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Discussion Starter · #1 ·
I had my front end aligned after I replaced all with complete PST polygraphite kit and Moog springs, now I have oversteer that makes for a white knuckle ride on the freeway if you make a quick lane change,, it wants to come around on me, what gives?? I had a performance shop do the alignment.
:confused:
 

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Did you get a printout sheet of the specs?Without seeing that its kind of hard to tell what they did.I have always had good luck with the old school alignment shops.
 

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Is it possible the springs have settled since the alignment? It could upset the alignment results.
 

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I agree, without seeing what specs the alignment was set to it's hard to address whats wrong.
 

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do you have a giant rear ARB?

also check the rear to see if you have toe out, and make sure the tires are the same on all four wheels
 

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Discussion Starter · #6 ·
do you have a giant rear ARB?

also check the rear to see if you have toe out, and make sure the tires are the same on all four wheels
Wish I had gotten the specs from the alignment. I do have the same tires/wheels on all corners. I haven't rebuilt the back suspension yet, not too bad but is worn. The aligner (is that a word?) did say he puts as much negative camber as possible in old A bodies. Sorry, I guess i'm dumb to the term,, what is a "giant rear ARB"?
 

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An alignment should not be drastic enough to change your car into losing the back end on a free way, to me it sounds like there is more going on. If you go from worn out parts to some brand new poly stuff + aggressive alignment the car could just be reacting more than you expect to your normal driving causing an unsettling feeling. We aren't talking about road racing where understeer/oversteer will inherently show up at the limit, we are talking about cruising around on the roads.
 

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Wish I had gotten the specs from the alignment. I do have the same tires/wheels on all corners. I haven't rebuilt the back suspension yet, not too bad but is worn. The aligner (is that a word?) did say he puts as much negative camber as possible in old A bodies. Sorry, I guess i'm dumb to the term,, what is a "giant rear ARB"?
anti-roll bar. SImply, a big front bar will cause understeer and a big rear bar will cause oversteer. For example, my Honda in stock form with a 17mm front bar and no rear bar will understeer like a pig, which is why it has the biggest rear bar available (23mm) to shift the bias more to the rear.

Some resting negative camber is good, especially in 60s GM cars, which have a tendency to go positive as the suspension compresses, but too much will cause tire wear.

I would check the toe of the rear, that may be where your problem is, and the out of whack front was covering for it.
 

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An alignment should not be drastic enough to change your car into losing the back end on a free way, to me it sounds like there is more going on. If you go from worn out parts to some brand new poly stuff + aggressive alignment the car could just be reacting more than you expect to your normal driving causing an unsettling feeling. We aren't talking about road racing where understeer/oversteer will inherently show up at the limit, we are talking about cruising around on the roads.
I went from a standard alignment on the Honda to an autocross alignment - 0 camber, 0 caster, 0 toe to 2° neg camber, about 2° positive caster, 3/16 toe OUT on the front and about 1° neg camber and 1/16 toe IN in the back. Going around turns on the way there was a little unnerving until I got use to it. It felt like it had 4 wheel steering.
 

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Personally I would take it back,ask for a spec sheet and make the alignment guy go with you for a road test and have him drive it with you riding shotgun.Have him drive the same way that you did to repeat the problem.Its a street car not a road racer,it should be aligned to factory specs IMO.Im not a front end guy but but replacing worn parts and having an alignment done should improve things not make it worse.Did the guy forget to tighten the tie rod ends or upper A arms?This could have caused lost shims and adjustment,doubtful but possible.It sounds to me like it has too much caster and camber which will cause your issue.Take it back,they did something wrong IMO
 

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I thought a lot of positive caster is good for these cars? Ive been reading posts where people are saying to put as much positive caster in it as you can. Ive been meaning to have my roommate who owns an alignment shop do it for me to test it out.
 

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I thought a lot of positive caster is good for these cars? Ive been reading posts where people are saying to put as much positive caster in it as you can. Ive been meaning to have my roommate who owns an alignment shop do it for me to test it out.
It's a band aid for the real problem, which is terrible suspension geometry. It helps, but doesn't fix the problem, and introduces the additional problem of tire wear.
 

