What are the mechanical pros and cons of ball bearings?

Mechanical Pros & Cons of Ball Bearings

●Advantages

▸Ultra-Low Rolling Friction: Steel balls roll purely within the raceway, reducing friction resistance by over 90% compared to sliding friction in bushings. Motorcycle wheels rotate more smoothly, resulting in a noticeable increase in range.
▸Excellent Radial Stiffness: Multi-ball load-sharing structure, deformation <0.1mm when bearing the weight of the vehicle. No wheel hub misalignment during high-speed cornering, ensuring stable tire contact with the ground.
▸High Speed ​​Tolerance: Stable operation of connecting rod bearings in engines operating at 10,000 RPM (ball centrifugal force < oil film tension). The maximum speed limit of cageless full-load bearings is increased by 30%.
▸Adaptive Fine-Tuning: Self-aligning ball bearings tolerate 0.5° axial misalignment (3 times stronger than tapered roller bearings). Addresses manufacturing errors such as frame welding deformation.

●Fatal Flaws

▸Axial Vulnerability: An oblique impact to a curb → the ball bearing climbs the V-shaped raceway → the ball breaks instantly (conical roller bearings can withstand this). Steering column bearings can only withstand 200kg of axial impact (equivalent to a 70kg driver jumping and landing).
▸Shock Wave Transmission: When going over a speed bump, the vibration is amplified through point contact with the steel balls → raceway indentation (microscopically resembling a meteorite crater). Under the same conditions, needle roller bearings distribute stress through line contact.
▸Contamination Leads to Failure: A 50μm grain of sand intrudes → grooves are crushed into the raceway → irreversible abnormal noise. The lifespan of the oil seal lip decreases drastically after aging.
▸Frequency Corrosion Trap: Long-term parking causes rust at the bearing contact points → the oxide layer peels off the ball bearings upon startup → metal powder mixes with the grease.