51101-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 51101-SKF model number is decoded

51101 is SKF's 12 mm-bore single-direction thrust ball bearing in the 51100 series to the ISO 104 dimension plan, with a flat housing seating surface, measuring 12×26×9 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 12×26×9 mm (0.472×1.024×0.354 in), 7.0 mm radial section, C 10.4 kN, C0 16.6 kN, Pu 0.62 kN. reference speed 9,000 r/min (thermal) and limiting speed 13,000 r/min (mechanical), catalogue mass 22 g. Mass and section check: 22 g inside the 12×26×9 mm outline leaves a 7.0 mm radial section, and the 16.6 kN static rating is 1.60× the dynamic rating — plan static safety and minimum preload against those figures. Stack/annulus proportions: the 9 mm axial stack over the 418 mm² washer annulus gives 21.53 mm of height per annular square millimetre ×10⁻³, and at 22 g the bearing holds about 754.5 kN of C0 per kilogram. Speed planning separates the two ceilings mechanically: the pressed cage and balls tolerate 13,000 r/min while thermal balance under catalogue load sets the 9,000 r/min reference; at dm ≈ 19.0 mm the corresponding dn is approximately 247k mm·r/min. Speed band width for this size is 4,000 r/min between reference and limiting (1.44× ratio); lubrication, preload and heat removal decide where inside that band 51101 can actually run. Light-load floor: Pu = 0.62 kN is the equivalent-load threshold below which the SKF adjusted-life equation credits very long life for 51101; the number is 6 % of the 10.4 kN dynamic rating. 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. On this 12 mm size the pressed cage and separable washers make the bearing interchangeable across brands on the ISO 104 plan, but the SKF ratings 10.4/16.6 kN are this catalogue's figures — confirm the replacement order's ratings rather than swapping on envelope alone.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Keep the applied thrust above Fam ≈ A·(n·dm/1000)² with the printed factor A 0.0014; for 51101 a spring preload or the rotor weight is part of the selection at light load and high speed, because unloaded balls skid rather than roll.
• On vertical shafts retain the loose housing washer positively with a cover or ring and verify the grease fill does not drain out of the 9 mm stack; thrust-ball bearings on horizontal shafts should have the shaft washer (the tight one) against the rotating element.
• 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.
• Heat the shaft washer to at most 120 °C for mounting, or press it via a sleeve on its ground bore — force applied through the housing washer or the ball set brinells the 10.4 kN track before first rotation.
• Ordering discipline for 51101: the catalogue page quotes 51101 and its 10.4/16.6 kN ratings as one exact article; bare-number substitutions from another series or brand need a fresh dimension and rating check, not a like-for-like assumption.