The HD Wheel Bearings are Engineered to provide Maximum Performance for the Most Demanding Applications. HD Switch Wheel Bearings are Built with C3 Clearances Designed Specifically for Axle Applications. The C3 Clearances combined with High Temperature Grease reduces Friction. The Result is a Cooler Operating Temperature and Extend Bearing Life. Our High Temperature Specialty Grease, C3 Clearances and World Class Quality Make The HD Switch a Best in Class Option - Buy with Confidence. Each Precision Machined Bearing is made using the Highest Quality Steel to Provide Superiour Accuracy and Reduced Friction. By minimizing the amount of friction we are able to Increase Bearing Life, and more importantly, Decrease Downtime. Better Quality, Longer Life, Less Downtime.