53218 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 53218 model number is decoded

53218 is SKF's 90 mm-bore single-direction thrust ball bearing in the 53200 series to the ISO 104 dimension plan, with a sphered housing washer paired to a U seat washer, measuring 90×135×38.5 mm U 218 seat washer companion included in the mounted H1 dimension. 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 53xxx designation the 3 marks a single-direction bearing whose housing washer has a sphered (convex) seating surface, intended to run against the matching U seat washer; the third digit 2–4 grades the section. the final two digits 18 encode the bore as 90 mm (code 18 × 5), the standard SKF bore-code rule shared with radial bearings. with no cage suffix this is the standard execution with a stamped sheet-steel ball-cage assembly (pressed cage) — the light, quiet and economical cage for small and medium thrust-ball sizes. Envelope 90×135×38.5 mm (3.543×5.315×1.516 in), 22.5 mm radial section, C 112 kN, C0 290 kN, Pu 10.4 kN. Mounted height H1 42 mm includes the U 218 seat washer; the bearing alone is 38.5 mm high. reference speed 1,900 r/min (thermal) and limiting speed 2,600 r/min (mechanical), catalogue mass 2100 g. Rating split for documentation: dynamic 112 kN (L10 life), static 290 kN (safety factor s0), fatigue limit 10.4 kN (adjusted life) — three different uses of three different numbers for 53218, none interchangeable with another. Pitch-diameter arithmetic: dm = (90+135)/2 = 112.5 mm; at the 2,600 r/min limiting speed that corresponds to roughly 293k mm·r/min, the figure used when comparing cage speed demand across the thrust-ball series. Speed planning separates the two ceilings mechanically: the pressed cage and balls tolerate 2,600 r/min while thermal balance under catalogue load sets the 1,900 r/min reference; at dm ≈ 112.5 mm the corresponding dn is approximately 293k mm·r/min. Load balance: C0 290 kN against C 112 kN gives a 2.59 ratio — thrust ball bearings are chosen on static rating and F_a/C0 far more often than on L10 life, while Pu 10.4 kN enters the adjusted-life check. Mass and section check: 2100 g inside the 90×135×38.5 mm outline leaves a 22.5 mm radial section, and the 290 kN static rating is 2.59× the dynamic rating — plan static safety and minimum preload against those figures. Sphered-seating order-number note: the convex back face of the housing washer is finish-ground spherical and is delivered to mate with the separately ordered U seat washer, which presents a flat face to the housing and a concave face to the washer; together they accommodate initial static misalignment, but the pair must be kept clean, greased at the spherical interface and never replaced by a washer-on-flat-steel makeshift. Procurement reminder for this specific page: 53218 and U 218 are two order numbers shipping as two articles; the installed 42 mm H1 rather than 38.5 mm H is the dimension the housing drawing must carry.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Dimension the housing to the 42 mm mounted height H1 (bearing plus U 218), not the 38.5 mm bearing height H — confusing the two is a recurring drawing error for the 53-series.
• The sphered housing washer of 53218 MUST run against the U 218 seat washer, a separate order number; mounted bare on a flat register, the convex back makes point contact that gouges the housing under load.
• The self-aligning feature is checked at commissioning by hand: with the shaft under no load the assembly must swivel and settle; a stiff spherical seat means dirt, a mismatched U washer, or a register bored off-axis.
• Replacement orders must list both 53218 and U 218: the seat washer is a separate article, and a U washer of the wrong size narrows the contact band of the 290 kN static-rated set.
• Catalogue ratings are SKF PUB BU/P1 17000 figures for 53218 as the single sphered pressed steel execution; other order numbers of the 53218 size are different products and may carry different ratings or seating geometry — always quote the full designation including the U 218 seat washer when purchasing.