6318-2RS bearing: complete specifications & equivalents
The 6318-2RS is a ISO 15 radial bearing sized 90 x 190 x 43 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Bore diameter d | 90 mm |
| Outer diameter D | 190 mm |
| Width B | 43 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 151 kN |
| Basic static load rating C0 | 108 kN |
| Fatigue load limit Pu | 3.8 kN |
| Limiting speed (mechanical) | 2400 rpm |
| Operating temperature | -30 to +110 °C |
| Mass | 5100 g |
| Manufacturer designation | SKF 6318-2RS1 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-24 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-24
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 & 6300-series range
| Bore d | 3.543 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 1.693 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 50 mm |
| Smallest bore in 6300-series | 10 mm |
| Largest outer diameter in 6300-series | 400 mm |
| Width range across 6300-series | 11–78 mm |
| Bore position in 6300-series (smallest first) | 19 of 30 |
| Bore above smallest 6300-series size | 80 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6318 | ISO 15 | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range. Brand-specific OEM equivalents pending multi-source data. |
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 6318-2RS model number is decoded
In the 6300-series (ISO 15 diameter series 3) the last two digits encode the bore: 6318 carries bore code 18 = 90 mm. Outside diameter 190 mm and width 43 mm come from the ISO 15 boundary-dimensions general plan. Suffix -2RS denotes two contact-type elastomer seals over a lifetime grease fill; the sealing lips add drag compared with open or shielded versions. For normal-load mounting with a rotating inner ring on a 90 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. SKF's contact-seal catalogue number is 6318-2RS1 (older text: -2RS1), mapped here from the industry-neutral -2RS spelling.
Typical equipment & failure modes
Common applications
- heavy conveyors
- pulp and paper machinery
- medium and heavy industrial drives
- large gearboxes
Known failure patterns
- seal-lip hardening and loss of pre-grease in sustained high-temperature service
- grease-life expiry in the sealed-for-life cavity (no relubrication path)
- false brinelling from vibration while the shaft is stationary
- fretting corrosion on a loose shaft seat
Selection pitfalls — read before you substitute
- Mount this 90 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 63xx medium series gains rating at 90 mm bore through a 190 mm OD and 43 mm width; the heavier rolling elements also trade away some speed versus a 6218.
- Contact seals add drag and heat: 6318-2RS runs slower and cooler-limited than the open 6318; rubber lips are generally limited to roughly 80–110 °C continuous depending on grease, and C3 clearance is the common hot-duty choice.
- Never wash a sealed 6318-2RS in solvent or press it home via the outer ring; solvent destroys the grease thickener and mounting force through the seal deforms the lip.
- Shaft and housing fillets must clear the bearing chamfer so the 43 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
- SKF catalogues the contact-sealed version as 6318-2RS1 (older printings may read -2RS1); it is shipped pre-greased and its 2400 r/min limiting speed is set by seal-lip drag and grease life versus the open bearing's 7500 r/min thermal reference speed. The single-seal catalogue number is 6318-RS1, used where one shaft side needs external relubrication.
- A one-seal execution 6318-RS1 exists for arrangements that lubricate through the open side; fitting 6318-2RS1 instead means lifetime grease and no external oil supply — mixing the two in the same shaft can starve the sealed position.
- The 151/108 kN ratings here are SKF Explorer-class figures from catalogue PUB BU/P1 17000/1 EN (Oct 2018); SKF can revise internal geometry and ratings without changing the designation, so treat the catalogue version and date as part of the specification and re-verify for critical drives.
Frequently asked questions
What are the dimensions of a 6318-2RS bearing?
A 6318-2RS deep-groove ball bearing has a 90 mm bore, 190 mm outer diameter and 43 mm width (3.543 × 7.48 × 1.693 in), per ISO 15 boundary dimensions. It is fitted with two contact rubber seals and is normally pre-greased. Geometry-based estimated mass is about 4825 g for a steel-cage unit; catalogue masses vary slightly with seal and cage design.
How does the 6318 bore code work?
The last two digits of 6318 are bore code 18, giving 18 × 5 = 90 mm bore. The 190 mm outside diameter and 43 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the 2RS suffix on 6318-2RS mean?
2RS means two contact elastomer seals, one each side, usually over a lifetime grease fill. Sealing against dust and moisture is better than ZZ shields, but the lip drag lowers the speed and temperature ceiling.
How does the 6300 compare with other series at the same 90 mm bore?
The '3' is the medium diameter series: 190×43 mm, 50.0 mm radial section at 90 mm bore, carrying more load than a 6218 but needing a larger housing bore and giving up some speed.
What is the SKF designation and catalogue data for 6318-2RS?
In the SKF Rolling Bearings catalogue this size is listed as 6318-2RS1 — two contact elastomer seals over a lifetime grease fill, 90×190×43 mm per ISO 15. Quoted values: C 151 kN, C0 108 kN, Pu 3.8 kN, limiting speed 2400 r/min, mass 5100 g. Brand suffixes (2Z, 2RSH) differ from the industry-neutral spelling 6318-2RS.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-24. Read our editorial & correction policy.