SKF 6005 2RS C4 25x47x12 Deep Groove Ball Bearing

What Is the SKF 6005 2RS C4 Bearing?

SKF 6005 2RS C4 is a single-row deep groove ball bearing with dimensions 25x47x12 mm, seals on both sides and C4 radial internal clearance. The C4 clearance class is greater than Normal and C3 clearance. This execution is intended for applications where operating conditions, interference fits or temperature differences can significantly reduce the bearing's internal clearance during operation.

Technical Specifications

Manufacturer: SKF

Basic designation: 6005

Bearing type: Deep groove ball bearing

Design: Single row

Bore diameter d: 25 mm

Outside diameter D: 47 mm

Width B: 12 mm

Dimensions: 25x47x12 mm

Bore type: Cylindrical

Rolling elements: Balls

Number of rows: 1

Sealing: Both sides

Radial internal clearance: C4

Load direction: Radial and axial in both directions

Lubrication: Grease lubricated in sealed versions

What Does C4 Mean in an SKF Bearing?

C4 indicates radial internal clearance greater than C3. It is an internal clearance classification and does not indicate a higher bearing quality or precision class.

The relevant clearance sequence is:

Normal < C3 < C4

The initial internal clearance is important because mounting fits and operating temperatures can reduce the clearance available when the bearing reaches its normal operating condition.

C4 should therefore be selected when required by the machine design or bearing arrangement.

C4 vs C3 Internal Clearance

C3 and C4 are different radial internal clearance classes.

C3: radial internal clearance greater than Normal.

C4: radial internal clearance greater than C3.

Although SKF 6005 bearings with Normal, C3 and C4 clearance have the same basic 25x47x12 mm dimensions, they should not automatically be considered interchangeable.

The correct clearance class depends on the operating conditions of the bearing arrangement.

Why Is C4 Clearance Used?

Radial internal clearance can decrease after mounting and during operation.

Important factors include:

• Interference fits
• Expansion of the inner ring
• Compression of the outer ring
• Temperature differences between bearing rings
• Operating temperature
• Shaft and housing conditions

A larger initial clearance can compensate for a significant reduction in clearance under specified operating conditions.

C4 is therefore used only where the bearing arrangement requires this increased initial radial clearance.

What Does 2RS Mean?

2RS is a widely used commercial designation for a bearing equipped with seals on both sides.

For SKF bearings, the exact manufacturer suffix should be checked because SKF uses specific suffixes for particular sealing designs.

The seals primarily help to:

• Retain lubricant inside the bearing
• Limit contaminant ingress
• Protect the rolling elements
• Protect the raceways
• Reduce maintenance requirements in suitable applications

For exact replacement, the complete designation marked on the original SKF bearing should be verified.

SKF 6005 Deep Groove Ball Bearing Design

The 6005 belongs to the family of single-row deep groove ball bearings.

Its deep raceway geometry enables the bearing to accommodate:

• Radial loads
• Axial loads in one direction
• Axial loads in the opposite direction
• Suitable combined radial and axial loads

Deep groove ball bearings are characterized by relatively low friction and suitability for high rotational speeds.

SKF 6005 Dimensions

The principal dimensions of the SKF 6005 are:

Bore diameter d: 25 mm

Outside diameter D: 47 mm

Width B: 12 mm

The dimensional designation 25x47x12 mm remains the same for standard 6005 variants with different internal clearance classes. C4 changes the internal clearance, not the basic mounting dimensions.

Load Capability

The SKF 6005 deep groove ball bearing is primarily designed for radial loads, but its raceway geometry also allows it to accommodate axial loads in both directions.

Actual permissible loads depend on:

• Bearing execution
• Internal clearance
• Rotational speed
• Shaft and housing fits
• Lubrication
• Operating temperature
• Required service life

Engineering calculations should always use catalogue data for the exact SKF bearing designation.

Sealed Bearing Construction

The sealed version incorporates sealing elements on both sides of the bearing.

