Suspension and Chassis Questions about your suspension? Need chassis advice?

Alignment experts - advice sought

Old 06-10-2019, 12:09 PM
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Alignment experts - advice sought

After replacement of old, stock parts with new stock LCAs, steering linkages, and an alignment, my steering definitely feels tighter, but two things are strange - the return to center seems to drag more (it doesn't float right back to center, it drags) and the car hops and grinds the treads on sharper turns like parking lots. It did not do either of these before.

Conditions:

Before LCA's, linkages, and alignment:
Steering on center - loose, boaty, play
Steering return to center normal (fast)
Slow, sharp, turns - no grinding or hopping- smooth
LCA bushings old, ball joins old, etc
Tires new
Struts, strut mounts new
Wheel bearings new
rotors, calipers, pads new

After:
Steering on center better, handling solid
Steering return to center lags, sometimes does not return fully when steering wheel is let go. Slow to return to center. Sometimes have to steer it a little out of turn.
Slow, sharp turns: significant tread grind and hopping/slipping when in the turn

Thought:
The only thing that really changed was the toe. I wonder if that alone could do this sort of stuff? Or maybe I messed up on converting 3/32" total toe to .2 degrees total toe?

Specs Below (alignment set to "Street Specs" from other thread (pic at very bottom):



Last edited by Tootie Pang; 06-10-2019 at 03:52 PM.
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Old 06-10-2019, 01:31 PM
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Re: Alignment experts - advice sought

Just finished my front end replacement and while alignment is pending, it feels like the new ball joints and tie rod ends need to loosen up a bit. Wear in.

Ill watch this thread for experienced answers. Which mine is not.
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Old 06-10-2019, 02:14 PM
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Re: Alignment experts - advice sought

Caster affects the return to center...
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Old 06-10-2019, 05:14 PM
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Re: Alignment experts - advice sought

I'm using the "hard street" alignment on a 92 that I Autocross.
My setup is basically 100% rebuilt suspension+steering.
Toe in should be 0.05 degrees.

I also get a slight clunk/roughness at low speed full lock turns, but nowhere else.
I honestly think that's normal.
But tire rubbing with a 245 or smaller tire means something went wrong.
My steering doesnt return to center because I have a very tight New RedHead box.
If u box is stock, it should easily return to center.
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Old 06-10-2019, 05:16 PM
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Re: Alignment experts - advice sought

These are stock size 245/50R16 BFG Comp 2. It's not tire rubbing (at least I'm pretty sure), it's the tracking in slow, tight turns- hop hop hop

McLovin, is that 0.05 deg of total toe in or per side?

I think I found an error. For the street specs I attached, Total toe is supposed to be 3/32" which means 3/64" (0.046875) per wheel. At 25.7" diameter (12.85" radius), I used the calculator below.

The toe in per wheel should be 0.2 deg and 0.4 deg total. I am set at 0.2 total, about half of what the street settings say.

But, despite that, McLovin, you are recommending LESS than that at 0.05 deg (total or per side).

Service manual specs are Camber 0.3, Caster 4.7, Toe 0.0. Maybe I have too much toe in?

Could this make that much difference?


Last edited by Tootie Pang; 06-10-2019 at 05:38 PM.
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Old 06-10-2019, 06:35 PM
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Re: Alignment experts - advice sought

Ok, no tire rubbing means nothing is completely wrong as I have the same tire (the a/s) on my 92.

3/32 should be 0.05 degree toe in on each side.
I can go 90mph+ and it tracks perfectly straight.
Although 0.1 isn't a deal breaker for a street car.

I remember talking to an old GM engineer here that said 3rd gens had garbage factory alignments due to customers complaining about low speed turning.
I think this low speed "clunk/hopp" is what they were talking about.
I honestly think it's just a quirk of our cars
If both our cars do the same thing, it's probably normal.
I've been hammering on my 92 at the AutoX and it hasn't done anything weird steering wise.
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Old 06-10-2019, 06:43 PM
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Re: Alignment experts - advice sought

Originally Posted by Saxondale View Post
Just finished my front end replacement and while alignment is pending, it feels like the new ball joints and tie rod ends need to loosen up a bit. Wear in.
I installed all this stuff on mine.

No adjustment for caster is allowed on our cars with factory control arms.

I set camber by using a yardstick as a straight-edge, and holding a bubble-level against the yardstick.

I set toe in at 1/16".
This was done by using a tape-measure, and measuring from a reference point on the trailing edge of the front tires, and comparing to the leading edge of the front tires. Front number 1/16" less than the rear number. Tracks straight as an arrow when WOT in 5th gear on the interstate. That's good enough for me.

