54308 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 54308 model number is decoded

The 54300 series order number 54308 is a SKF double-direction thrust ball bearing for a 30 mm seat, built to ISO 104, with a sphered housing washer paired to a U seat washer, 30×78×54.1 mm boundary dimensions. Inside the unit sit a single central shaft washer with a ground interference bore, two outward-facing loose housing washers and two independent ball-cage assemblies, so axial force is reacted in both directions from one housing recess. bore-coding caveat: on 52/54 double-direction bearings the last two digits are an order-number code, not ×5 millimetres — this size carries a 30 mm bore per the ISO 104 table, and guessing from the code gives the wrong shaft. the suffix-free listing carries the catalogue default: a pressed (stamped sheet-steel) ball-cage assembly, light and quiet, used across the small and medium sizes. Envelope 30×78×54.1 mm (1.181×3.071×2.13 in), 24.0 mm radial section, C 61.8 kN, C0 122 kN, Pu 4.5 kN. Mounted height H1 59 mm includes the U 308 seat washer; the bearing alone is 54.1 mm high. reference speed 2,200 r/min (thermal) and limiting speed 3,000 r/min (mechanical), catalogue mass 1150 g. Speed band width for this size is 800 r/min between reference and limiting (1.36× ratio); lubrication, preload and heat removal decide where inside that band 54308 can actually run. Capacity density: 61.8 kN C from 1.150 kg of bearing steel gives about 53.7 kN per kilogram; static density is correspondingly 106.1 kN/kg at C0 122 kN. At the printed limiting speed of 3,000 r/min the mean pitch diameter dm ≈ 54.0 mm implies a dn value around 162k mm·r/min; the 2,200 r/min reference speed is the thermal-planning value under catalogue load. Preload at the mechanical ceiling: repeating Fam ≈ A·(n·dm/1000)² with factor A 0.077 at the 3,000 r/min limiting speed raises the required axial preload to about 2.0 kN; the reference-speed value 1.1 kN is the thermal design point. Minimum-load arithmetic: with dm ≈ 54.0 mm and factor A 0.077, Fam ≈ A·(n·dm/1000)² at the 2,200 r/min reference speed is about 1.1 kN for 54308; below that preload the balls skid and smear the tracks. Bidirectional self-aligning note: TWO U seat washers are required for this order number, one behind each housing washer, and the catalogue H1 height includes them on both sides of the stack; the spherical interfaces accept initial misalignment in either load direction but are not pivots for continuous oscillation. Bill of materials for this page is 54308 plus TWO × U 308; the 59 mm H1 stack sits in a housing whose two register faces should be machined in one clamping to keep both spherical axes coincident.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• The 61.8/122 kN ratings assume the spherical contacts are free to find their seat — a painted-over or shimmed U washer fixes the angle and turns the self-aligning bearing into an edge-loaded one.
• Replacement ordering is THREE numbers: 54308 plus two pieces of U 308; quoting only the bearing leaves the sphered backs running on bare registers.
• Assembly is a five-component stack (central shaft washer, two cage sets, two sphered housing washers) plus the two U seat washers in the housing registers; dry-build the arrangement by hand first to confirm both sides swivel freely.
• Order TWO seat washers for 54308 — the designation U 308 pairs with one side and a second U washer (same number) with the other; the catalogue 59 mm H1 includes both.
• Ordering discipline for 54308: the catalogue page quotes 54308 plus U 308 and its 61.8/122 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.