SKF Automotive Division

X-Tracker Asymmetric Hub Bearing Unit

SKF’s X-Tracker is the most significant innovation in the global hub bearing market since the integration of ABS sensors in the 1990's. It consists of an asymmetrical, two row wheel hub bearing arrangement with the outboard bearing race a significantly larger diameter that carries more rolling elements than the inboard row. This uniquely innovative architecture increases the camber stiffness of the hub unit by as much as 70%, adds significant load carrying capacity, and extends service life. This is accomplished without need to change any of the surrounding components and without increased cost.

The most significant attribute is desired stiffness that was not previously attainable with symmetrical bearing rows. Increased stiffness enhances safety by reducing brake caliper piston knock-back, thereby improving brake response times and vehicle stability. X-Tracker has a stronger hub and higher load carrying capacity making it applicable to a wide range of vehicles from compact cars to full sized light trucks.

The innovation originated at SKF’s North American Technical Center in Plymouth, Michigan, during a design exercise to replace a light truck taper hub unit with a ball unit to achieve increased function integration, increase stiffness, and reduce cost at the same time.

The first commercial adaptation was the 2004 Dodge Durango front wheel hub unit, followed by the hubs of the 2005 Dodge Dakota. It now is used on all four wheels of the Cadillac STS-V. In the Dodge applications it is used to integrate functions, add stiffness, and reduce cost. In the STS-V it is used to increase camber stiffness for better braking and stability control of this high performance car.

Improving performance and offering value is an important part of SKF’s business and marketing strategy. X-Tracker has raised the standard of industry expectations, and SKF’s visibility.