Spherical plain bearings & rod ends: types, dimensions & brand filters
Sliding spherical surfaces accommodate articulation; rod ends add a threaded or shanked mounting.
On this page7 sections ⌄
What is this bearing type?
A spherical plain bearing accommodates angular movement through sliding spherical surfaces rather than balls or rollers. A rod end packages a spherical joint in an eye with a threaded or shanked connection.
| Part or design | What it does | What to verify |
|---|---|---|
| Spherical sliding pair | Provides articulation. | Identify the actual material pair and maintenance requirement. |
| Rod-end eye / shank | Connects the joint to a linkage. | Compare thread diameter, pitch and hand as well as eye dimensions. |
| Bore and ring width | Define only part of the envelope. | Also check articulation clearance and the surrounding mounting. |
On a small screen, scroll the table horizontally to read all three columns.
Variants that change the answer
A steel/bronze, steel/steel or lined design must retain its own lubrication and loading rules. A model described as maintenance-required must not be relabelled maintenance-free from its shape.
What the family name cannot tell you
A rod end and a loose spherical plain bearing with the same bore are not equivalent assemblies. Thread hand and mounting length can prevent substitution even when the joint diameter matches.
Identify the exact part before comparing
- Separate the bearing number from the complete rod-end assembly number.
- Record sliding material, lubrication requirement and allowable movement.
- Compare all connection dimensions and the exact load direction before selecting a candidate.
Technical reference basis: SKF: Spherical Plain Bearings and Rod Ends; SIKAC 8 M record. Explanation and lookup workflow: BearingScope. Manufacturer-specific limits remain attached to the exact product record.
Spherical plain bearings and rod ends: bore, thread, articulation and maintenance
A spherical plain bearing accommodates angular movement through sliding spherical surfaces. A rod end packages such a joint in an eye with a shank. Identify both the bearing interface and the shank connection; one diameter does not describe the whole assembly.
Spherical plain bearing, rod end, heim joint and spherical roller
| Name | Construction or function | Identification boundary |
|---|---|---|
| Spherical plain bearing | Inner and outer members with mating spherical sliding surfaces | No rolling balls or rollers between those working surfaces. |
| Rod end / spherical rod end | A spherical joint in an eye housing with a connection shank | The body, thread and articulation envelope are part of its identity. |
| Heim joint / rose joint | Common names used for a spherical rod-end joint | Not a unique size, thread standard, material or capacity. |
| Spherical roller bearing | Rollers running between raceways, normally for rotating-shaft support | Not interchangeable with a spherical plain bearing. |
| Vehicle ball joint | A vehicle-specific joint assembly and attachment design | A generic rod-end catalogue is not vehicle fitment evidence. |
On a small screen, scroll the table horizontally.
Male versus female, right-hand versus left-hand
Male means an external shank thread; female means an internal threaded connection. Right- and left-hand versions are separate part identities. The spherical bore is the pin or bolt interface, while the shank thread connects the rod end to the linkage. Those dimensions need not match.
| Field | What to record |
|---|---|
| Bearing bore d | Nominal pin diameter, in mm or inches. |
| Thread G | Diameter, pitch or threads per inch, thread standard and handedness. |
| Thread engagement | Usable engagement and adjustment limits specified for the assembly. |
| Centre distance | Eye centre to the stated reference face; do not mix overall length with centre height. |
| Locking and retention | Specified jam nut, fastener, spacer and locking method. |
On a small screen, scroll the table horizontally.
In the SKF catalogue examples below, a 15 mm bore uses an M14 shank thread. Searching only for a '15 mm rod end' therefore does not establish a 15 mm thread. Inch and metric threads with similar diameters must not be forced together.
Verified metric examples: bore and thread are separate dimensions
The following SKF catalogue examples are steel/PTFE sintered-bronze rod ends. Values are nominal millimetres except the metric thread designation. B is inner-ring width; h is the listed eye-centre height, not total length. These examples do not describe every SKF rod-end series.
| SKF right-hand model | Connection / left-hand counterpart | Bore d | Thread G | B / h |
|---|---|---|---|---|
| SI 6 C | Female / SIL 6 C | 6 | M6 | 6 / 30 |
| SI 8 C | Female / SIL 8 C | 8 | M8 | 8 / 36 |
| SI 10 C | Female / SIL 10 C | 10 | M10 | 9 / 43 |
| SI 15 C | Female / SIL 15 C | 15 | M14 | 12 / 61 |
| SA 8 C | Male / SAL 8 C | 8 | M8 | 8 / 42 |
| SA 15 C | Male / SAL 15 C | 15 | M14 | 12 / 63 |
On a small screen, scroll the table horizontally.
