7256-BM 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 7256-BM model number is decoded

7256 BM is SKF's 280 mm-bore single-row angular-contact ball bearing in the 7200 series, nominal 40° (B) contact angle, 280×500×80 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. machined brass cage, ball-centred (suffix M), the choice for high speed, marginal lubrication and shock duty. The BM is the non-optimized basic 40° execution with a machined brass cage; it predates the E geometry and is stocked for positions built around its specific figures.. Envelope 280×500×80 mm (11.024×19.685×3.15 in), 110.0 mm radial section height, C 507 kN, C0 830 kN, Pu 17.6 kN.reference speed 1,400 r/min (thermal) and limiting speed 1,400 r/min (mechanical), which coincide for this size, catalogue mass 67500 g. Mass and section check: 67500 g inside the 280×500×80 mm outline leaves a 110.0 mm radial section, and the 830 kN static rating is 1.64× the dynamic rating — plan static safety and minimum load against those numbers rather than against sister executions. Load balance: C0 830 kN against C 507 kN gives a 1.64 ratio, typical of a steep-angle axial-oriented design; Pu 17.6 kN enters the SKF adjusted-life equation rather than the basic rating life. Speed-ratio note for this exact unit: the reference speed is 1,400 r/min against a 1,400 r/min limiting speed, i.e. a reference-to-limit ratio of 1.00. Non-optimized basic execution: BM is the earlier 40-degree design without the E internal upgrade, fitted with a machined brass ball-centred cage as a single (non-universal) bearing; quote it for housings and spacers designed around the legacy geometry.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Fillet radii must clear the chamfer so the 80 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
• At 280 mm bore the m6 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.
• At 280 mm bore the m6 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.
• Do not mix execution classes inside one set: a universally matchable BM unit is ground for arbitrary pairing, a basic execution is not.
• The steep 40° angle of 7256-BM 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.
• Catalogue ratings are SKF PUB BU/P1 17000 figures for 7256 BM as the single non e brass execution; the other order numbers of the 7256 size are different products and may carry different ratings — always quote the full designation when purchasing.