6311-2RS-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 6311-2RS-FAG model number is decoded

6311-2RS is closed by two contacting elastomer lips over a lifetime grease fill; the lips add friction, so the speed ceiling sits below the open execution. Within the medium 63xx section (diameter series 3 of ISO 15), multiplying bore code 11 by five gives the 55 mm bore; the 120 mm outside diameter and 29 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 55 mm shaft under normal load, catalogue practice seats it on a k5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. Schaeffler HR 1 catalogues the lip-contact sealed version as 6311-C-2HRS (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

Selection pitfalls — read before you substitute

• Interference on a 55 mm shaft plus running heat consumes radial clearance: where the shaft runs hot or the fit is tight, order 6311 with C3 clearance and re-check the residual value after mounting.
• The 63xx medium section at 55 mm bore gains dynamic rating through larger rolling elements on a 120 mm OD; the penalty is mass and a lower limiting speed than the 6211 — do not specify it for speed-critical shafts.
• Contact seals add drag and heat: 6311-2RS-FAG runs slower and cooler-limited than the open 6311; 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 6311-2RS-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.
• Deep-groove ball bearings tolerate only minutes of misalignment; if the 120 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 6311-2RS-FAG.
• A 55 mm bore listing showing the right d/D/B but no standard or precision-class reference may be a loose-tolerance import; measure bore/OD spread before fitting it to a machined shaft.
• Schaeffler HR 1 lists the lip-contact sealed version as 6311-C-2HRS (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.
• At 5300 r/min mechanical limiting speed, 6311 covers medium-duty industrial drives; the 2RSR lip-contact seal is the practical speed limiter — for continuous operation near the ceiling use the open or 2RZ variant with external housing sealing.
• At 55 mm bore 6311 is in Schaeffler's upper general-purpose range; the pressed steel cage is standard but mid-section 63xx sizes at this bore can be ordered with a machined brass cage (suffix M) for shock or very-low-speed duty — confirm cage material with the Schaeffler channel if the application sees impact loads.
• At 83 kN dynamic load rating (C) and 47.5 kN static (C0), 6311 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 1370 g (1.4 kg), 6311 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 55×120×29 mm envelope of 6311 gives a D/d ratio of 2.18 and 32.5 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 83/47.5 kN load ratings, mass 1370 g here are Schaeffler HR 1 Rolling Bearings (Jan 2020) catalogue figures for 6311-C-2HRS on the 55×120×29 mm ISO 15 envelope; internal geometry and ratings legitimately differ between brands, so re-verify before substituting another manufacturer's 6311 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.
• For hot shafts above roughly 100 °C continuous, consult Schaeffler about seal material and grease options for the 2RSR execution of 6311; the standard NBR lip is the economical general-duty choice, not the high-temperature one.
• Schaeffler's medias/eKatalog is the live source for the current execution of 6311: cage material, seal lip design and ratings can be revised between catalogue generations without any designation change.