7311-BECBY 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-BECBY model number is decoded

7311 BECBY 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. stamped brass cage, ball-centred (suffix Y) — lighter than the machined M cage but brass rather than polymer. 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. BECBY combines the optimized 40° geometry with CB universal clearance and a stamped brass Y cage. Envelope 55×120×29 mm (2.165×4.724×1.142 in), 32.5 mm radial section height, C 90 kN, C0 65.5 kN, Pu 2.75 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 BECBY: the static-to-dynamic ratio C0/C is 0.73, Pu 2.75 kN is about 3 % of C, and catalogue mass works out to roughly 25 g per millimetre of bore. Load balance: C0 65.5 kN against C 90 kN gives a 0.73 ratio, typical of a steep-angle axial-oriented design; Pu 2.75 kN enters the SKF adjusted-life equation rather than the basic rating life. 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. Cage detail specific to this order number: the Y cage is stamped from brass strip into ball pockets rather than machined from solid, giving a lighter cage assembly and lower centrifugal mass than the M execution; it remains brass (temperature and oil-additive tolerant, unlike PA66) but is the formed-cage design, and the machined-brass BECBM order number remains the choice for severe shock or marginal lubrication.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• 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.
• Preload the set against a calculated stand-off dimension — the ground faces of BECBY establish it, but locknut torque, sleeve crush and housing-face squareness each consume part of the allowance.
• Greased positions should fill roughly 25–35 % of the free volume on a 7311-BECBY of this section and route the surplus past the outer ring; overpacking churns the grease and reproduces the thermal preload problem mechanically.
• 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.
• The steep 40° angle of 7311-BECBY 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 BECBY 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.