Rear Super Duty Unit Bearing Cups for 40 Spline Axles with bolts on a white background
Two Rear Super Duty Unit Bearing Cups for 40 Spline Axles with text indicating cup ID size on a white background
Technical diagram of Heavy-Duty Off-Road 40 Spline Rear Axle Components with labeled parts on a white background
Illustration of Weld-on Unit Bearing Cups for Rear Axle Build components including a unit bearing, adapter cup, and various parts on a white background.
Close-up of a 2005+ Ford Super Duty Unit Bearing Conversion Kit with weld-on cups labeled.
Close-up of 2005+ Ford Super Duty Unit Bearing Conversion Kit with white plastic parts on a white background
Rear Super Duty Unit Bearing Cups for 40 Spline Axles with bolts on a white background
Two Rear Super Duty Unit Bearing Cups for 40 Spline Axles with text indicating cup ID size on a white background
Technical diagram of Heavy-Duty Off-Road 40 Spline Rear Axle Components with labeled parts on a white background
Illustration of Weld-on Unit Bearing Cups for Rear Axle Build components including a unit bearing, adapter cup, and various parts on a white background.
Close-up of a 2005+ Ford Super Duty Unit Bearing Conversion Kit with weld-on cups labeled.
Close-up of 2005+ Ford Super Duty Unit Bearing Conversion Kit with white plastic parts on a white background

Crane Axle Rear Super Duty Bearing Adapter Cups (Pair)

CA01033

$599.99
/
Shipping calculated at checkout.

The Crane Axle Rear Super Duty Unit Bearing Cups are designed to simplify custom rear axle fabrication by adapting 2005+ Ford Super Duty unit bearings into fabricated rear axle housings. These weld-on cups eliminate the need for traditional rear spindles, wheel bearing packing, spindle nuts, and oil-lubricated wheel bearings, creating a cleaner and more serviceable wheel-end solution for off-road and competition applications.

Built for high-load environments such as rock crawling, Ultra4 racing, and custom buggy fabrication, this system supports large spline axle shafts while reducing many of the common maintenance and failure issues associated with traditional spindle-based rear axle setups. By using sealed unit bearings, builders can eliminate gear oil contamination concerns and avoid spindle damage caused by broken axle shafts or wheel-end deformation.

Includes:

  • (2) Rear Unit Bearing Cups
  • Mounting Hardware
Specifications 
  • Fits 2005+ Ford Super Duty unit bearings
  • Weld-on rear axle cup design
  • Pre-bored 3.250" inner diameter
  • Can be machined to fit axle housings up to 4.00" outside diameter
  • Designed for custom fabricated rear axle housings
  • Compatible with large spline axle shaft applications
  • Eliminates traditional rear spindle assemblies
  • Made in the USA
Fitment 
Make Model Year Range Axle Application
Ford F-250 Super Duty 2005+ Rear Unit Bearing Conversion
Ford F-350 Super Duty 2005+ Rear Unit Bearing Conversion
-- Custom Fabrication Applications -- Rear Axle Unit Bearing System

Fitment Notes:

  • Designed for 2005+ Ford Super Duty unit bearings
  • Intended for fabricated rear axle housings
  • Compatible with large spline axle shaft builds
  • Supports custom off-road and race axle applications
  • Optional Wilwood rear brake kits available

Optional Add-Ons:  

Tech Insight 

Traditional rear spindle systems require wheel bearing preload adjustment, grease maintenance, and exposure to gear oil contamination during service. In extreme off-road environments, bent spindles and broken axle shafts can also complicate repairs and damage wheel-end components.

Using sealed Super Duty unit bearings simplifies the rear wheel-end assembly by eliminating spindle nuts and traditional wheel bearing service procedures. The compact sealed-bearing design improves maintenance accessibility while supporting larger axle shafts and high-load off-road use. This setup is especially popular in fabricated rear housings where simplicity, strength, and fast serviceability are priorities.

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