The 6802 bearing is a compact deep-groove ball bearing with an inner diameter of 15 mm, an outer diameter of 24 mm, and a width of 5 mm. This metric thin-section bearing is widely used in electric bicycles, household appliances, automotive components, and precision machinery. Whether you are replacing worn bearings in an e-bike motor or selecting components for a new design, understanding the specifications, material options, and sealing types is essential for proper selection.
6802 Bearing Dimensions and Specifications
The 6802 bearing follows ISO standard dimensions. The table below summarizes its core specifications:
| Parameter | Value |
|---|---|
| Bearing Type | Deep Groove Ball Bearing |
| Inner Diameter (d) | 15 mm |
| Outer Diameter (D) | 24 mm |
| Width (B) | 5 mm |
| Weight | Approx. 7 g |
| Dynamic Load Rating (C) | 2,058 N (210 kgf) |
| Static Load Rating (Co) | 1,274 N (130 kgf) |
| Limiting Speed (Grease) | 17,000–26,000 rpm (varies by seal type) |
Open 6802 bearings lubricated with grease can reach up to 26,000 rpm, while oil lubrication permits speeds up to 31,000 rpm. Sealed variants typically operate between 17,000 and 25,000 rpm.
Material Composition of 6802 Bearing
The 6802 bearing consists of four primary components: an inner ring, an outer ring, rolling balls, and a cage (also called a retainer). The raceway groove is slightly larger than the ball radius, enabling the bearing to handle both radial loads and bidirectional axial loads through point contact.
The material selection directly impacts the bearing’s performance in different environments:
| Material Type | Rings and Balls | Cage Material | Key Characteristics |
|---|---|---|---|
| Chrome Steel | GCr15 / SAE 52100 | Steel | High hardness, wear resistance, cost-effective |
| Stainless Steel | AISI 440C | Stainless steel or 304/316 | Corrosion resistance, suitable for humid or wash-down environments |
| Hybrid Ceramic | Steel rings + Si₃N₄ ceramic balls | Steel or polyamide | Lighter weight, lower friction, higher speed capability |
Chrome steel is the most common choice for general industrial applications. For applications requiring corrosion protection, stainless steel 6802 bearings are available. Hybrid ceramic bearings use silicon nitride (Si₃N₄) ceramic balls with steel rings, offering reduced friction and lighter weight compared to full steel bearings.
Sealing Types and Selection Guide
6802 bearings are available in three primary sealing configurations: Open, Metal Shielded (ZZ), and Rubber Sealed (2RS). The suffix after the bearing number indicates the seal type.
Open (No suffix). The bearing has no sealing components on either side, allowing direct access to the rolling elements and raceways. This design is suitable for applications requiring high-speed operation with controlled lubrication systems, such as machine tool spindles and high-speed motors.
ZZ (Metal Shielded). A metal shield is pressed onto one or both sides of the bearing. Shields protect against larger debris ingress while allowing some lubricant flow. They introduce minimal friction and do not significantly limit speed. However, shields are not effective against moisture or fine dust.
2RS (Rubber Sealed). Contact rubber seals are fitted on both sides, providing superior protection against dust, moisture, and contaminants. The seals also retain pre-applied grease, enabling maintenance-free operation in many applications. However, the contact seal introduces additional friction and reduces the maximum permissible speed. Common designations include 6802-2RS, 6802LLU, and 6802DDU.
Selection Considerations
- Clean environments with high-speed requirements: Open or ZZ bearings offer the highest speed potential.
- Outdoor or dusty environments: 2RS sealed bearings provide the best protection.
- Wet or humid conditions: Stainless steel bearings combined with 2RS seals are recommended.
- High-speed motors and precision spindles: Open bearings or non-contact seal designs are preferred.
Common Applications of 6802 Bearings
The 6802 bearing’s compact size and reliable performance make it suitable for a wide range of applications across multiple industries.
Automotive Industry. 6802 bearings are found in various automotive auxiliary components, including starter motors, alternators, air conditioning blowers, and window regulator mechanisms where space is constrained but reliable rotation is required.
Household Appliances. In washing machines, dryers, vacuum cleaners, and ventilation fans, the 6802 bearing supports rotating shafts in confined spaces, contributing to quiet and efficient operation.
Electric Bicycles. The 6802 bearing is extensively used in e-bike hub motors and bottom bracket assemblies. The 15 mm inner diameter fits common electric motor shafts, while the 5 mm width accommodates compact hub designs. Many mid-drive and hub-drive e-bike motors rely on 6802 bearings for smooth power transmission.
Small Electric Motors and Generators. General-purpose fractional horsepower motors, cooling fans, and small generators often incorporate 6802 bearings for their combination of load capacity and low friction.
Scooters and Power Tools. Electric scooters, power drills, grinders, and circular saws use 6802 bearings in their motor and drivetrain assemblies to ensure consistent performance under moderate loads.
Medical and Laboratory Equipment. Centrifuges, diagnostic devices, and other precision laboratory instruments benefit from the 6802 bearing’s smooth operation and, in the case of stainless steel variants, corrosion resistance.
How to Determine the Correct Bearing Size for Your E-Bike
Selecting the correct bearing size for an electric bicycle requires careful identification. The following methods help ensure accurate replacement.
Check the Manufacturer’s Manual. Most e-bike manufacturers provide detailed parts lists or service diagrams that specify the bearing model numbers used in the motor, hub, and bottom bracket. Locate the model number (e.g., 6802-2RS or 6802ZZ) directly from the documentation.
