61901-2RS-FAG bearing: complete specifications & equivalents

The 61901-2RS-FAG is a ISO 15 radial bearing sized 12 x 24 x 6 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.

Bearing dimension schematic Front view shows outer diameter D and bore d; side section shows width B. D = 24 mm d = 12 B = 6 mm side section front view
Principal dimensions: bore d 12 mm, outer diameter D 24 mm, width B 6 mm. Schematic, not to scale.

Specification table

ParameterValue
Brand FAG
Bore diameter d 12 mm
Outer diameter D 24 mm
Width B 6 mm
Material GCr15
Seal / shield 2RS
Internal clearance CN
Tolerance class P0
Cage steel
Basic dynamic load rating C 2.89 kN
Basic static load rating C0 1.46 kN
Limiting speed (mechanical) 16700 rpm
Mass 12 g
Manufacturer designation FAG 61901-2RSR
Standard ISO 15
Catalog version HR 1 Rolling Bearings (Jan 2020)
Last verified 2026-09-25

Source: catalog reference (HR 1 Rolling Bearings (Jan 2020)) · extracted 2026-09-25

Parameters extracted from the official FAG Rolling Bearings catalogue (HR 1 Rolling Bearings (Jan 2020)); FAG® is a trademark of Schaeffler Technologies AG & Co. KG, used here for identification only — mpnbase is not an authorized FAG/Schaeffler distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at schaeffler.com.

Dimensions in inches & 61900-series range

Bore d0.472 in
Outer diameter D0.945 in
Width B0.236 in
ISO bore code01
Radial section height (D−d)/26 mm
Smallest bore in 61900-series3 mm
Largest outer diameter in 61900-series1120 mm
Width range across 61900-series3–118 mm
Bore position in 61900-series (smallest first)9 of 63
Bore above smallest 61900-series size9 mm

Cross references & equivalents

Equivalent modelBrandMatch levelNote
61901-2RS-NSK NSK full
Dimensions and internal design equivalent — standard interchange.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901-RSR NSK partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901-ZZ-NSK NSK partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901-NSK NSK partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901-NTN NTN partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901-2RS-NTN NTN full
Dimensions and internal design equivalent — standard interchange.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901-RSR-NTN NTN partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901-ZZ-NTN NTN partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901 SKF partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901-2RS SKF full
Dimensions and internal design equivalent — standard interchange.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
61901-ZZ SKF partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
W61901-2RS SKF partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
W61901-ZZ SKF partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.
W61901 SKF partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 12×24×6 mm envelope per ISO 15; seal variant and load ratings may differ — confirm sealing and rating before substituting.

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 61901-2RS-FAG model number is decoded

In the 61900-series (diameter series 9 of ISO 15) the last two digits encode the bore: 61901 carries bore code 12 = 12 mm. Outside diameter 24 mm and width 6 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 12 mm shaft, typical catalogue practice is a j5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. Schaeffler HR 1 catalogues the lip-contact sealed version as 61901-2RSR (FAG suffix 2RSR), 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

Common applications

  • textile machinery
  • packaging machinery
  • space-constrained gearboxes
  • clutch and transmission assemblies

Known failure patterns

  • seal-lip hardening and loss of pre-grease in sustained high-temperature service
  • grease-life expiry in the sealed-for-life cavity (no relubrication path)
  • edge loading from shaft deflection or housing misalignment
  • rolling-contact fatigue spalling after the rated L10 life is exceeded