Handling felt WAY DIFFERENT after I got it all together. And thank goodness for that, because everything in the front end was completely worn out. With the new parts, everything was much tighter. Maybe a little "notchy" feeling when going lock-to-lock. I've driven it about a thousand miles since I did all the work. I'd say it feels a little more "broken-in" now than when the work was just completed.

I still have a little slop in the steering because of the factory steering gear and steering shaft. Otherwise, steering is very positive and predictable these days. "Return-to-center" is very normal-seeming.

Its not a race car. Max speed is probably around 110 if I could find a flat place without traffic where could just hold it on on the floor and let the speed build. It runs up to 90 without too much drama. Anything after that is slow to come, and the whole ride feels pretty sketch because of all the other noises the car makes.
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Old 06-11-2019, 10:04 AM
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Re: Alignment experts - advice sought

I wanna know how the rear toe changed before/after


Originally Posted by W.E.G. View Post
No adjustment for caster is allowed on our cars with factory control arms.
Yes there is, not sure where you're getting that from. It's got a limited range, but it's adjustable
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Old 06-11-2019, 10:23 AM
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Re: Alignment experts - advice sought

I think the molecules shifted.

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Old 06-11-2019, 04:51 PM
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Re: Alignment experts - advice sought

[QUOTE=scooter;6307656]I wanna know how the rear toe changed before/after

Probably bad wheel bearings.
Mine did the same on one side.
The same side that has a small bearing leak.
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Old 06-11-2019, 05:22 PM
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Re: Alignment experts - advice sought

Nah. It's fine. Those are hundredths of degrees, not tenths- which would be a big deal. I have a rebuilt rear axle.
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Old 06-15-2019, 01:24 PM
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Re: Alignment experts - advice sought

What you describe is a factory inherent defect in the cars since when new. The steering geometry has a poor Ackermann design. What this translates to is the car looses toes when turned to full lock- a better world would be to gain toe. At 12* turn (full lock is close to 35* and much worse) the inside tire should 12.5* when the the distance between front wheel centerlines is considered. We only get dynamic 12 and 12 which does not have Ackermann (Ackermann is the proper gain in inside wheel angle compared to outside wheel angle paths of direction in a circle.) Becuase of this the car equates to a "dynamic toe in" condition which makes the front of the car lift the chassis (we refer to this as "climb"). It can only climb so much before the weight of the car and slip of the tire contact patch relies itself and then repeats.

When your car had older worn parts such as the old strut mounts, this allowed for flex and decreased this feel. Putting new parts back in makes it come to notice as you turn to full lock in tight parkinglot maneuvers.
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Old 06-16-2019, 09:48 AM
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Re: Alignment experts - advice sought

Informative as always Dean. Thanks for the insights.
What do you make of that chart in the first post? (I've copied and pasted it below and you've probably answered that question before)

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Old 06-16-2019, 06:33 PM
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Re: Alignment experts - advice sought

I have the same issue with turning on tight turns....I have wondered if it's cause I have the incorrect idler arm with 2+ inch drop versus the correct factory drop.....

My 85 handled better than my 92 with upgraded parts....go figure....that idler arm....hmmmm....
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Old 06-17-2019, 11:50 AM
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Re: Alignment experts - advice sought

So I discovered I miscalculated the total toe and had double the 3/32 total toe. I backed each tie rod adjuster off about 1-1/2 turns and the car feels way better. Still fine tuning it.

For that relay rod and idler arm, my new one was the same geometry as the old one so I simply marked the bolt locations. That method seems to have gotten it close and everything looks pretty even when I eyeball it going back and forth.
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Old 06-17-2019, 12:06 PM
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Re: Alignment experts - advice sought

1.5 turns each side sounds like a lot. Did you measure the toe afterwards? It's easy enough to do with a straight edge and two tape measures
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Old 06-17-2019, 07:09 PM
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Re: Alignment experts - advice sought

Toe-in should be around 0.05 INCHES on each side, not DEGREES. Major difference. 2 .05" = .100"; 3/32" total = .09375". Pretty much the same thing.

That chart Skinny posted is very similar to what I've found to work well; my recommendations are close to the "hard street" setting, with slightly less toe-in. I like .030" or 1/32" each side. Also you may want some amount of caster and/or camber split, depending on how high the road crowns are in your area on the roads you use the most. (as much as about more of each on the left) The more caster you crank in, the more noticeable the effect of the crown. But you won't go far wrong using that chart as a starting point.

