51201-SKF bearing: complete specifications & equivalents

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-28

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 51201-SKF model number is decoded

51201 is SKF's 12 mm-bore single-direction thrust ball bearing in the 51200 series to the ISO 104 dimension plan, with a flat housing seating surface, measuring 12×28×11 mm. The separable set comprises a shaft washer (ground bore, tight fit on the shaft), a loose-bore housing washer and one ball-cage assembly, reacting axial force in one direction and carrying no radial load. in the 51xxx designation the first 1 marks a single-direction bearing with a flat housing seating surface; the third digit 1–4 grades the dimension series from the light 511 section through the heavy 514 section. the final two digits 01 encode the bore as 12 mm, the standard SKF bore-code rule shared with radial bearings. with no cage suffix this is the standard execution with a stamped sheet-steel ball-cage assembly (pressed cage) — the light, quiet and economical cage for small and medium thrust-ball sizes. Envelope 12×28×11 mm (0.472×1.102×0.433 in), 8.0 mm radial section, C 13.3 kN, C0 20.8 kN, Pu 0.765 kN. reference speed 8,000 r/min (thermal) and limiting speed 11,000 r/min (mechanical), catalogue mass 34 g. Minimum-load arithmetic: with dm ≈ 20.0 mm and factor A 0.0022, Fam ≈ A·(n·dm/1000)² at the 8,000 r/min reference speed is about 56 N for 51201; below that preload the balls skid and smear the tracks. Bore-to-OD planning: OD 28 over bore 12 is a 2.33× step for this size, and the 11 mm height gives a bore/height ratio of 1.09; use these ratios when the housing recess around the 12 mm shaft is the first constraint. Pitch-diameter arithmetic: dm = (12+28)/2 = 20.0 mm; at the 11,000 r/min limiting speed that corresponds to roughly 220k mm·r/min, the figure used when comparing cage speed demand across the thrust-ball series. Rating split for documentation: dynamic 13.3 kN (L10 life), static 20.8 kN (safety factor s0), fatigue limit 0.765 kN (adjusted life) — three different uses of three different numbers for 51201, none interchangeable with another. Envelope economics: the 11 mm axial height over a 8.0 mm radial section yields 1.2 kN of dynamic capacity per height millimetre, and the bearing weighs 34 g for 13.3 kN C — about 3 g per rated kN. Execution note for this order number: the flat housing seating surface must be machined square to the shaft axis and supported across the full washer face — unlike the sphered 53-series execution this pressed-cage 51-series bearing has no self-aligning capability at all, so seat squareness is checked at mounting, not compensated in service. Inspection after removal of a 11 mm-high stack means checking both washer faces: the loose housing washer often shows the first false-brinell marks under machine vibration even though the tight shaft washer carries the rotating load of 13.3 kN C.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• A 51-series bearing reacts thrust in one direction only — reversing positions need a mirrored single-direction pair or a 52-series double-direction unit; fitting a single 51201 against two-way load lifts the loose washer off its raceway.
• When the housing seat cannot be machined square to the 12 mm shaft, the sphered 53-series execution of this size with its U seat washer is the self-aligning counterpart of this flat 51200 bearing.
• The three components are separable and interchangeable within the ISO 104 size, but keep this bearing's parts together in service and never combine washers from different manufacturers or a worn washer with a new ball set.
• Identify the washers before fitting: the shaft washer has the ground, smaller bore and takes an interference fit on the 12 mm shaft, while the housing washer bore is larger and runs loose; swapping them locks the ball set and burns the tracks.
• Catalogue ratings are SKF PUB BU/P1 17000 figures for 51201 as the single flat pressed steel execution; other order numbers of the 51201 size are different products and may carry different ratings or seating geometry — always quote the full designation when purchasing.