Measure the Existing Bearing. If the manual is unavailable, remove the bearing from the assembly and measure it using a digital caliper. Record the inner diameter, outer diameter, and width. A 6802 bearing will measure 15 mm × 24 mm × 5 mm. Also note any markings on the shield or seal that indicate the model number.
Look for Part Numbers. Standard bearings are stamped with their model number (e.g., 6802, 61802). Sealing suffixes such as ZZ, 2RS, or LLU are typically printed on the shield or seal surface. If the number is worn, the measurement method provides a reliable backup.
Consult Bearing Suppliers. For confirmation, provide the measured dimensions and application details (e.g., e-bike hub motor) to a bearing supplier. Suppliers maintain cross-reference databases to match bearings across different brands.
Electric Bicycle Bearing Size Reference
Beyond the 6802 bearing, several other metric sizes are common in electric bicycle applications. The table below lists typical bearing models found in e-bike hubs, motors, and drivetrain assemblies:
| Bearing Model | Inner Diameter (mm) | Outer Diameter (mm) | Width (mm) | Common Application |
|---|---|---|---|---|
| 6800 | 10 | 19 | 5 | Small hub motors, pedal bearings |
| 6801 | 12 | 21 | 5 | E-bike motor shafts |
| 6802 | 15 | 24 | 5 | Hub motors, bottom brackets |
| 6803 | 17 | 26 | 5 | Mid-drive motor supports |
| 6804 | 20 | 32 | 7 | Larger hub assemblies |
| 6902 | 15 | 28 | 7 | Heavy-duty hub applications |
When replacing bearings in an e-bike motor, confirm the specific sealing type required. Rubber-sealed (2RS) bearings are typically preferred for e-bike applications because they protect against dust, water ingress, and retain pre-applied grease for extended maintenance intervals.
Lubrication and Maintenance Considerations
Proper lubrication is critical for achieving the rated service life of a 6802 bearing.
Grease Selection. Most sealed 6802 bearings are pre-lubricated at the factory with lithium-based grease suitable for general-purpose use. For high-speed applications, low-viscosity greases reduce friction and heat generation. For high-temperature environments, synthetic greases with a broader operating temperature range are recommended.
Speed Limits. The maximum operating speed depends on the sealing type and lubrication method. Open bearings lubricated with oil can achieve up to 31,000 rpm, while rubber-sealed variants are typically limited to 17,000–20,000 rpm. Exceeding these limits accelerates wear and can lead to premature failure.
Temperature Range. Standard steel 6802 bearings operate reliably between -40°C and 120°C. For applications exceeding this range, high-temperature greases or ceramic hybrid bearings may be required.
Replacement Intervals. In e-bike hub motors subject to frequent use, 6802 bearings typically last between 5,000 and 10,000 kilometers, depending on riding conditions, load, and environmental exposure. Routine inspection for noise, roughness, or play indicates when replacement is necessary.
Conclusion
The 6802 bearing is a versatile deep-groove ball bearing with dimensions of 15 mm × 24 mm × 5 mm, making it suitable for a wide range of compact applications including e-bike hub motors, household appliances, and precision machinery. Material options include chrome steel for general use, stainless steel for corrosion resistance, and hybrid ceramic for low-friction, high-speed applications. Seal types—Open, ZZ (metal shielded), and 2RS (rubber sealed)—allow matching the bearing to specific environmental and speed requirements.
When selecting or replacing a 6802 bearing, confirm the dimensions, verify the sealing type required by your application, and consider the operating conditions to maximize service life.
Frequently Asked Questions (FAQs)
Q1: What is the difference between ceramic and regular 6802 bearings?
A1: A regular 6802 bearing uses chrome steel for both the rings and the balls. A ceramic (hybrid) 6802 bearing uses steel rings with silicon nitride (Si₃N₄) ceramic balls. Ceramic balls are lighter and harder than steel balls, resulting in lower friction, reduced heat generation, and higher speed capability. However, ceramic hybrid bearings are more expensive and may not be necessary for standard applications.
Q2: What if the 6802 bearing I received is not ceramic?
A2: If you ordered a ceramic bearing but received a standard steel bearing, check the packaging and bearing markings first. Steel bearings are typically unmarked or marked only with the model number, while ceramic bearings often have distinctive markings indicating their material. Confirm with the supplier whether the delivered part matches your order specifications. Standard steel bearings remain fully functional for most general applications.
Q3: How can I tell if a 6802 bearing is high quality?
A3: Quality indicators include uniform rotation without roughness or noise, clear and legible markings on the bearing shield, and consistent dimensions within ISO tolerance standards. High-quality bearings from reputable manufacturers typically list their ABEC rating or ISO precision class (e.g., P0, P6) and provide a datasheet with dynamic and static load ratings.
Q4: What is the difference between 6802, 6802ZZ, and 6802-2RS?
A4: All three refer to the same 15 mm × 24 mm × 5 mm bearing dimensions. The suffix indicates the seal type: 6802 is open (no seals), 6802ZZ has metal shields on both sides, and 6802-2RS has rubber contact seals on both sides. Rubber seals provide better contamination protection but generate more friction and limit maximum speed compared to metal shields.
Q5: What does C3 clearance mean for 6802 bearings?
A5: C3 indicates increased internal radial clearance beyond standard (CN) levels. Bearings with C3 clearance are specified for applications where thermal expansion of the shaft or housing might otherwise cause preload and overheating. In e-bike motors and other applications with high operating temperatures, C3 clearance helps accommodate expansion and maintains proper bearing function.