This configuration helps protect the bearing interior against contaminants while retaining the factory-applied lubricant.

Sealed bearings are particularly useful where regular relubrication is difficult or where the bearing requires additional protection from its operating environment.

The exact sealing characteristics depend on the specific SKF seal design.

Applications of SKF 6005 2RS C4

The C4 execution should be used in applications where increased radial internal clearance is specifically required.

Depending on the machine design, such conditions may occur in:

• Electric motors
• Industrial drives
• Gearboxes
• Industrial machinery
• High-temperature bearing arrangements
• Applications with tight interference fits
• Equipment with significant temperature differences between bearing rings
• Special rotating machinery

C4 should not be selected simply because it provides more clearance. The required clearance class should correspond to the operating conditions and equipment specification.

Temperature and Internal Clearance

Temperature differences between the inner and outer rings can change the bearing's operating clearance.

If the inner ring operates at a higher temperature than the outer ring, thermal expansion can reduce the radial internal clearance.

This is one reason why a bearing with increased initial clearance may be specified for particular applications.

However, C4 does not mean that the bearing itself is automatically a high-temperature bearing. Temperature capability also depends on seals, lubricant, cage and other bearing components.

Selecting an SKF 6005 2RS C4 Replacement

When selecting a replacement, verify:

Basic designation: 6005

Dimensions: 25x47x12 mm

Bearing type: Single-row deep groove ball bearing

Sealing: Both sides

Radial internal clearance: C4

Manufacturer: SKF

Operating requirements: Load, speed, temperature and fits

The C4 suffix is technically significant. A 6005 bearing with Normal or C3 clearance may have identical external dimensions but different internal operating characteristics.

Can C4 Be Replaced by C3?

A 6005 C4 should not automatically be replaced with a 6005 C3.

C4 has greater radial internal clearance than C3. If C4 was specified to compensate for interference fits, thermal expansion or other operating conditions, installing a bearing with lower initial clearance can result in insufficient operating clearance.

Any change in clearance class should be based on the machine manufacturer's specification or an engineering evaluation of the bearing arrangement.

Installation Considerations

Before installation, verify:

• Shaft diameter and tolerance
• Housing bore and tolerance
• Interference fits
• Required C4 clearance
• Shaft and housing condition
• Bearing alignment
• Cleanliness of mounting surfaces

Mounting force should be applied only to the ring being fitted with an interference fit. Force should not be transmitted through the balls and raceways.

Frequently Asked Questions FAQ

What are the dimensions of SKF 6005 2RS C4?
The bearing has a 25 mm bore diameter, 47 mm outside diameter and 12 mm width.

What does C4 mean?
C4 indicates radial internal clearance greater than C3.

Does C4 mean higher bearing quality?
No. C4 defines the internal clearance class, not bearing quality or precision.

Is C4 greater than C3?
Yes. The clearance sequence is Normal < C3 < C4.

Does C4 change the 6005 bearing dimensions?
No. The basic dimensions remain 25x47x12 mm.

Frequently Asked Questions from Engineers and Maintenance Technicians

Can SKF 6005 C4 be replaced with 6005 C3?
Not automatically. The two bearings have different radial internal clearance classes even though their mounting dimensions are identical.

Why would an electric motor require C4 clearance?
Specific motor designs may require increased initial clearance because of interference fits, temperature differences or other operating conditions. The motor manufacturer's specification should be followed.

Is SKF 6005 C4 a high-temperature bearing?
Not necessarily. C4 only specifies increased radial internal clearance. Temperature capability depends on the complete bearing execution, including seals and lubricant.

Does 2RS mean the bearing is sealed on both sides?
Yes, 2RS is commonly used commercially for an execution with seals on both sides. For SKF, the exact manufacturer sealing suffix should also be verified.

Can I select a replacement using only the 25x47x12 dimensions?
No. The bearing type, sealing configuration, C4 internal clearance and complete SKF designation should also be checked.