61948-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 61948-FAG model number is decoded

In the 61900-series (diameter series 9 of ISO 15) the last two digits encode the bore: 61948 carries bore code 48 = 240 mm. Outside diameter 320 mm and width 38 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 240 mm shaft, typical catalogue practice is a m6 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. 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 240 mm bore the ring mass is significant: heat 61948 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 619xx thin section (40.0 mm section height at 240 mm bore) trades load capacity for compactness; stiff, accurately aligned seats are essential or edge loading will spall the raceway early.
• The open 61948-FAG has no lubricant retention: grease escapes and contaminants migrate straight into the 240×320×38 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
• Open bearings tolerate the highest speeds in the 61900-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 61948 units.
• The housing bore for the 320 mm OD should be round within IT7; an oval bore pinches the outer ring of 61948-FAG and shows up later as two-point loaded raceway wear.
• Axial location must clamp the ring face, not the seal area: a shoulder or circlip bearing on the seal side of the 38 mm-wide ring of 61948-FAG drags the lip and overheats it.
• The open 61948 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 2600 r/min for 61948 (thermal reference speed 2330 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 240 mm bore places 61948 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.
• FAG rates 61948 at 211 kN dynamic (C) and 240 kN static (C0); this is an extreme-load rating at the top of the HR 1 single-row deep-groove range, where mounting, shaft stiffness and housing alignment dominate achievable life — request a Schaeffler application review rather than relying on catalogue L10 alone.
• At 6780 g (6.8 kg), 61948 is a heavy FAG bearing that requires a crane or hoist for handling; induction-heat the inner ring (max 120 °C) and use a mechanical puller for removal — never apply heat directly to the balls or cage.
• The 240×320×38 mm envelope of 61948 gives a D/d ratio of 1.33 and only 40.0 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 211/240 kN load ratings, mass 6780 g here are Schaeffler HR 1 Rolling Bearings (Jan 2020) catalogue figures for 61948-FAG on the 240×320×38 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 61948 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.
• FAG sealed units arrive greased for life with a lithium-soap fill; Schaeffler quotes a shelf life for greased bearings and recommends running stock first-in-first-out rather than re-greasing aged sealed units.
• 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.