I am experiencing some bump steer on certain parts of the freeway around here and it's kind of scary when the car starts to veer into another lane. Any clues as to what may help? I have a 66 coupe lowered 1-1.5 inches front and rear with a 1" front sway bar. Other than that, the suspension is stock. I am planning on replacing the idler arm and maybe the steering box to mitigate the minimal steering wheel play.

 

There is a lot of great info in this thread https://mustangforums.com/forum/clas...need-help.html

You may want to check your strut rods first.

 

Definitely check all of the suspension bushings, particularly the strut rods. Make sure the car is aligned properly as well.

The more you lower the car, the more bump steer is apparent. Tightening up any steering slop will help, but the end solution is a bump steer corrector kit.

 

Both tcp and baer make bump steer tie rod ends.

 

I had bump steer for years and could never figure it out then I got new front tires and it cured it. I am assuming the balancing of my old tires was off so I would also say make sure your tires are properly balanced.

 

I doubt that the issue with your old tires was a bad balance. You'd have had either a steering wheel shimmy (rotational) or a vertical shake as well. I suspect tramlining.

Different tires behave differently as far as tramlining is concerned, and some tire models are much worse than others. Tramlining is frequently confused with bumpsteer, but is a function of tire construction rather than suspension geometry.



stephen - I think your problem is more likely to be tramlining than bumpsteer, since it apparently occurs in a specific stretch of highway. How bad are the truck tire ruts there?


Norm

 

I failed to mention I have replaced the strut rod bushings and the car is aligned properly. I have never heard of "tramlining" before. The area(s) of the highway where it is most noticeable are where the truck tire ruts are worst. They seem to pull or puch me one way, then I steer to correct it and the slightest correction seems to push me all over the lane. Steering slop, I am sure is part of my problem.

 

Classic case of tramlining (if you've ever driven on city streets that had streetcar rails embedded, the term would make complete sense).

Anyway, it's a tire issue that has to do with the details of its construction. In addition to the actual body plies and belting, tread width and wheel width seem to have a lot to do with it, and the tire properties 'ply steer' and 'conicity' are probably involved.


Norm

 

yep. tramlining it is. bumpsteer is when steering turns on a bump or pit.
what wheels are you currently running and how old are they?

 

What is your caster setting?