RE: Bump Steer, Steering Components, Hemi-Joints

["Jeff Bade" <jbade@xxxxxxxxxxxxxxxxx>]

Since this is stock hight at the moment.. (even though my lifted scout
which has everything else stock is nowhere near like this)
 
Should I be looking for worn components then?  Mismatched or out of
balance tires?

-----Original Message-----
From: Steven Stegmann [mailto:steve.stegmann@domain.elided] 
Sent: Wednesday, July 02, 2003 10:12 PM
To: Jeff Bade; IHdigest
Subject: Re: Bump Steer, Steering Components, Hemi-Joints


Jeff,
 
Your use of Heim joints has nothing to do with bump steer.  On something
like a Scout there is usually only one source.  The two ends of the drag
link are not at the same elevation.  What happens is that as the wheel
end of the drag link moves up & down with suspension motion, the wheel
end describes and arc in a vertical plane.  If the drag link is level,
the left & right component of the drag link motion is minimized.  The
further the link is from level the greater the component of the motion
becomes left & right.  That's why as the axle moves up the vehicle
steers one way and steers the opposite direction when the axle moves
down.

Contrary to popular belief the shape of the drag link has no bearing on
the situation.  It is only the relative elevation of the two ends of the
drag link that matters.  The best fix is to get a pitman arm which makes
the two ends of the drag link the same elevation.