To minimize bump steer the placement of the tie rods are critical. There are several
packaging issues to considerate. The placement of the steering rack gives the height of
the inner pivot points for the tie rods. Since the steering rack was to be mounted in the
upper part of the frame the solution was to have the tie rods in the same plane as upper
control arms. Theoretically this solution will give zero bump steers if the tie rods are
exactly in plane with the upper control arms. It is desired to have adjustable Ackermann
to optimize the car for different driving events. So a span from 0% Ackermann to 100%
Ackermann is wanted, negative Ackermann is used on high-speed race cars only as
described in section 2.8, and due to this the tie rods have to be placed in front of the
upper control arms as seen in Figure 4.8. This will cause the compliance effects to work
in a negative way. But if the tie rod were to be located behind the upper control arms it
would result in too less adjustability of the Ackermann geometry