51244-M 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 51244-M model number is decoded

51244 M is SKF's 220 mm-bore single-direction thrust ball bearing in the 51200 series to the ISO 104 dimension plan, with a flat housing seating surface, measuring 220×300×63 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 44 encode the bore as 220 mm (code 44 × 5), the standard SKF bore-code rule shared with radial bearings. suffix M identifies a one-piece machined brass cage, ball-centred: the large-size and heavy-section option for higher speeds, shock loads and thin-film lubrication where a pressed cage would distort. Envelope 220×300×63 mm (8.661×11.811×2.48 in), 40.0 mm radial section, C 358 kN, C0 1460 kN, Pu 33.5 kN. reference speed 950 r/min (thermal) and limiting speed 1,300 r/min (mechanical), catalogue mass 13000 g. Load balance: C0 1460 kN against C 358 kN gives a 4.08 ratio — thrust ball bearings are chosen on static rating and F_a/C0 far more often than on L10 life, while Pu 33.5 kN enters the adjusted-life check. Speed band width for this size is 350 r/min between reference and limiting (1.37× ratio); lubrication, preload and heat removal decide where inside that band 51244 M can actually run. Track-circle loading: per millimetre of mean track circumference the 358 kN dynamic rating corresponds to roughly 0.44 kN/mm of π·dm track, a useful comparison against the other dimension series of the 220 mm bore. Stack/annulus proportions: the 63 mm axial stack over the 32,673 mm² washer annulus gives 1.93 mm of height per annular square millimetre ×10⁻³, and at 13000 g the bearing holds about 112.3 kN of C0 per kilogram. Mass and section check: 13000 g inside the 220×300×63 mm outline leaves a 40.0 mm radial section, and the 1460 kN static rating is 4.08× the dynamic rating — plan static safety and minimum preload against those figures. Machined-cage order-number note: the M brass cage is a one-piece ball-centred window cage, chosen at the heavy end of the section for speed and shock duty; it is heavier and stiffer than the pressed-steel execution of the smaller sizes and tolerates interrupted lubrication far better, which is why the catalogue restricts the M suffix to the large bores. The M cage of 51244 M adds a small amount of mass and cage strength without changing the 220×300×63 mm ISO 104 envelope, so the pressed-cage execution drops into the same recess but should not be assumed equal under the 1,300 r/min ceiling.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Identify the washers before fitting: the shaft washer has the ground, smaller bore and takes an interference fit on the 220 mm shaft, while the housing washer bore is larger and runs loose; swapping them locks the ball set and burns the tracks.
• 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 358 kN track before first rotation.
• When the housing seat cannot be machined square to the 220 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.
• 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 63 mm stack; thrust-ball bearings on horizontal shafts should have the shaft washer (the tight one) against the rotating element.
• The 358/1460 kN figures belong to 51244 M specifically (the single flat brass execution of 51244); suffixed, sphered and counterpart-series order numbers are separate articles, so write the complete designation on the order and the maintenance record.