drwet

My '79 has a Steeroids rack and pinion setup. The steering still is a little vague. I'm trying to tighten it up a bit. Tonight I put on a Speed Direct spreader bar. Nice part. Haven't had a chance to test drive it yet though.

One of the advantages to the Steeroids setup is that it is adjustable for bump steer. I understand the concept, but how does one adjust for bump steer?

ddawson

You could buy a Bump Steer Gauge to have it perfect but I just judge it if I'm getting pump steer going down the freeway.

SH-60B

I also have a '79 with steeroids. You want the tie rods to be parallel to the lower control arm mounting points. That would be the pivot center of the ball joint and the center of the frame mounting bolts, LOL. The frame bolts, no problem, but I could only try to visualize the innards of the ball joint. I used a scale to measure from the bolt down to the tie rod and compared that to the ball joint to the tie rod and they were the same with the steeroids initial set-up instructions.

I don't see any significant bumpsteer in my car, but I just got an alignment for the steeroids and tubular upper control arms and that vague steering feel is gone.

FWIW my daily driver Oldsmobile has noticeable bump steer. Not on a racetrack, but on the Merritt Parkway Connecticut, which is the same thing

leadfoot4

You mean the Merritt parkway is really bumpy, or the traffic moves really fast......or both?

SH-60B

Awkward worded, but yes, both. I live in the left lane, that's the one that has drains. The slope into the drains extend into the roadway.

leadfoot4

Your post wasn't awkwardly worded at all......just one of those sentences that could be interpreted in two ways....the way you intended, which I fully understood, and the way a wise guy like me could have a little fun with it.

drwet

I just had a chance to test drive the car today. (Snow finally went away - why do I live in this country?) I cannot believe what an improvement that spreader bar is!!! 80% of the vagueness in my steering is gone. Still some room for improvement, but that spreader bar has got to be the best bang for the buck in Corvette handling on the planet!

SH-60B

Well that's next on my list then...

MN80Vette

A pretty good article FYI:

How to correct bump steer

leadfoot4

Good article indeed!!!

Kubs

How I normally adjust for bumpsteer is with a laser level and with the spring out. With the spring out and a jack under the control arm you can move the suspension up and down freely. Put the laser level on the spindle and have it shine on the wall or piece of poster board. You can see how much it steers in droop and compression. Adjust as necessary and then put the spring back in.

Kubs

I should have read that before posting. Very similar. Good read!

TheSkunkWorks

For those who have access to a Chevy Power book, the section on Vehicle Dynamics includes various bumpsteer curve illustrations that may prove helpful to better understanding the cause and effect side of the problem.


IMCO it's worthy of note that while bumpsteer blocks commonly on offer will tend to improve outer tie-rod end height on lowered C3s, they don't offer a fine tuning adjustment, and will necessarily result in shorter than optimal tie-rod lengths while increasing Ackerman (the latter of which is worthy of its own debate). That said, before anyone drops a bundle on new kit, there are other cost effective solutions available which don't require reengineering the entire front end. My $.02, HTH.



TSW