6208-RSR-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 6208-RSR-NTN model number is decoded

In the 6200-series (diameter series 2 of ISO 15) the last two digits encode the bore: 6208 carries bore code 08 = 40 mm. Outside diameter 80 mm and width 18 mm come from the ISO 15 boundary-dimensions general plan. Suffix -RSR denotes two low-friction non-contact elastomer seals; they keep coarse debris out with minimal drag but are not liquid-tight. For normal-load mounting with a rotating inner ring on a 40 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 non-contact seal suffix is LLB/LLF (catalogue number 6208LLB), mapped here from the industry-neutral -RSR spelling; speed capability matches the open bearing but it is not liquid-tight.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• A 40 mm shaft for 6208 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 62xx light series is the default general-purpose section at 40 mm bore; before upgrading to a 6308 for extra capacity, confirm the housing accepts a 80 mm OD and 18 mm width — it is not a drop-in swap.
• RSR low-friction seals on 6208-RSR-NTN run faster than contact-seal 6208-2RS but let fine dust and moisture past the non-contact lip; in dirty or wet duty specify 6208-2RS instead.
• The non-contact lip of 6208-RSR-NTN does not retain a lifetime grease fill the way a contact seal does; confirm the regreasing interval for the 40 mm bore position before relying on it as sealed-for-life.
• Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 18 mm-wide ring of 6208-RSR-NTN drags the lip and overheats it.
• Measure the shaft, do not trust the drawing: a 40 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 6208-RSR-NTN.
• NTN catalogues this low-friction non-contact seal as 6208LLB (suffix LLB), mapped here from the industry-neutral -RSR spelling. NTN rates its speed capability the same as the open bearing, but it is not liquid-tight — for wet or fine-dust duty step up to the LLU contact seal (industry-neutral -2RS).
• The 40 mm bore puts 6208 in NTN's general-purpose industrial range; the standard pressed-steel cage and CN clearance cover most electric-motor and 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 6700 r/min the grease limiting speed for 6208 covers medium-duty industrial drives; the open or shielded execution can run continuously at this speed with standard lithium-soap grease.
• At 32.5 kN dynamic load rating (C) and 17.8 kN static (C0), 1.24 kN fatigue load limit Cu, 6208 is a medium-load bearing suitable for most electric-motor and pump duty; the C0/C0r ratio matters for preloaded or thrust-loaded arrangements, so confirm the static safety factor with the NTN catalogue.
• At 366 g, 6208 requires a soft-jaw vise or arbor press for mounting — never hammer it onto the shaft, and support the opposite ring to avoid brinelling the raceways.
• The 40×80×18 mm envelope of 6208 gives a D/d ratio of 2.00 and 20.0 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 32.5/17.8 kN load ratings, 1.24 kN fatigue load limit Cu NTN lists the grease limiting speed at 6700 r/min for this designation; oil-mist or jet lubrication raises the ceiling but requires a sealed-housing review. and 366 g mass here are NTN Ball and Roller Bearings CAT.No.2203-3/E figures for 6208LLB on the 40×80×18 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6208 in a rated drive.
• Factory-fill grease in NTN sealed units is a general-duty lithium-soap grease; food-grade, low-temperature and high-temperature fills are request options at order time, because LLU/LLB units are not meant to be opened and re-greased in the field.
• Two NTN bearings of the same designation from different production lots can carry minor internal-geometry revisions; for paired or preloaded arrangements on one shaft, order a single lot through the NTN distributor.