SKF BR930661 Wheel Bearing and Hub Assembly (X-Tracker Design) The X-Tracker Wheel Bearing Assembly Is So Good That It's Used On Many High Performance Vehicles Manufactured Using A Unique Bearing Arrangement Which Provides Strength, Performance, And Long Life Improved Camber Stiffness Results In Reduced Brake Wear Each X-Tracker Hub Is 100% Tested To Actual OE Specifications