What do these rear unit bearing cups do?
These cups provide the interface between a custom rear axle housing and a 2005+ Ford Super Duty unit bearing. They are welded to the axle housing so builders can use a unit-bearing wheel end instead of a traditional spindle and serviceable wheel-bearing assembly.
Why use a Super Duty unit bearing on a custom rear axle?
A sealed unit bearing combines the wheel bearings and hub support into a compact assembly. This eliminates traditional spindle nuts, wheel-bearing preload adjustment, bearing packing, and oil-lubricated wheel bearings, simplifying both axle construction and wheel-end service.
Do these cups fit directly onto a 4" axle tube?
No. The cups are supplied with a 3.250" pre-bored ID and contain enough material to be machined for axle housing tubes up to 4.00" OD. The cups must be machined to match the specific housing before welding.
Are the Super Duty unit bearings included?
No. This product includes the pair of rear unit bearing cups and mounting hardware. The unit bearings, axle shafts, brakes, and other wheel-end components are selected separately for the complete axle build.
Can I use these cups with a large-spline rear axle shaft?
Yes. One of the advantages of this wheel-end configuration is its ability to support custom large-spline axle shaft applications. The axle shaft, unit bearing, drive interface, differential, and other components must all be selected as a compatible system.
