That fracture from what I can see by enlarging the photo bucket image, looks crystalline to me. That would point to a fatigue failure. My guess is that stress multiplication at that point may be occurring and maybe the taper should have had a radiused shoulder where it meets the conical riser, rather than what looks like a right angle. I would also wonder about what sort of the heat treatment the whole thing had, if any and what steel was used. For something like this, aircraft spec should apply where the fatigue resistance is of the order of 10⁷ load cycles and in order to test this, ultrasonic stress testing would have to be done. This might make the whole thing uneconomic.
Many thanks for posting this. It has made me decide to stick with the bump steer on my 2012 for the time being. I don't particularly like the feel of the comfort kit as it seems to introduce more understeer.
