51140-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 51140-M model number is decoded

Listed in SKF 17000 chapter 5, 51140 M is an ISO 104 single-direction thrust ball bearing, 200 mm bore and 250 mm OD on a flat housing seat, standing 37 mm high before installation. The bearing is delivered as separate, interchangeable parts: a ground-bore shaft washer, a loose-bore housing washer and the ball-cage assembly between them, designed for one axial load direction only. 51xxx breaks down as 5 for thrust ball, 1 for one load direction on a flat seat, a section digit 1–4 light-to-heavy, then the two-digit bore code. reading the ending 40: bore 200 mm (code 40 × 5) for this single-direction size, via the standard exceptions 00/01/02/03 and ×5 above them. M-cage execution: brass machined from solid and ball-centred, giving heavier guidance than the standard pressed retainer at the top end of the thrust-ball range. Envelope 200×250×37 mm (7.874×9.843×1.457 in), 25.0 mm radial section, C 168 kN, C0 710 kN, Pu 17.6 kN. reference speed 1,400 r/min (thermal) and limiting speed 1,900 r/min (mechanical), catalogue mass 4250 g. Preload at the mechanical ceiling: repeating Fam ≈ A·(n·dm/1000)² with factor A 2.6 at the 1,900 r/min limiting speed raises the required axial preload to about 475.2 kN; the reference-speed value 258.0 kN is the thermal design point. Static-first selection data: 710 kN C0 spread across the 37 mm stack gives 19.2 kN of static rating per height millimetre, and the 4250 g mass/C0 ratio is about 6 g per static kN — crane-hook and screw positions are normally sized on these two figures. Sizing arithmetic on the 200 mm bore: 168 kN C over the 25.0 mm radial section gives 6.7 kN per section millimetre, and the 37 mm stack height is 1.48× that section — proportions typical of a 51100 thrust section. Rating split for documentation: dynamic 168 kN (L10 life), static 710 kN (safety factor s0), fatigue limit 17.6 kN (adjusted life) — three different uses of three different numbers for 51140 M, none interchangeable with another. Selection figures for 51140 M: the C0/C ratio is 4.23, Pu 17.6 kN is about 10 % of C, and the catalogue mass works out to roughly 21 g per millimetre of bore; the printed minimum-load factor is A 2.6. 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 4250 g the machined brass cage represents a meaningful fraction of total mass; balancing checks on high-speed 200 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

• When the housing seat cannot be machined square to the 200 mm shaft, the sphered 53-series execution of this size with its U seat washer is the self-aligning counterpart of this flat 51100 bearing.
• The third digit grades the section: 511 light, then 512, 513 and 514 progressively taller and heavier at the same bore — select from 168/710 kN and the available 250 mm OD, never substitute a lighter series for a heavier one without rechecking C and C0.
• 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 37 mm stack; thrust-ball bearings on horizontal shafts should have the shaft washer (the tight one) against the rotating element.
• 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 51140 against two-way load lifts the loose washer off its raceway.
• Ordering discipline for 51140: the catalogue page quotes 51140 M and its 168/710 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.