61805-2RS-NTN bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)) · extracted 2026-09-25

Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203-3/E (2024)); 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 61805-2RS-NTN model number is decoded

In the 61800-series (diameter series 8 of ISO 15) the last two digits encode the bore: 61805 carries bore code 05 = 25 mm. Outside diameter 37 mm and width 7 mm come from the ISO 15 boundary-dimensions general plan. Suffix -2RS denotes two contact-type elastomer seals over a lifetime grease fill; the sealing lips add drag compared with open or shielded versions. For normal-load mounting with a rotating inner ring on a 25 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. NTN's contact-seal catalogue number is 6805JRLLU (suffix LLU, or LLH low-torque variant), mapped here from the industry-neutral -2RS spelling; the contacting lip lowers the speed ceiling versus the open bearing.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Sizes around 25 mm bore are normally pressed on cold with a sleeve against the inner-ring face; the press force must never route through the outer ring or the balls of 61805-2RS-NTN.
• Only 6.0 mm of radial section separates bore and OD on the 618xx series at 25 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6205.
• Contact seals add drag and heat: 61805-2RS-NTN runs slower and cooler-limited than the open 61805; rubber lips are generally limited to roughly 80–110 °C continuous depending on grease, and C3 clearance is the common hot-duty choice.
• Heat is the enemy of the sealed 61805-2RS: sustained running near the lip temperature limit hardens the rubber, after which grease escapes and dirt tracks in — watch the housing temperature in hot drives.
• Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 7 mm-wide ring of 61805-2RS-NTN drags the lip and overheats it.
• A 25 mm bore listing showing the right d/D/B but no standard or precision-class reference may be a loose-tolerance import; measure bore/OD spread before fitting it to a machined shaft.
• NTN catalogues the contact-sealed version as 6805JRLLU (suffix RLLU), 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.
• The 25 mm bore puts 61805 in NTN's light industrial range; the standard pressed-steel cage and CN clearance cover most fractional-horsepower motor and small-pump duty, but for continuous high-speed use specify the LLH low-torque seal (not LLU) and confirm the housing allows the listed limiting speed.
• At 10000 r/min the grease limiting speed for 61805 covers most general-purpose industrial drives; the contact seal (LLU) is the main speed limiter here — for continuous operation above 80% of this figure use the open variant with an external labyrinth seal and oil bath.
• At 4.75 kN dynamic load rating (C) and 2.95 kN static (C0), 0.21 kN fatigue load limit Cu, 61805 is a light-load 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 22 g, 61805 is a lightweight 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 25×37×7 mm envelope of 61805 gives a D/d ratio of 1.48 and 6.0 mm radial section height — this 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 4.75/2.95 kN load ratings, 0.21 kN fatigue load limit Cu NTN lists the grease limiting speed at 10000 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 22 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6805JRLLU on the 25×37×7 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61805 in a rated drive.
• NTN's pressed-steel cage (no cage suffix) is the quiet standard for this size; for sustained running close to the limiting speed or for heavy shock duty, ask the NTN channel whether a machined-cage execution of 61805 is listed.
• Standard catalogue stock of 61805 is the general-purpose execution; for low-noise motor duty NTN offers low-torque seal and special-grease variants in this size class, which are separate order numbers.