7308-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 7308-BECBY model number is decoded

7308 BECBY is SKF's 40 mm-bore single-row angular-contact ball bearing in the 7300 series, nominal 40° (B) contact angle, 40×90×23 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 40×90×23 mm (1.575×3.543×0.906 in), 25.0 mm radial section height, C 53 kN, C0 35.5 kN, Pu 1.5 kN.reference speed 9,500 r/min (thermal) and limiting speed 10,000 r/min (mechanical), catalogue mass 640 g. At the printed limiting speed of 10,000 r/min the mean pitch diameter dm ≈ 65.0 mm implies a dn value around 650k mm·r/min; the 9,500 r/min reference speed is the thermal-planning figure under catalogue load. The 1.5 kN fatigue load limit is the equivalent-load floor for long-life adjustment; with 53/35.5 kN ratings and 640 g mass this execution carries about 1.32 kN of C per millimetre of bore. Bore-to-OD planning: OD 90 over bore 40 is a 2.25× step for this size, and the 23 mm width gives a bore/width ratio of 1.74; use these ratios when housing space around the 40 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

• Mount by induction-heating the inner ring to max 120 °C; driving the bearing home through the outer ring or balls brinells the asymmetric raceway.
• Assign interference to the rotating ring — roughly k5 on a 40 mm rotating shaft with an H7 housing — and let the stationary ring slide for axial setting; reverse the logic if the outer ring rotates.
• Do not mix execution classes inside one set: a universally matchable BECBY unit is ground for arbitrary pairing, a basic execution is not.
• Reference and limiting speeds are different ceilings: design to both, and remember preload and oil/air cooling move the real thermal limit far from the catalogue reference value.
• The steep 40° angle of 7308-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.