After researching this subject extensively, and the recent threads about it, I thought it might be a good idea to make a thread to answer everyones questions on the subject.

Here are a couple pics I took comparing the 04-05 spindle to the 06-up spindle. The 06-up spindles look nearly identical to the 400ex spindle.


The 04/05 spindle is on top, 06-up on the bottom.


04/05 on the left, 06-up on the right. Notice the extra material on the 06 spindle. The spindle is notably heavier than the 04/05 spindle. Also note the location of the arm where the tie-rod attaches to the spindle. The 06-up spindle places the tie-rod attachment point closer to the upper ball joint.


04/05 on the left, 06-up on the right.



The stock 400ex hubs will bolt up to the 06-up spindles without any issues, the caliper alignment is perfect.

The 04/05 spindle will require the use of 04/05 hubs and due to caster changes, an adjustable upper a-arm is advised: I don't know this first hand, this info is based on issues posted on here, and judging by the differences in the spindles, I could foresee it being an issue.

Any other info is welcome.

Mods, make this a sticky?