A useful contrast is SKF SIKAC 8 M: its published bore is also 8 mm and its female thread is M8, but its inner-ring width is 12 mm rather than the SI 8 C table's 8 mm. SIKAC 8 M is a steel/bronze relubricated construction. Similar bore and thread do not prove identical width, material or maintenance.
Numerical basis: SKF Spherical Plain Bearings and Rod Ends, printed pages 194 and 196; SIKAC 8 M public product record. Confirm the current complete drawing, tolerances and availability before designing a replacement.
Steel/steel, steel/bronze and PTFE-lined joints
The sliding pair, seals and specific product design determine lubrication. A lined maintenance-free joint and a relubricated metal-on-metal joint can share nominal dimensions without sharing service instructions. 'Sealed' does not automatically mean lifetime lubrication, and 'steel/steel' alone is not enough to infer the maintenance schedule.
| Construction question | Required evidence |
|---|---|
| What contacts the inner member? | Steel, bronze or a specified lining/fabric—not only the outside housing material. |
| Is relubrication required? | The exact catalogue instructions and access path. |
| Is added lubricant permitted? | Material compatibility and the maker's dry-running or lubricated specification. |
| What protects the contact? | Seal design, contamination conditions and inspection limits. |
On a small screen, scroll the table horizontally.
SKF has published design-specific extended-life steel/steel exceptions, so blanket statements that every steel/steel joint needs the same regreasing schedule are misleading. Likewise, maintenance-free does not mean wear-free or inspection-free.
Radial load, axial load and permissible tilt
Separate force through the eye from angular movement of the joint. A published radial load rating is not a general allowable axial load, and a catalogue tilt angle is not unlimited movement in a mounted bracket. Spacers, shoulders and the rod-end body can reduce the usable articulation.
- Resolve the linkage force and any bending or shock at the shank.
- Identify how load acts relative to the bearing bore and sliding surfaces.
- Check the exact manufacturer's rating definitions, load direction and service factors.
- Check angular motion throughout the mechanism's travel, including interference with spacers and fasteners.
- Verify thread engagement, locking and structural limits of the rod-end body as well as the bearing contact.
A dynamic or static catalogue rating is not automatically the assembly's safe working load. No universal tilt angle, shank bending capacity or safety factor is supplied here.
Measurement and mounting checklist
- Support and isolate the mechanism before releasing a loaded linkage.
- Photograph markings and record male/female form, thread hand, pitch and original adjustment position.
- Measure bore, inner-ring width, housing width/diameter, eye-centre distance and shank dimensions separately.
- Inspect the mating pin and spacers; fastening must not unintentionally prevent the intended articulation.
- Follow the assembly-specific engagement, torque, lubrication and retention procedure.
- Check free movement and interference through the full permitted travel before returning the equipment to service.
This is an identification checklist, not instructions to modify a vehicle suspension or steering joint. Unknown machine torque and engagement requirements remain unresolved inputs.
Where rod ends and spherical plain bearings fit
| Need | Why this construction may be relevant | Next check |
|---|---|---|
| Linkage with changing alignment | The eye joint permits bounded articulation | Oscillation, load reversal, contamination and shank connection. |
| Heavy pivot or cylinder eye | A spherical plain contact can accommodate angular movement | Actual load direction, lubrication and housing retention. |
| Rotating shaft with continuous high-speed duty | Do not select a rod end just because its bore fits | Determine whether a rolling bearing or a designed fluid-film support is required. |
| Automotive or aircraft replacement | Assembly identity and approval dominate | An equivalent-looking catalogue rod end is not a fitment or certification. |
On a small screen, scroll the table horizontally.
Comparing two rod ends without losing important differences
Keep brand, complete designation, bore, thread, width, centre height, sliding pair and lubrication mode in separate fields. If one product lacks a value, show it as unknown rather than copying from a similarly named part. Compare permissible angles and ratings only when their definitions and operating conditions match.
| Possible match | Why it is not yet an interchangeable part |
|---|---|
| Same bore | Thread, width and articulation may differ. |
| Same thread | The bearing size, body strength and centre height may differ. |
| Same envelope | Lining, lubrication, clearance and rating basis may differ. |
| Same generic name | Brand-specific suffixes can describe materially different constructions. |
On a small screen, scroll the table horizontally.
