AXK5578 bearing: complete specifications & equivalents
The AXK5578 is a ISO 3031 radial bearing sized 55 x 78 x 3 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 55 mm |
| Outer diameter D | 78 mm |
| Width B | 3 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 34.5 kN |
| Basic static load rating C0 | 186 kN |
| Fatigue load limit Pu | 22.4 kN |
| Reference speed (thermal) | 2200 rpm |
| Limiting speed (mechanical) | 4300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 28 g |
| Manufacturer designation | AXK 5578 |
| Standard | ISO 3031 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 12.1 needle roller and cage thrust assemblies |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 12.1 needle roller and cage thrust assemblies) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 12.1 needle roller and cage thrust assemblies); 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.
Dimensions in inches & AXK-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 3.071 in |
| Width B | 0.118 in |
| ISO bore code | 78 |
| Radial section height (D−d)/2 | 11.5 mm |
| Smallest bore in AXK-series | 4 mm |
| Largest outer diameter in AXK-series | 200 mm |
| Width range across AXK-series | 2–5 mm |
| Bore position in AXK-series (smallest first) | 16 of 30 |
| Bore above smallest AXK-series size | 51 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the AXK5578 model number is decoded
The AXK assembly AXK 5578 covers 55–78 mm in a 3 mm section and is rated 34.5 kN dynamic / 186 kN static: the thinnest rolling thrust support available for that seat. Reading the code: AXK marks the needle thrust assembly and the figures 55/78 give the two raceway diameters in millimetres — 55 mm inner track and 78 mm outer track; TN swaps the stamped steel cage for PA66. The thin section tolerates no misalignment: keep the mating faces parallel, and use the AXW spigot-flanged execution where a one-piece, housing-centred cage-plus-washer unit simplifies assembly. Static safety matters for shock duty: compare peak axial force against C0 186 kN with the application's static factor, since crane hooks and screw positions see their worst load at zero or low speed. Keep the assembly concentric with a shaft shoulder or the housing register — a needle set walking radially off its track is the most common failure; the AXW flanged version removes this risk entirely.
Typical equipment & failure modes
Common applications
- two-wheeler gearbox selector and layshaft thrust faces
- compact drives where hardened washers replace a machined raceway shoulder
- automotive manual and automatic transmission thrust positions
- torque converter and clutch release assemblies in passenger cars
Known failure patterns
- needle-row denting from a single hard particle trapped in the 2 mm section
- roller skidding and raceway glazing once the thrust falls below the catalogue minimum axial load (factor A)
- abrasive paste forming as dust bypasses the housing seals into the open washer set
- brinelling of washer raceways from impact or mounting force applied through the rolling elements
- instant raceway scoring when the assembly runs against a face below 58 HRC or with a rough finish
Selection pitfalls — read before you substitute
- On a 55 mm shaft the cage is only 3 mm thick — a shaft shoulder with a sharp edge or a 0.1 mm burr will catch and spin the cage instead of locating it.
- Match washers by the exact 55–78 mm track — a washer sized to the shaft alone leaves the needles overrunning its edge, which shears the cage.
- the 2,200 r/min reference speed is the thermal criterion under load, the 4,300 r/min limiting speed assumes hardened, ground, oiled faces; soft or dry faces drop the real ceiling drastically.
- The AXK code supplies no washers: AXK 5578 arrives as the needle cage only, and a "bearing failure" on hard-faced tracks is usually a missing-AS-washer failure at ordering time.
- The 34.5 kN rating is real only at 58–64 HRC face hardness; visual inspection cannot tell a 45 HRC washer from a 60 HRC one — order certified washers.
- The 34.5/186 kN ratings and 28 g mass are SKF catalogue values transcribed from ch. 12.1 of PUB BU/P1 17000 (PDF table page 908); mounting data — Ea/Eb raceway diameters and the minimum load factor A — appears in the running text because the structured record carries the boundary envelope only.
Frequently asked questions
Which dimensions does the AXK 5578 have?
A AXK 5578 measures 55 mm bore × 78 mm outside diameter × 3 mm width (2.165 × 3.071 × 0.118 in). From SKF catalogue PUB BU/P1 17000: dynamic C 34.5 kN, static C0 186 kN, fatigue limit Pu 22.4 kN, reference speed 2,200 r/min, limiting speed 4,300 r/min, mass about 28 g. The contact band runs Ea 60–Eb 76 mm; hardened washers or 58–64 HRC faces are required.
What does AXK 55/78 mean?
A needle roller and cage thrust assembly (ISO 3031) for a 55 mm inner track and 78 mm outer track, 3 mm thick; one-direction axial load, washers ordered separately.
What is the difference between AXK and AXW?
AXW pairs the AXK needle set with a washer carrying an integral centring spigot that locates in a housing register, keeping cage and washer concentric as one part; AXK is the bare cage-and-needle set needing two separate washers. The AXW still needs a separate LS/AS washer or hardened face on the opposite side.
Does the AXK 5578 tolerate misalignment?
No — the 3 mm rigid needle set edge-loads on tilted faces. Keep the shaft and housing faces parallel, or choose the self-aligning roller thrust families.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 12.1 needle roller and cage thrust assemblies on 2026-09-27. Read our editorial & correction policy.