52308 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 52308 model number is decoded

The 52300 series order number 52308 is a SKF double-direction thrust ball bearing for a 30 mm seat, built to ISO 104, with a flat housing seating surface, 30×78×49 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 30×78×49 mm (1.181×3.071×1.929 in), 24.0 mm radial section, C 61.8 kN, C0 122 kN, Pu 4.5 kN. reference speed 2,200 r/min (thermal) and limiting speed 3,000 r/min (mechanical), catalogue mass 1050 g. Envelope economics: the 49 mm axial height over a 24.0 mm radial section yields 1.3 kN of dynamic capacity per height millimetre, and the bearing weighs 1050 g for 61.8 kN C — about 17 g per rated kN. Mass and section check: 1050 g inside the 30×78×49 mm outline leaves a 24.0 mm radial section, and the 122 kN static rating is 1.97× the dynamic rating — plan static safety and minimum preload against those figures. Rating split for documentation: dynamic 61.8 kN (L10 life), static 122 kN (safety factor s0), fatigue limit 4.5 kN (adjusted life) — three different uses of three different numbers for 52308, none interchangeable with another. Light-load floor: Pu = 4.5 kN is the equivalent-load threshold below which the SKF adjusted-life equation credits very long life for 52308; the number is 7 % of the 61.8 kN dynamic rating. Static-first selection data: 122 kN C0 spread across the 49 mm stack gives 2.5 kN of static rating per height millimetre, and the 1050 g mass/C0 ratio is about 9 g per static kN — crane-hook and screw positions are normally sized on these two figures. Double-direction order-number note: the unit is built around one central shaft washer with a ground bore and tracks on both faces, flanked by two housing washers and two independent ball-cage assemblies; observe the assembly orientation (the two housing washers face outwards) and note that a 52-series unit replaces a mirrored pair of 51-series bearings only after the stack height and seat drawings are re-checked. Life accounting for 52308 is done separately per direction: if duty applies 61.8 kN C predominantly one way, the idle side's skid risk — not the loaded side's L10 — usually sets the relubrication and preload interval.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• The double-direction 52308 is one central shaft washer with tracks on both faces, two housing washers and two ball-cage assemblies — a single unit locating the 30 mm shaft axially in both directions instead of a mirrored pair.
• Each direction independently needs the minimum axial load (factor A 0.077): the side that is momentarily unloaded during slow reversal skids first, so arrange preload or symmetry rather than assuming the loaded side drives the idle side.
• Do not replace a 52308 with two single-direction 51-series bearings without re-checking the arrangement: envelope heights, seat details and catalogue ratings differ, even at the same 30×78 mm bore and OD.
• The central shaft washer takes the interference fit on the 30 mm shaft while both outer housing washers run loose in their registers; both loose washers need positive axial retention on vertical shafts.
• Ordering discipline for 52308: the catalogue page quotes 52308 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.