Selection pitfalls — read before you substitute

  • Temperature rise and interference fits consume internal clearance on this 12 mm bore: a CN bearing on a tight, hot shaft can lose all residual clearance — size 61901 with C3 for those conditions.
  • The 619xx thin section at 12 mm bore (6.0 mm section height) cannot shrug off the misalignment a standard section tolerates; keep the housing bores round and aligned, or edge contact will spall the raceways early.
  • Contact seals add drag and heat: 61901-2RS-FAG runs slower and cooler-limited than the open 61901; 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 61901-2RS-FAG in solvent or press it home via the outer ring; solvent destroys the grease thickener and mounting force through the seal deforms the lip.
  • Shaft and housing fillets must clear the bearing chamfer so the 6 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
  • Suffixes stack in a defined order — clearance follows the seal code, e.g. 61901-2RS-FAG-C3. No clearance suffix means normal CN clearance.
  • Schaeffler HR 1 lists the lip-contact sealed version as 61901-2RSR (FAG suffix 2RSR), 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. FAG's RSR lip material is NBR as standard — above roughly 100 °C continuous, consult Schaeffler for higher-temperature seal options.
  • FAG rates 61901 at 16700 r/min mechanical limiting speed — electric-motor territory; prefer the open or 2Z execution (sealed 2RSR variants lose roughly a third of the thermal speed) and confirm grease life at the reference speed for continuous running.
  • At 12 mm bore the 61901 sits in Schaeffler's small-bore range; HR 1 ships these sizes with a pressed steel or plastic cage and P0 tolerance as standard — for instrument or spindle accuracy order the P6/P5 variant explicitly, since P0 runout figures will not hold.
  • At 2.89 kN dynamic load rating (C) and 1.46 kN static (C0), 61901 is a light-load FAG bearing: L10 life above a few kN of equivalent load is short, so size up to a 62-series on the same bore if the duty sees shock or frequent starts.
  • At only 12 g, 61901 is a lightweight FAG 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 12×24×6 mm envelope of 61901 gives a D/d ratio of 2.00 and 6.0 mm radial section height — a heavy FAG section 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 2.89/1.46 kN load ratings, mass 12 g here are Schaeffler HR 1 Rolling Bearings (Jan 2020) catalogue figures for 61901-2RSR on the 12×24×6 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61901 in a rated drive. Where FAG has since released an X-life version of this size, its expanded C/C0 ratings supersede the HR 1 print values quoted here.
  • Mixing old and new FAG generations of the same designation in one arrangement is dimensionally acceptable, but where ratings matter — preloaded or matched sets — order both positions from the same generation and lot.
  • FAG standard tolerance for this size is P0 (PN); P6/P5 precision executions exist for spindle-adjacent duty but carry different order numbers in the Schaeffler system — they are not a selectable sorting of standard stock.

Frequently asked questions

What are the dimensions of a 61901-2RS-FAG bearing?

A 61901-2RS-FAG deep-groove ball bearing has a 12 mm bore, 24 mm outer diameter and 6 mm width (0.472 × 0.945 × 0.236 in), per ISO 15 boundary dimensions. It is fitted with two contact rubber seals and is normally pre-greased.

What lubrication does 61901-2RS-FAG need?

61901-2RS-FAG is supplied pre-greased for life and is not designed to be opened for relubrication; where a relubrication path is required, specify the open 61901 with a housing grease fitting instead.

How does the 61901 bore code work?

The last two digits of 61901 are bore code 12, giving 12 × 5 = 12 mm bore. The 24 mm outside diameter and 6 mm width follow the ISO 15 diameter series, not the bore code alone.

What is the FAG suffix for a sealed 61901?

FAG uses suffix 2RSR for the lip-contact rubber seal (catalogue number 61901-2RSR), 2RZ for the non-contact rubber seal and 2Z for steel shields. The industry-neutral spellings on this page (-2RS / -RSR / -ZZ) map to those FAG suffixes while keeping the 12×24×6 mm ISO 15 envelope.

Does FAG offer 61901 with C3 clearance?

FAG lists C3 internal clearance for most deep-groove sizes (suffix C3 follows the seal code); choose C3 for tight fits or hot shafts and stay with the standard CN clearance of 61901-2RSR for normal duty.

Reviewed & verified by the MPN Base engineering desk against source catalog HR 1 Rolling Bearings (Jan 2020) on 2026-09-25. Read our editorial & correction policy.