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Personally I would take it back,ask for a spec sheet and make the alignment guy go with you for a road test and have him drive it with you riding shotgun.Have him drive the same way that you did to repeat the problem.Its a street car not a road racer,it should be aligned to factory specs IMO.Im not a front end guy but but replacing worn parts and having an alignment done should improve things not make it worse.Did the guy forget to tighten the tie rod ends or upper A arms?This could have caused lost shims and adjustment,doubtful but possible.It sounds to me like it has too much caster and camber which will cause your issue.Take it back,they did something wrong IMO
Just thinking about this, it's possible the increased neg camber in the front is resulting in additional grip in a quick maneuver, which would have the tendency to either reduce understeer or increase oversteer, or induce oversteer in instances where a car was neutral.

I'm not sure if this is true for the a-body cars, but I know that increased caster in the Honda results in negative camber on the outside wheel in a turn.
 

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I went from a standard alignment on the Honda to an autocross alignment - 0 camber, 0 caster, 0 toe to 2° neg camber, about 2° positive caster, 3/16 toe OUT on the front and about 1° neg camber and 1/16 toe IN in the back. Going around turns on the way there was a little unnerving until I got use to it. It felt like it had 4 wheel steering.
That's in a racing environment when pushing the cars handling attributes to the limit. Not the same as doing some lane changes on a freeway under part throttle. Also in regards to the later post, if the alignment netted more front end grip it would again never be factored in on the freeway.

If the shop really got the toe specs wrong, that could cause some problems. I would want to make sure that they didn't tighten something all the way and something is mechanically shifting around under lateral loads.
 

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+caster will make the car drive better ( imho.) I had 2+ and then went to 4.5+ its much better now.
Think of a shopping cart when the wheel is bent or back- The cart wobbles bad,but when new, your wife can push all over the store till your Money run out!!!! This is over simplified but you get the picture. Also what upper control arm do you have now?
 

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Squirrely-handling on the street after an alignment?

My guess is that they screwed-up the toe.
 

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That's in a racing environment when pushing the cars handling attributes to the limit. Not the same as doing some lane changes on a freeway under part throttle. Also in regards to the later post, if the alignment netted more front end grip it would again never be factored in on the freeway.

If the shop really got the toe specs wrong, that could cause some problems. I would want to make sure that they didn't tighten something all the way and something is mechanically shifting around under lateral loads.
I was referring to how the alignment changes affected the car on the way to the event, so in normal driving, not just racing. In addition to the front being darty due to the toe out, the back felt much looser.

As for the front end grip, the OP mentioned getting oversteer during a "quick lane change". If it's "quick" enough to shift weight, it could be quick enough to break the back end loose, especially if the rear now has less grip relative to the front than it did previously. That seems less likely than other possible causes though.

Maybe Derek69SS will stop in on this thread. He's another Self Appointed Internet Expert :D
 

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Checking the toe at home with a tape measure will tell you where it's set at, (approximately).
 

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Take it back to the shop and tell them it drives like caca. Negative caster is not what you want, you want as much positive as you can get and still keep camber within spec.
 

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I was referring to how the alignment changes affected the car on the way to the event, so in normal driving, not just racing. In addition to the front being darty due to the toe out, the back felt much looser.

As for the front end grip, the OP mentioned getting oversteer during a "quick lane change". If it's "quick" enough to shift weight, it could be quick enough to break the back end loose, especially if the rear now has less grip relative to the front than it did previously. That seems less likely than other possible causes though.

Maybe Derek69SS will stop in on this thread. He's another Self Appointed Internet Expert :D
I can completely understand a darty feeling to your toe specs on a short wheelbase car. Makes sense for sure. Perhaps when I see someone say "oversteer", I naturally think of the back end sliding about. It would not surprise me if the OP has a darty car, rather than actually oversteering. As mentioned it would its very unlikely a simple alignment causes the back end to step out on free way lane changes, even if they were "quick" (unless he's Fast and Furious driving at 100 mph). If I were the OP, I would look at the toe specs, and ensure nothing is mechanically wrong. Otherwise he may need to get used to the new characteristics of the car, just as you did with your Honda.
 
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