618-900-MA bearing: complete specifications & equivalents
The 618-900-MA is a ISO 15 radial bearing sized 900 x 1090 x 85 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 900 mm |
| Outer diameter D | 1090 mm |
| Width B | 85 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 618 kN |
| Basic static load rating C0 | 1600 kN |
| Fatigue load limit Pu | 21.6 kN |
| Reference speed (thermal) | 850 rpm |
| Limiting speed (mechanical) | 700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 167000 g |
| Manufacturer designation | 618/900 MA |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
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.
Dimensions in inches & 61800-series range
| Bore d | 35.433 in |
|---|---|
| Outer diameter D | 42.913 in |
| Width B | 3.346 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 95 mm |
| Smallest bore in 61800-series | 1 mm |
| Largest outer diameter in 61800-series | 1820 mm |
| Width range across 61800-series | 1–140 mm |
| Bore position in 61800-series (smallest first) | 67 of 74 |
| Bore above smallest 61800-series size | 899 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 618-900-MA model number is decoded
In the large-bore 61800-series, the bore is written directly after the slash as 900 mm (large thin-section bores use the slash spelling instead of the two-digit code). The envelope is 900×1090×85 mm (35.433×42.913×3.346 in) with a 95.0 mm radial section height, C 618 kN, C0 1600 kN and Pu 21.6 kN. The open 618/900 MA carries no shields or seals and relies on application lubrication and external sealing. The MA suffix identifies the machined brass cage execution, a separate order number from the pressed-steel version. Limiting speed 700 r/min, catalogue mass 167000 g. A thin section saves space but leaves little margin for misalignment or shaft deflection.
Typical equipment & failure modes
Common applications
- marine deck machinery
- crusher auxiliary drives
- space-constrained gearboxes
- clutch and transmission assemblies
Known failure patterns
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
- brinelling from static overload or hammer blows during mounting
- false brinelling from vibration while the shaft stands idle
Selection pitfalls — read before you substitute
- Do not preload 618-900-MA to silence it: a deep-groove ball bearing is not angular-contact, and axial preload only raises temperature and shortens grease life.
- Mount by heating the inner ring (max 120 °C) — driving 618-900-MA home through the outer ring or balls brinells the raceways.
- The MA suffix on 618-900-MA denotes a machined brass cage: it is the choice for high speeds, marginal lubrication and shock/vibration duty, and it is temperature-tolerant where polymer cages are not — the 167000 g quoted mass includes the heavier cage.
- Open 618-900-MA needs external sealing at the arrangement level; in dusty housings its life depends entirely on those external seals and the regreasing schedule.
- Plan a relubrication interval for 618-900-MA; run-to-failure on open deep-groove bearings is the dominant early-failure cause.
- At 900 mm bore, C3 clearance is the safe choice when interference fits plus temperature rise consume the CN clearance; a hot tight bearing with no residual clearance fails fast.
Frequently asked questions
What are the dimensions of 618-900-MA?
The SKF 618/900 MA measures 900 mm bore × 1090 mm OD × 85 mm width (35.433 × 42.913 × 3.346 in), mass about 167000 g. It is open, with no shields or seals.
Why is there a slash in the designation 618/900 MA?
The slash writes a bore that falls outside the two-digit code table: 618/900 means 900 mm bore. The site slug 618-900-MA replaces the slash with a hyphen.
What load can 618-900-MA take?
Catalogue values for 618/900 MA: dynamic C 618 kN, static C0 1600 kN, fatigue limit Pu 21.6 kN. Use C in life calculation and C0 for static checks at 900 mm bore.
What is the speed rating of 618-900-MA?
SKF lists a 850 r/min thermal reference speed and a 700 r/min mechanical limiting speed for 618/900 MA; real limits also depend on lubrication and fits.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.