Bump steer Q

[sfwilliams@comcast.net (Scott F. Williams)]

Brian asked:
> I know it comes from cars being lowered and all, but what
> exactly is bump steer, what does it feel like?  Thanks in
> advance for your replys.

Bump steer is the (usually undesired) change in front wheel toe when the
suspension goes through its range of travel. For simplicity's sake, let's
also include roll steer in this discussion. (They're the same thing, except
one occurs when the suspension moves around due to bumps in the road and the
other when the car rolls while cornering.)

Suppose you're driving in a straight line down the road. You drive into some
furrows where the big 18-wheelers have compressed the asphalt. What happens?
The car wanders nervously and you have to hold it straight. That happens
because your wheels are literally forced to steer in different directions as
the suspension moves up and down. Or, in the case of the roll steer, you
turn into a corner and the car leans. You turn to the right, let's say, but
the front wheels point to the left. You experience the effect as understeer.

This is really an oversimplification, but it should give you the basics of
what this is all about. I've worked out a solution for curing much of this
problem, but it'll take a little while for me to actually make the parts.
We'll probably have something by Cincy time, though.
--
Scott F. Williams
NJ Scirocco nut
'99 Subaru Impreza 2.5 RS
Mazda 323 GTX turbo "assaulted" vehicle
Golf GTI 16v "rollycar"
ClubVAC: "Roads found. Drivers wanted."