Note however, that to add positive caster, the top of the strut moves REARWARDS; which makes the wheel tend to rub the fender just in front of the door. Can't be helped. You just have to learn to drive around the tendency. Which is greatest when the wheel is in a "rebound" situation, i.e. when the body is lifted up off of the wheel, compared to normal static sitting level. Going out of driveways is a typical situation that makes it happen.

Dean's description of the "hopping" sort of action in tight low-speed turns is spot on. It's another of those minor nuisances that just can't really be helped, without MAJOR surgery and changes. The idler arm is irrelevant to that.

I agree, 1 turns on the adjusters sounds like ALOT of change. turn is significant. turn is probably close to .100" on each side.

Last edited by sofakingdom; 06-17-2019 at 07:14 PM.
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Old Yesterday, 03:45 PM
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Re: Alignment experts - advice sought

OK, if you want to say caster is "adjustable" on these cars by whatever minute fore-and-aft gap there is between the slots in the strut-mounts and the studs on the base plates, and/or the gap between the fender-holes and the studs for the strut-mount base plates I'll agree to that much.

An infinitessimally-small amout of fore-aft caster-play is indeed present. So, I amend my remark: Caster is not meaningfully adjustable on these cars.

As compared to the significant adjustment (long slots) available for camber.

Maybe y'all have different strut mounts. This is what the factory-pattern mount looks like on my 1988 Sport Coupe. Plenty of camber adjustment. Essentially ZERO caster adjustment.

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Old Yesterday, 03:55 PM
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Re: Alignment experts - advice sought

Unless I'm overlooking something, this is how much you've got to work with for caster.

You can see that the long groove in the strut mount is slightly wider than the stud that the mount rides on. You've got that much "adjustment" available for caster.


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Old Yesterday, 04:25 PM
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Re: Alignment experts - advice sought

My car was toeing in pretty hard. I did about 1-1/2 turns on each adjuster to bring the toe out. Thanks for the tips. FWIW, it does not hop during hard turns now that I backed the toe out a bit. I'll keep messing.
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Old Yesterday, 05:23 PM
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Re: Alignment experts - advice sought

Originally Posted by W.E.G. View Post
OK, if you want to say caster is "adjustable" on these cars by whatever minute fore-and-aft gap there is between the slots in the strut-mounts and the studs on the base plates, and/or the gap between the fender-holes and the studs for the strut-mount base plates I'll agree to that much.

An infinitessimally-small amout of fore-aft caster-play is indeed present. So, I amend my remark: Caster is not meaningfully adjustable on these cars.

As compared to the significant adjustment (long slots) available for camber.

Maybe y'all have different strut mounts. This is what the factory-pattern mount looks like on my 1988 Sport Coupe. Plenty of camber adjustment. Essentially ZERO caster adjustment.
The castor slot is in the body UNDER the mount plate. It's not "infinitesimally small". You should probably look at the cars a little more before you start posting things like they are facts.

I don't know the range in degrees, but the slots have about 1" of adjustment. As I said, it is adjustable and it is limited.
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Old Yesterday, 05:54 PM
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Re: Alignment experts - advice sought

Right: the CAMBER adjustment is the slots in the strut mount; CASTER adjustment is slots in the strut tower itself. Makes an "x-y" sort of pattern.

There's enough slot length to move the caster from the factory's stupid-a$$ setting of 1 or whatever it is, to at least 4 in every one of these cars I've ever seen. Most of em will go closer to 5. If you're not happy with whatever you've got, it's a piece o cake to lengthen the slots.
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Old Yesterday, 06:08 PM
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Re: Alignment experts - advice sought

OK. I see now the relationship that allows the caster adjustment. That's actually a goodly amount of range for caster. Thanks for the pic!
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Old Yesterday, 06:39 PM
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Re: Alignment experts - advice sought

While I've got all y'all smart fellers setting me right on this business of caster, tell me if my shade-tree method of calculating my caster-value with my iPhone is correct.

If I understand correctly, I can turn the wheels from full-lock in each direction, and using some sort of straight-edge against the edge of the wheel, I use my angle/protractor app on the phone to take the measurement of the CAMBER at each full-lock position. Then I subtract the lesser camber-value from the higher camber-value, and that will give me my CASTER value.

For instance, one lock-position shows a camber of 89 degrees and the opposite lock-position shows a camber of 86 degrees. The difference of the values being three degrees. Therefore, I'm running three degrees caster. Does that sound right?
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