7311-BECBP bearing: complete specifications & equivalents

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); 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-BECBP model number is decoded

7311 BECBP is SKF's 55 mm-bore single-row angular-contact ball bearing in the 7300 series, nominal 40° (B) contact angle, 55×120×29 mm to the ISO dimension plan. 40° contact angle (suffix B): the steep standard single-row angle, giving the highest axial capacity at the cost of speed, with a recommended load ratio Fa/Fr ≥ 1. E marks the optimized internal design with an enhanced ball complement and race geometry. glass-fibre reinforced PA66 cage, ball-centred (suffix P), with a 120 °C continuous-temperature ceiling. CB means universally matchable with Normal axial internal clearance: the two side faces are ground so any two units form DB (back-to-back), DF (face-to-face) or DT (tandem) sets without regrinding. Envelope 55×120×29 mm (2.165×4.724×1.142 in), 32.5 mm radial section height, C 85 kN, C0 60 kN, Pu 2.55 kN.reference speed 7,000 r/min (thermal) and limiting speed 7,000 r/min (mechanical), which coincide for this size, catalogue mass 1400 g. Selection figures for 7311 BECBP: the static-to-dynamic ratio C0/C is 0.71, Pu 2.55 kN is about 3 % of C, and catalogue mass works out to roughly 25 g per millimetre of bore. At the printed limiting speed of 7,000 r/min the mean pitch diameter dm ≈ 87.5 mm implies a dn value around 613k mm·r/min; the 7,000 r/min reference speed is the thermal-planning figure under catalogue load. Bore-to-OD planning: OD 120 over bore 55 is a 2.18× step for this size, and the 29 mm width gives a bore/width ratio of 1.90; use these ratios when housing space around the 55 mm shaft is the first constraint. Universal polymer-cage execution: BECBP is the factory-ground set-mounting version of the basic BEP — both side faces are finish-ground to a controlled stand-off so two units form DB, DF or DT arrangements without shims, while the glass-fibre PA66 ball-centred cage keeps the light, quiet running typical of the P-cage range; CB delivers Normal axial clearance before preload is applied at assembly.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• At 55 mm bore the k5 seat assumes a steel shaft and housing; aluminium housings grow faster with temperature, so re-check the outer-ring setting when the case is non-ferrous.
• DB pairs give the highest moment stiffness, DF pairs tolerate misalignment and thermal expansion better, DT shares heavy one-direction thrust; choose from the shaft thermal calculation rather than by habit.
• Fillet radii must clear the chamfer so the 29 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
• One 7311-BECBP locates the shaft in one axial direction only; reversing-thrust positions need a DB or DF pair — or a double-row bearing — with preload set from the load diagram, never from assembly feel.
• The steep 40° angle of 7311-BECBP favours thrust-heavy combined loads; for a predominantly radial high-speed position the 25° ACCBM execution of the same size is the alternative order number.
• Universally matchable BECBP bearings arrive ready for set mounting, not preloaded sets: preload results from how the set is clamped, so follow the SKF stand-off-ring and nut-torque procedure.