A-Arm: 10 Degree Screw in Ball Joint-Slotted Shaft-Specify Steel or Aluminum Precision machine work and quality materials put JOES A-ARMS in a class of their own. These screw-in ball joint A-arms come with the standard 6 inch bolt centers and are slotted for easy adjustment. A-Arm slugs are required and they lock your caster settings in place with a selection of offset slugs. The JOES slotted A-arm shaft utilizes one aluminum slug so you can remove and replace them without losing your settings. JOES A-arms are tested on our A-arm fixture producing the most rigid part on the market. .095 tubing and close tolerences minumize flex and binds for repeatable chassis set ups. Check out the entire line of JOES A-arms. We make all the popluar configurations. Aluminum & Steel shafts, 0 or 10 degree, Bearing style are all available. Call if you need us to build you a custom a-arm.