Questions to settle before selecting a model
Is a spherical plain bearing a ball bearing?
No. Its spherical working surfaces slide. A spherical roller bearing and a recirculating ball bushing use rolling elements and are different families.
Is a 15 mm rod-end bore always an M15 thread?
No. The SKF SI 15 C and SA 15 C examples shown here have a 15 mm bore and M14 thread. Read both fields.
Can male and female rod ends replace one another?
Not directly. The shank connection and installed geometry differ; adapters or linkage changes require a separately verified design.
Should I grease a PTFE-lined rod end?
Follow the exact product instructions. Do not import the lubrication procedure of a metal-on-metal joint into a dry-running lined joint.
Reviewed 2026-10-01. Technical basis: SKF Spherical Plain Bearings and Rod Ends, pp. 194 and 196; SKF SIKAC 8 M Product Record; SKF Extended Life Plain Bearings; SKF TX-Line Spherical Plain Bearings. Original BearingScope explanation and checklists. General guidance is not a model-specific installation instruction or replacement approval.
Where this family is used
Oscillating joints, linkages and hydraulic cylinders.
Read equipment selection guides →Selection and interchange checks
Check sliding pair, lubrication requirement, articulation angle, load direction and thread hand.
Full verification checklist →Spherical plain bearings & rod ends — actual products
First 12 records. Open all results to filter brands and technical attributes. These are search candidates, not approved replacements.
| Brand / complete designation | Type | d×D×B (mm) | Closure | Original precision | Clearance |
|---|---|---|---|---|---|
| SKF365049 BA | Angular contact spherical plain bearing, requiring maintenance, metric sizes | 30.162×64.292×— | Without | Not reported | Not reported |
| SKF365049 CB | Angular contact spherical plain bearing, maintenance-free, metric sizes | 30.162×64.292×— | Without | Not reported | Not reported |
| SKF365208 | Angular contact spherical plain bearing, maintenance-free, metric sizes | 40×80×— | Without | Not reported | Not reported |
| SKF365442 | Radial spherical plain bearing | 19.05×39×— | Without | Not reported | Not reported |
| SKFBLAB 367562 B | Angular contact spherical plain bearing, requiring maintenance, metric sizes | 25×47×— | Without | Not reported | Not reported |
| SKFBLAB 367563 B | Angular contact spherical plain bearing, requiring maintenance, metric sizes | 28×52×— | Without | Not reported | Not reported |
| SKFBLRB 365214 B-2RS | Radial spherical plain bearing, customized design | 45×75×— | Seal on both sides | Not reported | Not reported |
| SKFBLRB 365214 F | Radial spherical plain bearing, customized design | 45×75×— | Without | Not reported | Not reported |
| SKFBLRB 365216 A-2RS | Radial spherical plain bearing, customized design | 60×100×— | Seal on both sides | Not reported | Not reported |
| SKFBLRB 366474 A | Radial spherical plain bearing, customized design | 25.4×53.975×— | Without | Not reported | Not reported |
| SKFBLRB 366481 | Radial spherical plain bearing | 24×42×— | Without | Not reported | CN |
| SKFBLRB 366739 A | Radial spherical plain bearing, customized design | 45×68×— | Seal on both sides | Not reported | Not reported |
— = not recorded. Width conventions differ for tapered assemblies, thrust bearings and mounted units. Always inspect the dimensional drawing.
Filter all 2,282 records →All recorded subtypes in this family
Original catalogue descriptions are preserved in the records. Identical display names, including singular/plural variants, share one combined entry. Selecting a subtype opens its brand and technical filters.
No subtype matches this text.
Reference basis & data limits
Manufacturer terminology is retained in the product records. Technical reference basis: JTEKT Basic Bearing Knowledge (boundary dimensions, tolerance classes and lubrication); NSK Bearing ABCs (lubrication, designations and clearance); NTN technical FAQs (closure codes and component interchange); SKF rolling-bearing selection and maintenance references.
Selection workflows and catalogue grouping are BearingScope editorial aids. Verify the current drawing and application requirements before using a candidate. Missing database information is not converted into an assumed match.