[TR] [Spits] GT6 Bump Steer

[Dave1massey at cs.com]

In a message dated 8/15/2007 5:03:04 AM Central Daylight Time, 
foxtrapper at aceweb.com writes: 
> It's caused by suspension motion.  So the easy and very effective band-aid 
> is to limit suspension motion.  Most easily done with stiff springs.  Not 
> that these cars had a lot of suspension travel anyways.
> 
Correct me if I am wrong but isn't bump steer the result of the one end of 
the tie rod, connected to the steering arm on the vertical link, moves up and 
down with the suspension while the other end, connected to the steering rack 
which does not move, remains stationary (in relation to the car) causing the 
angle of the tie rod to change and hence the horizontal distance (which is the 
cosine of the angle) between the tie rod end on the rack and the tie rod end on 
the steering arm to change?  (talk about a run-on sentence!)

The only solution is to make the tie rod as long as possible making the angle 
change due to suspension movement less.  But that is not practical in our 
cars.  I had a 1987 Audi 5000 (horrible car, broke every month) that had the 
steering rack mounted high on the firewall.  The rack tie rods connected to a 
knuckle on the rack located near the center of the car.  This meant the tie rods 
were almost half the width of the car reducing bump steer as much as practical. 
 But this is not a viable option on a Triumph.

The best bet is to get a good alignment so that bump steer effects both sides 
equally.

Dave