Factory Five Racing Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
259 Posts
Discussion Starter · #1 ·
I've had a bumpsteer problem since day one. Here's my set up... Mark II, stock spindles and LCAs, Flaming River 18:1 rack, offset bushings, Forte's bump steer kit. Also, it's probably good to note that I am a steering novice.

I built a bumpsteer measuring tool, springs/shocks are removed, wheels on the ground on layers of wax paper.

Installing the tie rod from below using no spacers, with the rack at its lowest position produced a lot of bump-out. I was getting bump-out during compression for the entire travel of the suspension, so I figured I'd need to raise the outer end of the tie rod, relative to the inner end (per the info on the FAQ page]. So, I moved the rack to its highest position and mounted the tie rod from above, with no spacers. This reversed the problem and produced a whole bunch of bump-in [i.e. the outer end of the tie rod was too high, relative to the inner end]. So, I can't get the tie rod end high enough with the rack down, or low enough with the rack up. In other words, I can't find a solution. I figure I must be doing something wrong.

Any ideas?

Thanks.
- Steve
 

·
FFCobra Fanatic
Joined
·
2,600 Posts
Did you make sure that the rack is centered relative to the lower control arms. I pulled the boots back and centered the inner joints to the control arms, even on both sides. If not centered, then one side will swing a longer arc than the other. I don't know how much this will help but it can't hurt.
 

·
Registered
Joined
·
690 Posts
My Mk I, w/'93 spindles, bumpsteer was the same. Looked like the tie rod wanted to be "in" the steering arm. I added offset rack bushings to raise the rack, then put the tie rods on top of the arms.
 

·
Registered
Joined
·
259 Posts
Discussion Starter · #4 ·
I centered the rack by marking steering wheel travel limits and then putting the wheel at the midpoint. May not be exact, but it should be close.

- Steve
 

·
Premium Member
Joined
·
16,561 Posts
Steve,
Need to know what's happening in both compression and extension from the normal ride height position (from -3" to + 3"). Don't need measurements just what it is doing. With the stock rack length you cannot get it perfect since the rack length is too short (resulting in a tie-rod that is too long). So it will always cause some degree of toe out even if the height is good. What are you running for static toe in. Not sure if this will help but lot's of info here:

http://www.ffcars.com/ubb/ultimatebb.php/ubb/get_topic/f/1/t/066976/p/1.html

Cheers, Rod
 

·
Registered
Joined
·
1,043 Posts
When I was setting up my front end, I had the car on jack stands and clamped a laser pointer to a rotor so that it shined on the wall. Then moved the control arms up and down and noted how the spot moved. Very easy to see what's happening and where.
 
1 - 6 of 6 Posts
Top