The HD Spindle bearings are Engineered to Perform. Our Spindle Bearings are designed specifically for Mower Blade Spindles, and High-Speed Applications. Precision Machined from the Highest Quality Steel for Superior Accuracy and smooth operation. The Improved Design Includes Critical C3 Clearances to allow for thermal expansion. The C3 Clearances are combined with Wear-Resistant High Temperature Synthetic Grease to Effectively Reduce Friction. The Result is a Cooler Operating Temperature and Long Bearing Life. Better Quality, Longer Life, and most importantly, Less Downtime.