7311 bearing: complete specifications & equivalents

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 3.1 single-row ACBB) · extracted 2026-09-26

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 3.1 single-row ACBB); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.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 7311 model number is decoded

7311 BEP belongs to SKF's universal single-row angular-contact range — the 55 mm bore entry in the medium (7300) series, dimensioned 120 mm OD and 29 mm wide to the same ISO 15 boundary plan as the 6311 deep-groove envelope.On the SKF nameplate, 7311 follows the ISO numbering convention: 7 for the angular-contact type, 3 for the medium section section, final digits 11 for the 55 mm bore. The suffix decodes as B for the 40° contact-angle execution, E for SKF's enhanced internal design with larger/fewer balls, and P for the glass-fibre reinforced PA66 ball-centred cage (continuous temperature ceiling 120 °C). At 7,000 r/min reference speed the 32.5 mm-section 7311 is governed thermally by preload and lubricant flow; oil-air or grease pack selection should be made against that value, with 6,700 r/min as the mechanical ceiling. A single 7311 locates the shaft in one axial direction only; for bidirectional location order a matched pair — DB for moment stiffness, DF for tolerance of thermal expansion — and size the preload against the real load and speed of the position.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Mount the 55 mm bore 7311 by induction heating of the inner ring (max 120 °C — the PA66 cage sets the ceiling, not the steel); driving it home through the outer ring or balls brinells the asymmetric raceway.
• The 73xx medium section at 55 mm bore (120×29 mm) is heavier-rated than the 7211 but runs hotter at the same speed; do not substitute a 7311 into a 72-series spindle position without re-checking dn, lubricant film and preload.
• When the outer ring rotates, reverse the fit logic and provide outer-ring location; the steep 40° contact of 7311 pushes the rings apart under load, so a non-located outer ring walks its seat even when the shaft is fixed.
• DB (back-to-back) pairs are stiffer against moments, DF (face-to-face) pairs tolerate misalignment and thermal growth better; choosing the arrangement from the 2D drawing rather than the actual shaft thermal expansion is a common 7311 mounting error.
• Catalogue reference speed and limiting speed are different limits: the 7,000 r/min reference is a thermal criterion under load, while the 6,700 r/min limiting value is the mechanical ceiling — observe both.
• The 79.3/55 kN ratings are SKF catalogue 17000 values for the 7311 BEP execution; SKF can revise internal geometry without changing the order number, so keep the catalogue version (PUB BU/P1 17000/1 EN, 2018) with the specification and re-verify for critical drives.
• SKF lists several executions of 7311 (BEP basic, BECBP universally matchable, BE-2RZP sealed, BECBM brass-cage, ACC-series at 25°); they are not interchangeable order numbers — quote the full 7311 BEP designation when purchasing and match the execution to the mounting arrangement.
• A plain 7311 BEP is a single open bearing, not a universally matchable one; to mount a defined DB/DF pair order the BECBP (CB) execution — pairing two unmatched basic units gives uncontrolled preload because the side faces are not ground for set mounting.