shock or frequent starts.
• At only 7 g, 61803 is a lightweight NSK bearing that can be handled by hand; still, press it onto the shaft with a sleeve against the inner ring — never through the balls or outer ring.
• The 17×26×5 mm envelope of 61803 gives a D/d ratio of 1.53 and 4.5 mm radial section height — this NSK thin section saves space but is sensitive to misalignment and shock; confirm the housing stays round within IT7 and the shaft does not deflect past the raceway contact angle under load.
• The 2.89/1.57 kN load ratings, mass 7 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6803ZZ on the 17×26×5 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61803 in a rated drive. NSK does not tabulate reference or limiting speeds in the E1103 Part C dimension tables used for this page — consult NSK's separate speed-rating tables before high-speed service.
• When replacing a failed unit, inspect the shaft and housing seats before fitting the new 61803 — a new bearing pressed onto a worn or oval seat reproduces the original failure mode in a fraction of its expected life.
• NSK's VV non-contact seal keeps frictional torque close to the open 61803; in motor duty where heat build-up matters, VV is the usual compromise between debris protection and speed capability.