Why am i getting bump steer?
08-09-08, 10:48 AM
#1
Why am i getting bump steer?
I had this problem for some time. But now its really bothering me.
Went out for a relatively longer cruise than usual cause it was nice out (about 26 miles) just to get some gas and throw some mileage on. And this problem is really making me go nuts.
Whenever i encounter imperfections in the road, my steering wheel will jiggle and sometimes if one wheel will hit a bump, say the driver side front, the car will jiggle to the left. Like the car will actually move itself to left a bit.
At first when i noticed this a while back, i automatically assumed it was because my wheels werent balanced. Which is true, i had some fatter tires thrown on the rears just for that muscle car look (stock wheels btw).
When i got new wheels, they came full balanced and it cured the problem A LITTLE. Fast foward 4 months later it feels like the problem got worse or i really am starting to notice it because its always there.
At first upon initial use of new wheels, and the problem was still there but not much, i thought the wheel lugs werent tight enough.
I checked all 20 and they are within spec? 85ft lbs?
So now im leaning on my suspension, maybe toe links? I dont know squat about suspension so if someone can help me so i dont waste money for nothing, ill greatly appreciate it.
Here is my setup.
tokico adjustable strust all around (the white painted ones)
Springs = unknown (but car is dropped, 25.5 from ground to fender on driver and 26.5 on passenger. Yes its uneven, another problem i have to fix lol)
Wheels are 17x8.5 +40 with a 235/45/17 tire fronts..17x9.5 +38 with a 265/40/17 rear.
Wheels are brand new when i bought them, full balanced by tirerack.
Thanks in advance.
Went out for a relatively longer cruise than usual cause it was nice out (about 26 miles) just to get some gas and throw some mileage on. And this problem is really making me go nuts.
Whenever i encounter imperfections in the road, my steering wheel will jiggle and sometimes if one wheel will hit a bump, say the driver side front, the car will jiggle to the left. Like the car will actually move itself to left a bit.
At first when i noticed this a while back, i automatically assumed it was because my wheels werent balanced. Which is true, i had some fatter tires thrown on the rears just for that muscle car look (stock wheels btw).
When i got new wheels, they came full balanced and it cured the problem A LITTLE. Fast foward 4 months later it feels like the problem got worse or i really am starting to notice it because its always there.
At first upon initial use of new wheels, and the problem was still there but not much, i thought the wheel lugs werent tight enough.
I checked all 20 and they are within spec? 85ft lbs?
So now im leaning on my suspension, maybe toe links? I dont know squat about suspension so if someone can help me so i dont waste money for nothing, ill greatly appreciate it.
Here is my setup.
tokico adjustable strust all around (the white painted ones)
Springs = unknown (but car is dropped, 25.5 from ground to fender on driver and 26.5 on passenger. Yes its uneven, another problem i have to fix lol)
Wheels are 17x8.5 +40 with a 235/45/17 tire fronts..17x9.5 +38 with a 265/40/17 rear.
Wheels are brand new when i bought them, full balanced by tirerack.
Thanks in advance.
08-09-08, 02:10 PM
#2
Static camber setting (negative) will affect wander and weave on irregular road surfaces. So will toe (out), what is your alignment set at? Accelerated tire wear from either will really make the car unstable. Check if your tires are excessively worn out on the inside.
It looks like you were looking in the wrong places as wheel balance and torque (unless hand tight) will have little or no affect on wander and weave. Especially with the uneven ride height alignment is critical especially with how much negative camber gain FDs have under compression.
It looks like you were looking in the wrong places as wheel balance and torque (unless hand tight) will have little or no affect on wander and weave. Especially with the uneven ride height alignment is critical especially with how much negative camber gain FDs have under compression.
08-09-08, 05:15 PM
#3
I havent gotten an alignment since i bought the car so i dont know long its been since the car actually had one.
My assumption for alignment is if the car sways to either side, the alignment is off.
Which is the main reason why i didnt go for one, because the car does NOT do that.
Im just getting a hop for whenever i hit a bump.
But i have an update, i was fooling around with the adjustments of my front struts (probably a bad idea) and backed out each strut 2 full turns, or maybe 1.5 turns.
The car actually drives a bit better. Still get some jiggle on major bumps but not as bad.
Maybe my struts were set on very hard, maybe thats why it caused this problem?
My assumption for alignment is if the car sways to either side, the alignment is off.
Which is the main reason why i didnt go for one, because the car does NOT do that.
Im just getting a hop for whenever i hit a bump.
But i have an update, i was fooling around with the adjustments of my front struts (probably a bad idea) and backed out each strut 2 full turns, or maybe 1.5 turns.
The car actually drives a bit better. Still get some jiggle on major bumps but not as bad.
Maybe my struts were set on very hard, maybe thats why it caused this problem?
08-09-08, 05:46 PM
#4
Did you buy the car with the lowered ride height? If you didn't and lowered it without an alignment that would explain everything. If you know someone that works at a lube place and you can at least get it on the rack that would help a lot. It doesn't have to pull, if the toe is evenly out or the camber is evenly negative you will still have the problem you described. I don't know how shock setting would affect wandering so maybe someone else can chime in on that one.
btw your car has shocks not struts
FCs have struts. Two different suspension designs.
btw your car has shocks not struts
FCs have struts. Two different suspension designs.
08-09-08, 05:47 PM
#5
It could be from the struts being too stiff for the springs. That could cause the wheel that hits the bump to lose traction and unload a little. The other wheel still having grip could make to car do strange things. A blown strut can have a similar effect by letting the wheel bounce.
