51228 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 51228 model number is decoded

Listed in SKF 17000 chapter 5, 51228 is an ISO 104 single-direction thrust ball bearing, 140 mm bore and 200 mm OD on a flat housing seat, standing 46 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 28: bore 140 mm (code 28 × 5) for this single-direction size, via the standard exceptions 00/01/02/03 and ×5 above them. no cage suffix means the standard stamped steel retainer — a pressed sheet-metal ball-cage assembly that covers the bulk of the thrust-ball assortment. Envelope 140×200×46 mm (5.512×7.874×1.811 in), 30.0 mm radial section, C 190 kN, C0 620 kN, Pu 17.6 kN. reference speed 1,400 r/min (thermal) and limiting speed 1,900 r/min (mechanical), catalogue mass 4350 g. Imperial cross-check for procurement drawings: 5.512 in bore, 7.874 in OD, 1.811 in height, and the 4350 g catalogue mass converts to 4.350 kg (153.4 oz). Speed planning separates the two ceilings mechanically: the pressed cage and balls tolerate 1,900 r/min while thermal balance under catalogue load sets the 1,400 r/min reference; at dm ≈ 170.0 mm the corresponding dn is approximately 323k mm·r/min. At the printed limiting speed of 1,900 r/min the mean pitch diameter dm ≈ 170.0 mm implies a dn value around 323k mm·r/min; the 1,400 r/min reference speed is the thermal-planning value under catalogue load. Stack/annulus proportions: the 46 mm axial stack over the 16,022 mm² washer annulus gives 2.87 mm of height per annular square millimetre ×10⁻³, and at 4350 g the bearing holds about 142.5 kN of C0 per kilogram. Track-circle loading: per millimetre of mean track circumference the 190 kN dynamic rating corresponds to roughly 0.36 kN/mm of π·dm track, a useful comparison against the other dimension series of the 140 mm bore. 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 140 mm size the pressed cage and separable washers make the bearing interchangeable across brands on the ISO 104 plan, but the SKF ratings 190/620 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

• When the housing seat cannot be machined square to the 140 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.
• The 51228 is a pure axial bearing: it must never be subjected to radial load — any radial force on the 140 mm shaft has to be carried by a radial bearing mounted alongside it.
• 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 51228 against two-way load lifts the loose washer off its raceway.
• 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 190 kN track before first rotation.
• Ordering discipline for 51228: the catalogue page quotes 51228 and its 190/620 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.