Hi! I own a 86 base model FC manual steering rack with a 5 lug swap, but i can remember the car having bumpsteer since the first day i got it. Over the years i replace a few parts and align the car a couple of times but it never made any difference. The car currently have poly bushing, koni inserts, t2 wheels, new tie rod ends, newer falken tires (stock size). I had the car up on a alignment rack before and the tie rod end seems to be pretty parallel to the lower control arm. If anyone have any ideal what i should about fixing the bumpsteer please let me know. Thanks!

 

Changing the ride height changes the bumpsteer.


-Ted

 

The car have stock springs with koni inserts. I think the springs ride height changed a little but i had bumpsteer problem even with tokico blues and stock springs. Could worn out steering rack bushing cause this and could it be a a normal characteristic of a manual steering rack?

 

what tire size do you have? a change in the tire size and ride height combined can completely alter the designed suspension geometry on a single arm strut suspension. the suspensions center of gravity and center of roll are totally altered with only slight changes.

 

205/55/16 i am pretty sure thats my stock size correct me if i am. Right now the rear of my car is about 1 1/2 inch half higher then stock and front is 1/2 inch higher. The koni shocks i got is just higher then my stock shocks. I am running on stock springs, hats, and bump stop on all corners. Can half an inch of front ride height change my suspension geo that much?? Thanks for the input

 

i had some pretty scary bumpsteer before i completely replaced my suspension. one would hope illumina's and gf210's would do something about suspension stiffness, .................................................. ............................








right?

peace

 

What exactly is happening that you're calling it "bumpsteer"?


-Ted

 

+1 for Ted's question.

Also, what are your toe settings? If you're at zero toe or slightly toe out the car will have a tendency to pull on uneven road surfaces.

 

The toe is pretty close to stock spec as far as i know. I align the car 6 months ago although i replace the time after i did the alignment. Whats happening is when i go over an uneven section of the road the steering wheel would want to turn one direction hard unless i hold the steering wheel straight. Also when i am making a long turn i can feel the steering wheel jerk when one of the front wheels goes over a bump or a uneven section of the road.

 

this sounds more like tramlining.
http://www.tirerack.com/tires/tirete....jsp?techid=47

that sounds like bumpsteer, but i can't say whether its normal or not. i don't have much experience driving stock FCs.

 

That doesn't sound like bumpsteer at all.
All of that sounds normal.

As the tires hit uneven surfaces, it's going to deflect.
This causes the steering to get all crazy.


-Ted

 

I have driven a few other stock Fcs but they are equip with p/s so i don't know that would affect the steering feel.

Thanks for the input i will adjust my tire pressure first and see what else i can do.

 

Well i guess it could be normal after all but this is the only car i have driven that uneven roads would affect the car that much. I guess i would just have to drive another stock one on the same section of the road to confirm it. By the way would changing my alignment angles help reduce this? Example like adding more caster or reducing the toe? Thanks for the input.

 

I was just going to mention this...

Power steering systems "dampens" the backlash through the steering.
This is the same reason why manual steering has better road feel.

So everything you have described is normal.


-Ted

 

lol

 

Yes!