51232-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 51232-M model number is decoded

The 51200 series order number 51232 M is a SKF single-direction thrust ball bearing for a 160 mm seat, built to ISO 104, with a flat housing seating surface, 160×225×51 mm boundary dimensions. Three separable parts make the set: the tight-bore shaft washer that locates on the shaft, the loose-bore housing washer in its register, and the ball-cage assembly; load is purely axial and acts in one direction. reading 51xxx as a code: the 1 after 5 identifies one load direction and a flat seat, and the next digit ranks the section 1 (light) to 4 (heavy) before the two-digit bore code. bore code 32 decodes to 160 mm (code 32 × 5) under the same 00/01/02/03-exception, ×5 rule SKF uses across its coded bearing ranges. the trailing M names a solid machined brass window cage centred on the balls rather than on a washer, the catalogue choice when size, speed or interrupted lubrication rules out sheet steel. Envelope 160×225×51 mm (6.299×8.858×2.008 in), 32.5 mm radial section, C 238 kN, C0 830 kN, Pu 22.4 kN. reference speed 1,200 r/min (thermal) and limiting speed 1,700 r/min (mechanical), catalogue mass 6550 g. Capacity density: 238 kN C from 6.550 kg of bearing steel gives about 36.3 kN per kilogram; static density is correspondingly 126.7 kN/kg at C0 830 kN. Selection figures for 51232 M: the C0/C ratio is 3.49, Pu 22.4 kN is about 9 % of C, and the catalogue mass works out to roughly 41 g per millimetre of bore; the printed minimum-load factor is A 3.8. Minimum-load arithmetic: with dm ≈ 192.5 mm and factor A 3.8, Fam ≈ A·(n·dm/1000)² at the 1,200 r/min reference speed is about 202.8 kN for 51232 M; below that preload the balls skid and smear the tracks. Pitch-diameter arithmetic: dm = (160+225)/2 = 192.5 mm; at the 1,700 r/min limiting speed that corresponds to roughly 327k mm·r/min, the figure used when comparing cage speed demand across the thrust-ball series. Speed-ratio note for this exact unit: the reference speed is 1,200 r/min against a 1,700 r/min limiting speed, a reference-to-limit ratio of 0.71. 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. At 6550 g the machined brass cage represents a meaningful fraction of total mass; balancing checks on high-speed 160 mm vertical shafts should use the actual M-execution weight, not the lighter pressed-cage catalogue value.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• 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 51 mm stack; thrust-ball bearings on horizontal shafts should have the shaft washer (the tight one) against the rotating element.
• Keep the applied thrust above Fam ≈ A·(n·dm/1000)² with the printed factor A 3.8; for 51232 M 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.
• When the housing seat cannot be machined square to the 160 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.
• 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 238 kN track before first rotation.
• Catalogue ratings are SKF PUB BU/P1 17000 figures for 51232 M as the single flat brass execution; other order numbers of the 51232 size are different products and may carry different ratings or seating geometry — always quote the full designation when purchasing.