UJK Motorcycle Bearings: Precision Engineered for Peak Performance
At UJK, we design and manufacture high-performance motorcycle bearings built to withstand extreme speeds, high loads, heavy vibrations, and challenging environmental conditions. Whether for OEM manufacturing or global aftermarket distribution, UJK motorcycle bearings deliver superior durability, ultra-smooth rotational performance, and extended service life.
Product Series & Technical Features
1. Motorcycle Wheel Hub Bearings
Designed for high load capacity, smooth rotation, and superior resistance to water, mud, and dust.
Key Features: High-precision steel balls, optimized deep-groove geometry, dynamic sealing solutions (2RS / LLU / DDU rubber seals) preventing contamination and retaining grease.
Common Applications: Front and rear wheel hubs.
2. Motorcycle Transmission / Gearbox Bearings
Engineered to operate continuously under heavy mechanical stress, intense torque, and high operating temperatures in oiled environments.
Key Features: High fatigue strength, optimized internal clearance (e.g., C3 clearance), high-purity bearing steel, and reinforced retainers for high-rpm stability.
Common Applications: Main shaft, countershaft, drive gear, and gearbox transmission assemblies.
3. Motorcycle Crankshaft Bearings
Built for extreme revolutions per minute (RPM) and high-impact thermal expansion within the engine core.
Key Features: Precision-matched C3/C4 clearance to prevent thermal seizure, special high-speed cages (polyamide/steel), and high-frequency induction hardened races.
Common Applications: 2-stroke and 4-stroke engine crankshaft support.
4. Motorcycle Steering Stem / Head Bearings
Engineered to deliver smooth maneuverability, precise handling, and maximum impact absorption under heavy braking and rough road conditions.
Key Features: Tapered roller designs or high-load deep groove/angular contact ball configurations; superior impact resistance and anti-pitting durability.
Common Applications: Upper and lower steering stem/headstock assemblies.
Popular & Commonly Used Models
Below is a reference list of popular, fast-moving UJK motorcycle bearing part numbers:
1. Wheel Hub Bearings (Deep Groove Ball Bearings)
| Model / Part No. | Standard Dimensions (d x D x B) mm | Sealing / Clearance Types |
| 6201-2RS | 12 x 32 x 10 | Double Rubber Seal / C3 |
| 6202-2RS | 15 x 35 x 11 | Double Rubber Seal / C3 |
| 6203-2RS | 17 x 40 x 12 | Double Rubber Seal / C3 |
| 6204-2RS | 20 x 47 x 14 | Double Rubber Seal / C3 |
| 6301-2RS | 12 x 37 x 12 | Double Rubber Seal / C3 |
| 6302-2RS | 15 x 42 x 13 | Double Rubber Seal / C3 |
| 6004-2RS | 20 x 42 x 12 | Double Rubber Seal / C3 |
2. Transmission & Engine Shaft Bearings
| Model / Part No. | Standard Dimensions (d x D x B) mm | Key Attributes |
| 6205 C3 / 2RS | 25 x 52 x 15 | High-speed, C3 Internal Clearance |
| 6304 C3 | 20 x 52 x 15 | Open / Shielded, High-speed Transmission |
| 6305 C3 | 25 x 62 x 17 | Reinforced Cage, High Fatigue Resistance |
| 6006 C3 | 30 x 55 x 13 | Thin Section, Compact Gearbox Design |
| 6206 C3 | 30 x 62 x 16 | Heavy Duty Transmission Shaft Support |
3. Engine Crankshaft Bearings
| Model / Part No. | Standard Dimensions (d x D x B) mm | Special Features |
| 6205 C3 / C4 | 25 x 52 x 15 | High Speed, Polyamide / Steel Cage |
| 6304 C3 / C4 | 20 x 52 x 15 | High Radial Load Capacity |
| 63/22 C3 | 22 x 56 x 16 | Special Engine Size for 125cc/150cc |
| 63/28 C3 | 28 x 68 x 18 | Specialized High-Speed Crankshaft Size |
| 62/28 C3 | 28 x 58 x 16 | Specialized High-Speed Crankshaft Size |
4. Steering Stem / Steering Head Bearings
| Model / Part No. | Type | Common Dimensions / Applications |
| 32005X | Tapered Roller Bearing | 25 x 47 x 15 mm |
| 32006X | Tapered Roller Bearing | 30 x 55 x 17 mm |
| 30203 / 30204 | Tapered Roller Bearing | Standard Steering Stem Sets |
| SSH901 / SSH902 | Tapered Steering Set | Universal Japanese & Scooter Fitments |
Why Choose UJK Motorcycle Bearings?
Premium Raw Materials: High-carbon chromium bearing steel (GCr15 / AISI 52100) for superior wear resistance.
Advanced Sealing Technology: Specialized rubber compounds effectively seal in synthetic grease and block out grit, water, and debris.
Precision Engineering: ABEC-1 / ABEC-3 (P0/P6) precision classes with optimized clearances (C3) for reduced friction and heat generation.
Comprehensive Quality Testing: Rigorous dynamic balancing, noise/vibration testing (Z2V2 / Z3V3), and strict dimensional inspection.