Wheel offset can do funny things too. I don't know what the stock offsets but if you end up with a really high scrub radius and unload one side with a bad/stiff strut it will also grab the wheel from your hands.
Wheel offset can do funny things too. I don't know what the stock offsets but if you end up with a really high scrub radius and unload one side with a bad/stiff strut it will also grab the wheel from your hands.
08-09-08, 11:03 PM
#6
Did you buy the car with the lowered ride height? If you didn't and lowered it without an alignment that would explain everything. If you know someone that works at a lube place and you can at least get it on the rack that would help a lot. It doesn't have to pull, if the toe is evenly out or the camber is evenly negative you will still have the problem you described. I don't know how shock setting would affect wandering so maybe someone else can chime in on that one.
btw your car has shocks not struts FCs have struts. Two different suspension designs.
btw your car has shocks not struts
FCs have struts. Two different suspension designs.Ultimately i want to do coilovers and a new set of wheels (dont really like my current wheels) before i do the alignment.
An alignment was something i wanted to do anyway, regardless of this problem or not, just because i never had it in my ownership (5 years).
Im gonna play with the "shock" setting a bit
, to see if i can tolerate the drive a bit more til i get the coilovers and new wheels. Then ill do the alignment right after.
It could be from the struts being too stiff for the springs. That could cause the wheel that hits the bump to lose traction and unload a little. The other wheel still having grip could make to car do strange things. A blown strut can have a similar effect by letting the wheel bounce.
Wheel offset can do funny things too. I don't know what the stock offsets but if you end up with a really high scrub radius and unload one side with a bad/stiff strut it will also grab the wheel from your hands.
Wheel offset can do funny things too. I don't know what the stock offsets but if you end up with a really high scrub radius and unload one side with a bad/stiff strut it will also grab the wheel from your hands.
08-11-08, 08:27 AM
#7
Racing Rotary Since 1983
iTrader: (6)
you have owned the car and haven't aligned it in FIVE YEARS?
here's your "to do" list.
1. since camber changes 1.5 degrees per inch of tire movement in compression it will do you no good to align the car until you get it at proper ride height.
remove the springs. identify the brand. inspect them. (perhaps you have the rear set on the driver's side.) inspect the upper spring rubbers. if the upper rubber mounts are o k and the springs were correctly situated use them as boat anchors and buy a set of Eibach Pro Kit springs. around $150 in the forum classifieds... you can always resell them later if you do coil overs.
2. now that you have the car sitting at equal right and left ride heights you may proceed to job one. alignment. for specs see the first post in my thread in this section... (Howard Coleman's FD chassis/suspension setup) do read the entire first post and don't forget tire pressures. take my alignment specs to the shop and tell them to align the car exactly to these specs and give you a printout. don't forget prior to aligning tire pressures need to be 30 fr and 27 rear.
once aligned, you car should track straight as an arrow.
wheel balance & wheel lug nut torque (70 ft pounds) are not factors as to bump steer. any different lateral wheel offset will slightly increase "hunting" or darty-ness as the scrub radius will increase.
KhanArtisT and jgrewe are on the money. too stiff shocks cause a loss of traction and the ride height thing is a big deal...
and lastly the FD has no struts. it has shock and springs. Buicks have struts.
good luck, it should be easy to straighten out.
howard
here's your "to do" list.
1. since camber changes 1.5 degrees per inch of tire movement in compression it will do you no good to align the car until you get it at proper ride height.
remove the springs. identify the brand. inspect them. (perhaps you have the rear set on the driver's side.) inspect the upper spring rubbers. if the upper rubber mounts are o k and the springs were correctly situated use them as boat anchors and buy a set of Eibach Pro Kit springs. around $150 in the forum classifieds... you can always resell them later if you do coil overs.
2. now that you have the car sitting at equal right and left ride heights you may proceed to job one. alignment. for specs see the first post in my thread in this section... (Howard Coleman's FD chassis/suspension setup) do read the entire first post and don't forget tire pressures. take my alignment specs to the shop and tell them to align the car exactly to these specs and give you a printout. don't forget prior to aligning tire pressures need to be 30 fr and 27 rear.
once aligned, you car should track straight as an arrow.
wheel balance & wheel lug nut torque (70 ft pounds) are not factors as to bump steer. any different lateral wheel offset will slightly increase "hunting" or darty-ness as the scrub radius will increase.
KhanArtisT and jgrewe are on the money. too stiff shocks cause a loss of traction and the ride height thing is a big deal...
and lastly the FD has no struts. it has shock and springs. Buicks have struts.
good luck, it should be easy to straighten out.
howard
Last edited by Howard Coleman; 08-11-08 at 03:08 PM.
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08-11-08, 07:52 PM
#9
Thanks for the advice howard.
Yes i know it was dumb of me to not align the car.
It was just something that wasnt of priority for me at the time then so i always put it off.
Now i see why its important.
Any reason why those tire pressures should be where you stated? And is that the final reading it should stay?
Cause my new wheels i got, came with a pressure of 35 on all 4, which is where it still is now.
Should i go out there and correct that AT LEAST?
Yes i know it was dumb of me to not align the car.
It was just something that wasnt of priority for me at the time then so i always put it off.
Now i see why its important.
Any reason why those tire pressures should be where you stated? And is that the final reading it should stay?
Cause my new wheels i got, came with a pressure of 35 on all 4, which is where it still is now.
Should i go out there and correct that AT LEAST?
