61844-FAG bearing: complete specifications & equivalents

Specification table

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.

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 61844-FAG model number is decoded

61844 is supplied open, without shields or seals, so the arrangement around it must supply and retain the lubricant. Within the extra-thin 618xx section (diameter series 8 of ISO 15), multiplying bore code 44 by five gives the 220 mm bore; the 270 mm outside diameter and 24 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 220 mm shaft under normal load, catalogue practice seats it on a m6 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. In the Schaeffler HR 1 catalogue this open execution carries the bare designation; protected variants are ordered separately with suffixes 2Z (steel shields), 2RZ (non-contact rubber seals) and 2RSR (lip-contact rubber seals).

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• At 220 mm bore the ring mass is significant: heat 61844 on an induction heater (max 120 °C), never over an open flame, and plan puller access or a withdrawal sleeve now for the day it has to come off again.
• The 618xx thin section at 220 mm bore has only a 25.0 mm radial section height: it saves space but is highly sensitive to misalignment, shaft deflection and shock loads — verify shaft stiffness before choosing it over a 6244.
• Storage matters for open bearings: 61844-FAG leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
• Open bearings tolerate the highest speeds in the 61800-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61844 units.
• Grease compatibility is not guaranteed between fills: mixing lithium and polyurea thickeners in a 61800-series position can soften the mixture and leak — clean out the old fill before switching grease types.
• Deep-groove ball bearings tolerate only minutes of misalignment; if the 270 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 61844-FAG.
• The open 61844 has no integral sealing; in the Schaeffler HR 1 catalogue the protected variants carry suffixes 2Z (two steel shields), 2RZ (two non-contact rubber seals) and 2RSR (two lip-contact rubber seals). Do not confuse FAG's 2RZ with a contact seal — the RZ lip does not touch the inner ring, which is why its speed capability stays close to the open bearing.
• FAG lists the mechanical limiting speed at 3200 r/min for 61844 (thermal reference speed 2320 r/min); the thermal reference speed is the binding figure for continuous duty — size the lubrication interval off the reference speed, not the mechanical limit.
• The 220 mm bore places 61844 at the upper end of the HR 1 single-row deep-groove extract; this is a heavy-engineering size where centrifugal force, mounting heat and housing alignment dominate. FAG supplies a machined brass cage (suffix M) and expects oil lubrication with a defined relubrication interval — do not use grease speed figures for this size without a Schaeffler engineering review.
• At 78 kN dynamic load rating (C) and 97 kN static (C0), 61844 is a heavy-load FAG bearing for industrial gearboxes and large conveyors; Schaeffler expects a machined brass cage (suffix M) at this rating for shock duty, and C0 must be checked against mounting or lifting loads.
• At 2500 g (2.5 kg), 61844 needs mechanical handling for mounting; Schaeffler recommends induction heating the inner ring (max 120 °C) rather than pressing cold, and a lifting provision if the housing is pre-assembled.
• The 220×270×24 mm envelope of 61844 gives a D/d ratio of 1.23 and only 25.0 mm radial section height — an ultra-thin section in the HR 1 range where shaft deflection and housing ovality load the ball-raceway contact directly; verify shaft stiffness (target deflection under 0.05 mm) before choosing it over a 62-series.
• The 78/97 kN load ratings, mass 2500 g here are Schaeffler HR 1 Rolling Bearings (Jan 2020) catalogue figures for 61844-FAG on the 220×270×24 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61844 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.
• Schaeffler's medias/eKatalog is the live source for the current execution of 61844: cage material, seal lip design and ratings can be revised between catalogue generations without any designation change.