51340-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 51340-M model number is decoded

Listed in SKF 17000 chapter 5, 51340 M is an ISO 104 single-direction thrust ball bearing, 200 mm bore and 340 mm OD on a flat housing seat, standing 110 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 200×340×110 mm (7.874×13.386×4.331 in), 70.0 mm radial section, C 624 kN, C0 2600 kN, Pu 58.5 kN. reference speed 630 r/min (thermal) and limiting speed 900 r/min (mechanical), catalogue mass 44500 g. Stack/annulus proportions: the 110 mm axial stack over the 59,376 mm² washer annulus gives 1.85 mm of height per annular square millimetre ×10⁻³, and at 44500 g the bearing holds about 58.4 kN of C0 per kilogram. Envelope economics: the 110 mm axial height over a 70.0 mm radial section yields 5.7 kN of dynamic capacity per height millimetre, and the bearing weighs 44500 g for 624 kN C — about 71 g per rated kN. Pitch-diameter arithmetic: dm = (200+340)/2 = 270.0 mm; at the 900 r/min limiting speed that corresponds to roughly 243k mm·r/min, the figure used when comparing cage speed demand across the thrust-ball series. Speed band width for this size is 270 r/min between reference and limiting (1.43× ratio); lubrication, preload and heat removal decide where inside that band 51340 M can actually run. Speed-ratio note for this exact unit: the reference speed is 630 r/min against a 900 r/min limiting speed, a reference-to-limit ratio of 0.70. 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 44500 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

• The third digit grades the section: 511 light, then 512, 513 and 514 progressively taller and heavier at the same bore — select from 624/2600 kN and the available 340 mm OD, never substitute a lighter series for a heavier one without rechecking C and C0.
• Identify the washers before fitting: the shaft washer has the ground, smaller bore and takes an interference fit on the 200 mm shaft, while the housing washer bore is larger and runs loose; swapping them locks the ball set and burns the tracks.
• 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 51340 against two-way load lifts the loose washer off its raceway.
• 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 51300 bearing.
• Ordering discipline for 51340: the catalogue page quotes 51340 M and its 624/2600 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.