608 bearing is one of the most widely used miniature deep groove ball bearings in the world. Known for its compact 8×22×7 mm dimensions, low friction, and versatile performance, it is commonly found in skateboards, inline skates, electric motors, power tools, conveyors, and industrial equipment. This guide covers 608 bearing dimensions, load ratings, speed limits, material options, sealing types, applications, and selection tips to help engineers and buyers choose the right bearing.
608 Bearing Dimensions and Specifications
| Parameter | Value |
|---|---|
| Bearing Type | Deep Groove Ball Bearing |
| Bore Diameter (d) | 8 mm |
| Outside Diameter (D) | 22 mm |
| Width (B) | 7 mm |
| Dynamic Load Rating (Cr) | 3.3 kN |
| Static Load Rating (Cor) | 1.37 kN |
| Weight | Approx. 12 g |
| Rows | Single Row |
| Material | Chrome Steel / Stainless Steel / Ceramic |
Dimension Breakdown
- 8 mm Bore: Fits standard 8 mm shafts used in skateboards, electric motors, and small machinery.
- 22 mm Outer Diameter: Suitable for compact housings with limited installation space.
- 7 mm Width: Provides an ideal balance between load capacity and compact size.
What Does 608 Mean?
The bearing designation “608” follows the international bearing numbering system.
- 6 = Deep Groove Ball Bearing Series
- 08 = Bore Code (8 mm inner diameter)
Therefore, a 608 bearing is a single-row deep groove ball bearing with dimensions of 8×22×7 mm.
608 Bearing Construction
Inner Ring
Mounted directly on the shaft and rotates together with it.
Outer Ring
Installed inside the housing and provides the outer raceway.
Steel Balls
Reduce friction and support both radial and moderate axial loads.
Cage
Separates the balls evenly and prevents contact between rolling elements.
How Much Weight Can a 608 Bearing Hold?
One of the most common questions is how much load a 608 bearing can support.
| Load Type | Typical Rating |
|---|---|
| Dynamic Load Rating | 3.3 kN |
| Static Load Rating | 1.37 kN |
In practical applications, actual load capacity depends on speed, mounting accuracy, lubrication, shock loading, and operating conditions.
For skateboard wheels and small machinery, 608 bearings typically provide more than enough capacity for everyday use.
608 Bearing Maximum Speed
Maximum operating speed varies depending on seal type and lubrication.
| Bearing Type | Maximum Speed (RPM) |
|---|---|
| 608 Open | 40,000 |
| 608ZZ | 34,000 |
| 608-2RS | 28,000 |
Open bearings offer the highest speed capability because they generate the least friction.
Rubber-sealed bearings provide superior protection but slightly reduce maximum speed due to seal contact.
608 Bearing Weight
| Type | Weight |
|---|---|
| 608 Open | 11.8 g |
| 608ZZ | 12.0 g |
| 608-2RS | 12.2 g |
Weight may vary slightly between manufacturers and materials.
608 Bearing Material Options
| Material | Corrosion Resistance | Speed Capability | Typical Applications |
|---|---|---|---|
| 52100 Chrome Steel | Low | High | Industrial Equipment |
| 440C Stainless Steel | High | Medium | Food Machinery |
| Hybrid Ceramic | Excellent | Very High | Electric Motors |
| Full Ceramic | Excellent | High | Chemical Processing |
608 Open vs 608ZZ vs 608-2RS
| Type | Protection | Friction | Best For |
|---|---|---|---|
| Open | None | Lowest | Clean Environments |
| ZZ | Dust Protection | Low | High-Speed Applications |
| 2RS | Dust & Water Protection | Moderate | Outdoor & Harsh Conditions |
Choose 608ZZ If:
- High speed is important.
- Environment is relatively clean.
- Low friction is required.
Choose 608-2RS If:
- Dust, moisture, or contaminants are present.
- Long service life is preferred.
- Maintenance opportunities are limited.
Recommended Fits and Tolerances
Proper installation significantly affects bearing life.
| Application | Recommended Tolerance |
|---|---|
| Shaft Fit | h6 |
| Light Press Fit | k5 |
| Heavy Press Fit | m5 |
| Housing Fit | H7 |
How Long Does a 608 Bearing Last?
Bearing life depends on operating load, speed, lubrication quality, contamination level, and installation accuracy.
Theoretical bearing life is calculated using the standard L10 life formula:
L10 = (C/P)³ × 10⁶ revolutions
- C = Dynamic Load Rating
- P = Equivalent Dynamic Load
Under proper operating conditions, a quality 608 bearing can deliver thousands of hours of reliable service.
Common Applications of 608 Bearings
Skateboards and Inline Skates
The most recognized application for 608 bearings worldwide.
Electric Motors
Used in small motors requiring smooth rotation and low noise.
Power Tools
Installed in drills, grinders, and sanders operating at high speeds.
Conveyor Systems
Support rollers and pulleys in logistics and manufacturing equipment.
Fitness Equipment
Found in treadmills, exercise bikes, and various motion systems.
608 vs 607 vs 609 Bearings
| Model | Bore | Outer Diameter | Width |
|---|---|---|---|
| 607 | 7 mm | 19 mm | 6 mm |
| 608 | 8 mm | 22 mm | 7 mm |
| 609 | 9 mm | 24 mm | 7 mm |
Although similar in appearance, these bearings are not interchangeable due to different bore and outside diameters.
608 Bearing Interchange Guide
| Replacement Option | Interchangeable |
|---|---|
| 608ZZ ↔ 608-2RS | Yes |
| 608 Steel ↔ 608 Stainless | Yes |
| 608 Steel ↔ 608 Ceramic | Yes |
| 608 ↔ 607 | No |
| 608 ↔ 609 | No |
Frequently Asked Questions
Are all skateboard bearings 608?
Most skateboard wheels are designed around standard 608 bearings, although quality and materials vary significantly.
Can a 608 bearing rust?
Standard chrome steel bearings can rust if exposed to moisture. Stainless steel versions provide better corrosion resistance.
Which is better, 608ZZ or 608-2RS?
608ZZ is better for speed and low friction, while 608-2RS offers better sealing and longer service life in dirty environments.
Can I wash a 608 bearing?
Yes. Bearings can be cleaned using suitable bearing cleaners and relubricated before reuse.
What is the most common 608 bearing material?
52100 chrome steel remains the most widely used material due to its excellent balance of performance and cost.
Conclusion
The 608 bearing remains one of the most versatile miniature bearings available. With standard dimensions of 8×22×7 mm, multiple sealing options, various material choices, and excellent load capacity, it serves applications ranging from skateboards and electric motors to industrial machinery. Selecting the correct seal type, material, and precision grade ensures optimal performance and maximum service life.