61838-RSR 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 61838-RSR model number is decoded

In the 61800-series (diameter series 8 of ISO 15) the last two digits encode the bore: 61838 carries bore code 38 = 190 mm. Outside diameter 240 mm and width 24 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 190 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. NSK's non-contact seal suffix is VV (catalogue number 6838VV), mapped here from the industry-neutral -RSR spelling; speed capability is close to the open bearing but VV is not liquid-tight.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Large bores like the 190 mm of 61838-RSR demand clean, burr-free seats; one raised burr under a ring this size cocks the bearing and concentrates load at the raceway edge, cutting life drastically.
• Only 25.0 mm of radial section separates bore and OD on the 618xx series at 190 mm: ring flex from clamping or an oval housing bore transfers straight into raceway stress, so seat roundness matters more here than on a 6238.
• RSR low-friction seals on 61838-RSR run faster than contact-seal 61838-2RS but let fine dust and moisture past the non-contact lip; in dirty or wet duty specify 61838-2RS instead.
• The low-drag lip of 61838-RSR barely touches the inner ring; after long shelf storage the grease can separate, so rotate the rings by hand and confirm smooth, silent running before fitting.
• Shaft and housing fillets must clear the bearing chamfer so the 24 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
• Vibration during standstill brinells the raceways of a 190 mm bearing at ball spacing; if the machine sits idle next to running equipment, turn the shaft over periodically or isolate the arrangement.
• NSK catalogues this low-friction non-contact seal as 6838VV (suffix VV), mapped here from the industry-neutral -RSR spelling. NSK rates its speed capability close to the open bearing, but VV is not liquid-tight — for wet or fine-dust duty step up to the DDU contact seal (industry-neutral -2RS).
• The 190 mm bore places 61838 in NSK's large-size range; at these diameters the pressed-steel cage is speed-limited and NSK commonly supplies a machined brass cage (suffix M) as an option. Verify cage material and relubrication interval with the NSK distributor, and do not extrapolate small-bore speed ratings to this size.
• At 80.5 kN dynamic load rating (C) and 93.5 kN static (C0), 61838 is a heavy-load NSK bearing for industrial gearboxes and large conveyors; NSK expects a machined brass cage (suffix M) at this rating for shock duty, and the static C0 must be checked against any mounting or lifting loads.
• At 2530 g (2.5 kg), 61838 needs mechanical handling for mounting; NSK recommends induction heating the inner ring (max 120 °C) rather than pressing cold, and a lifting eye if the housing is pre-assembled.
• The 190×240×24 mm envelope of 61838 gives a D/d ratio of 1.26 and only 25.0 mm radial section height — this is an ultra-thin section in NSK's E1103 catalogue where shaft deflection and housing ovality directly load the ball-raceway contact; verify shaft stiffness (target deflection under 0.05 mm) before specifying it over a 62-series.
• The 80.5/93.5 kN load ratings, mass 2530 g here are NSK Rolling Bearings E1103 Part C catalogue figures for 6838VV on the 190×240×24 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61838 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 supplies its sealed units pre-greased for general duty between roughly -10 and +110 °C; low-temperature, food-grade and high-temperature fills are special executions — ask at order time, because DDU/VV units are not designed to be opened and repacked.
• When replacing a failed unit, inspect the shaft and housing seats before fitting the new 61838 — a new bearing pressed onto a worn or oval seat reproduces the original failure mode in a fraction of its expected life.