I had some nasty bump steer on my 95 Impala SS, and I'm wondering if any of you experienced bump steer on your RWD RT Magnums.

 

What do you mean by "bump steer"??

 

Bump steer is when the Camber changes when the front end goes up and down, causing the steerind to feel vague.
It's hard to explain and easy to feel, but even harder to fix, but I guess it's not a problem on the Magnum or people whould have already complained about sloppy steering.
It might be a problem if we put wide tires in front though!

 

yeh i hate that crap..

i have wide tires on my neon.. was gettin bump steer..

tire balancing made it somewhat go away.. but sometimes i still get it.

 

What do you think the widest tires could fit in front without causing bump steer on the Magnum?
I'm thinking of going 245 or 255 max in front, should be OK, right?

 

My car bump steers with the 18x8 with 225's. The stock RT wheels. I am not convinced that its not a specific problem with my car though, none of the other magnums I drove acted this way.

 

Actually, it's not a change in camber, it's a change in toe as the suspension moves through its arc (compression and rebound). This causes a jerk in the steering wheel, hence bump, then steer.
On a street car, bumpsteer can usually be lessened or fixed with a precision alignment. On a race car, an adjustable tie rod, allowing you to change the length between the spindle and the tie rod end, will do the job. The usual procedure is to remove the spring so it won't offer any resistance, mount a special bumpsteer-measuring plate to the wheel hub, and bring the suspension up and down through its arc. You then add or subtract washers to the adjustable tie rod assembly to facilitate as close to zero toe change as possible.
Here's a picture of an adjustable tie rod end from Maximum Motorsports, a Mustang specialist:

 

I had a 96' Impala SS and I know about the bump steer problem.

It was caused by the wide tires, which in turn wore out the idler arm.

Installing MOOG (brand name) heavy duty idler arm would fix the problem.

Anytime you have wide tires on your car, they put more cornering forces on your suspension and steering parts.

Our Magnum RT's shouldn't develop that problem, unless you go to wide tires and don't upgrade your suspension parts.

Been there, done that.

Bob

 

I forgot to mention what bump steer feels like.

Your car is going down the road, the tire catches a crack or bump in the pavement.

Car wants to follow that crack, grove or bump - like it was steering itself.

Due to a little slop in the steering (i.e. Idler arm)

Bob

 

That's actually not bumpsteer. That's more due to tire tread design than anything else, or it's just an alignment issue. (A precision alignment should always be performed after changing tires or adding a wheel and tire package.)
As I described above, bumpsteer is when the steering wheel jerks due to a change in toe. If the suspension stays level while riding down the road, the toe won't change, and you won't experience bumpsteer. Only when the suspension moves up or down, causing a possible increase or decrease in toe, will you experience bumpsteer. It has nothing to do with the tires following cracks in the pavement.
Here's a good article on bumpsteer: Longacre Bumpsteer Page