6004-2RS-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 6004-2RS-NTN model number is decoded

In the 6000-series (diameter series 0 of ISO 15) the last two digits encode the bore: 6004 carries bore code 04 = 20 mm. Outside diameter 42 mm and width 12 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 20 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 6004LLU (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

• A 20 mm shaft for 6004 should be finished to Ra ≤ 1.6 µm with square seating faces; at this bore a scored or oval journal shows up directly as running noise and early raceway damage.
• The 60xx extra-light section at 20 mm bore uses a smaller 42 mm OD than a 6204; load ratings are lower, so do not replace a failed 62-series bearing with a 60-series without re-rating the load.
• Contact seals add drag and heat: 6004-2RS-NTN runs slower and cooler-limited than the open 6004; 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 6004-2RS: 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.
• The housing bore for the 42 mm OD should be round within IT7; an oval bore pinches the outer ring of 6004-2RS-NTN and shows up later as two-point loaded raceway wear.
• Grease compatibility is not guaranteed between fills: mixing lithium and polyurea thickeners in a 6000-series position can soften the mixture and leak — clean out the old fill before switching grease types.
• NTN catalogues the contact-sealed version as 6004LLU (suffix LLU), 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 20 mm bore puts 6004 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 11000 r/min the grease limiting speed for 6004 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.
• NTN rates 6004 at 10.4 kN dynamic (C) and 5.05 kN static (C0), 0.35 kN fatigue load limit Cu; this light-to-medium rating suits fractional-horsepower drives and instruments — for conveying or gearbox duty with shock loads, verify the equivalent dynamic load stays well below C.
• At 69 g, 6004 is light enough for hand assembly but should be pressed on with a fitting sleeve against the inner ring; do not strike the outer ring or cage with a hammer.
• The 20×42×12 mm envelope of 6004 gives a D/d ratio of 2.10 and 11.0 mm radial section height — a heavy section built for high-load, lower-speed duty; specifying it in a high-rpm motor generates excess heat and shortens grease life, so prefer a 62/63-series there.
• The 10.4/5.05 kN load ratings, 0.35 kN fatigue load limit Cu NTN lists the grease limiting speed at 11000 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 69 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6004LLU on the 20×42×12 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6004 in a rated drive.
• Order the C3 internal-clearance version (6004 with C3 after the seal code) when the shaft fit is tight or the shaft-to-housing temperature gradient exceeds roughly 10 °C — the residual clearance after mounting, not the catalogue CN figure, decides service life.
• Standard catalogue stock of 6004 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.