61803-2RS-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 61803-2RS-NSK model number is decoded

61803-2RS is closed by two contacting elastomer lips over a lifetime grease fill; the lips add friction, so the speed ceiling sits below the open execution. 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's contact-seal catalogue number is 6803DD (suffix DDU), mapped here from the industry-neutral -2RS spelling; it is greased for life and the contacting lip lowers the speed ceiling versus the open bearing.

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.
• Only 4.5 mm of radial section separates bore and OD on the 618xx series at 17 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6217.
• Contact seals add drag and heat: 61803-2RS-NSK runs slower and cooler-limited than the open 61803; rubber lips are generally limited to roughly 80–110 °C continuous depending on grease, and C3 clearance is the common hot-duty choice.
• Never wash a sealed 61803-2RS-NSK in solvent or press it home via the outer ring; solvent destroys the grease thickener and mounting force through the seal deforms the lip.
• Grease compatibility is not guaranteed between fills: mixing lithium and polyurea thickeners in a 61800-series position can soften the mixture and leak — clean out the old fill before switching grease types.
• Assign fits by which ring rotates: an interference shaft fit for a rotating inner ring; if the outer ring rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
• NSK catalogues the contact-sealed version as 6803DD (suffix DDU), mapped here from the industry-neutral -2RS spelling; it is greased for life and the contacting lip lowers the speed ceiling versus the open bearing. NSK's DDU lip design is single-lip contact, so grease life is longer than VV but drag torque is higher.
• 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 6803DD 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.
• 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.
• Standard P0 runout from NSK is adequate up to the catalogue limiting speed on ground shaft seats; spindle or instrument positions should specify P6/P5 accuracy explicitly — it is a different order code, not a sorting of standard stock.