Quote Originally Posted by Cool Cat Racing
Its not really the angle of the tie rod and spindle. True bump steer as far as suspension is concerned is caused when the control arms and the tie rods are not pivoting from the same place. When they two have two separate arcs the spindle will toe in or out because of the different distances of the two arcs. An alignment won't ever really fix this, this problem is why many nicer tie rods with Heim joints include spacers to lower the tie rod until it follows a closer arc.
Pretty much what I meant in not so many words!