Positive Camber Impossible?

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gdizzle

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On my 66 dart, redid front end, did not use the Offset bushings, and the alignment guys say it is impossible to get positive Camber. Searching the interweb, people are saying the original bushings were never able to do positive camber. I guess because they were using Bias radials?

Any confirmation on this? I am still needing the car to stay straight and give me a little wheel return when I do a turn. Right now there is NO return and the car wont return to straight.
 
On my 66 dart, redid front end, did not use the Offset bushings, and the alignment guys say it is impossible to get positive Camber. Searching the interweb, people are saying the original bushings were never able to do positive camber. I guess because they were using Bias radials?

Any confirmation on this? I am still needing the car to stay straight and give me a little wheel return when I do a turn. Right now there is NO return and the car wont return to straight.
I just redid my 65 Dart and I did use the offset bushings in the front and rear of the UCA. Not much better. I think the only thing left to do is buy some after market control arms that are adjustable.
easyrider
 
I think you are meaning caster, not camber. It's very easy to get positive camber on these cars, unless something is bent.
 
I think you are meaning caster, not camber. It's very easy to get positive camber on these cars, unless something is bent.

Yeah some of us with manual boxes do not want all the positive caster, to hard to steer!! Camber has never been an issue!
 
Need to check condition of strut rod bushings. They dictate lower control arm position which is half of the caster equation
 
I've never had a problem getting a degree or two of positive caster with stock bushings...
 
I assume like the others you're actually talking about positive caster? Because you don't want positive camber anyway, unless you actually are running bias ply's. But be careful about your "alignment guys", if they're using the factory specs (which are for bias plys!) they will be trying to give you positive camber. Which you don't want.

Remember too that the ride height of the car alters the suspension geometry. So, just because one car can get a couple of degrees of positive caster with stock bushings doesn't mean yours can if it's not sitting at the same height.

And if you are running radials, you should be looking for -.5* camber, +3 caster (or more if you have power steering and can get more), and 1/16 to 1/8 toe in. Manual steering should still have positive caster, the more you have the more stable the car will be at speed. It can increase the steering effort some, but it's not a huge effect.
 
i have always been able to get enough positive caster as well.Maybe as suggested you have the front too high,this will kick your upper A arms forward taking away caster.
for those that find manual steering difficult don't dry crank..wait 'til you are moving.Manual steering should never be difficult in a small block A body
 
For those that find manual steering difficult don't dry crank..wait 'til you are moving.Manual steering should never be difficult in a small block A body

Hardest thing to drive into my wifes head!! Get it moving first! When she learns this she will likely drive it more. The FB's are great grocery cars! But put +3 in a manual steered car and most anyone would hate it. I have mine at about -1 and it drives just fine for me!
 
Turning the wheels with the vehicle sitting still is never a good idea. You just notice it more with manual steering. The forces felt by the steering linkage is the same. Front ends (and tires) last longer if you let the vehicle creep a little as you turn.
 
Remember too that the ride height of the car alters the suspension geometry. So, just because one car can get a couple of degrees of positive caster with stock bushings doesn't mean yours can if it's not sitting at the same height.

This is VERY important if the OP's tires are smaller than the original bias plys - and if those are 13" rims I see, they probably are.

This wouldn't matter if we had non-adjustable coil springs on our cars, but the adjustable torsion bars give the alignment jockeys yet another thing to fool with that they generally get wrong. With the smaller tires, they'll likely adjust the ride height too high, assuming the stock ride height given in the manual (which measures the inner LCA pivot at the K frame to the ground - which applies only when the tire sidewall is the same as what the factory expected).

Now you've got the LCA's jacked downwards an inch or two more than they should be - the inch or two lost with the smaller 13" P185/70 (or P175/70) radials available today. That inch or two is mirrored by the UCA's, which also move the upper ball joint forward as they pivot down, which moves the spindle/kingpin forward to match. That eats up whatever caster you had to work with in the first place.

23mlor8.jpg


And between the reduction in caster and the smaller tire, you get less trail. The result is a twitchy front end that'll hunt lanes with the slightest twitch at the wheel, and won't center itself when you make a tight turn.

176163d1110144907-tire-size-vs-caster-kingpin.jpg


-Kurt
 
This is VERY important if the OP's tires are smaller than the original bias plys - and if those are 13" rims I see, they probably are.

This wouldn't matter if we had non-adjustable coil springs on our cars, but the adjustable torsion bars give the alignment jockeys yet another thing to fool with that they generally get wrong. With the smaller tires, they'll likely adjust the ride height too high, assuming the stock ride height given in the manual (which measures the inner LCA pivot at the K frame to the ground - which applies only when the tire sidewall is the same as what the factory expected).

Now you've got the LCA's jacked downwards an inch or two more than they should be - the inch or two lost with the smaller 13" P185/70 (or P175/70) radials available today. That inch or two is mirrored by the UCA's, which also move the upper ball joint forward as they pivot down, which moves the spindle/kingpin forward to match. That eats up whatever caster you had to work with in the first place.

23mlor8.jpg


And between the reduction in caster and the smaller tire, you get less trail. The result is a twitchy front end that'll hunt lanes with the slightest twitch at the wheel, and won't center itself when you make a tight turn.

176163d1110144907-tire-size-vs-caster-kingpin.jpg


-Kurt

The problem with this analysis is that the factory ride height is not set from a single point. It's actually set using the difference between the height at the LCA pivot adjusting blade and the lowest height at the steering arm (bottom of the lower ball joint). What does that mean? It means the factory procedure actually sets the angle of the LCA, not the ground clearance. Which means tire height is totally irrelevant to using the factory specifications. The distance from the ground is literally removed from the equation, and only the angle of the LCA is counted. So, even assuming that the 13" rims aren't using a higher profile tire that's actually the same height as a larger diameter rim with a smaller profile tire, if the factory procedure is used the LCA will end up exactly where the factory intended it to be. Now, that won't be where the car will handle best if radials are being used instead of bias ply's, but that's a whole different discussion.

Factory procedure
factoryalignspecs.jpg
 
The distance from the ground is literally removed from the equation, and only the angle of the LCA is counted.

I stand corrected. And now that I think of it, I saw that same page from the service manual when I first looked up the procedure.

Now I have to figure out where my memory of "ground clearance to LCA" came from, because it's sticking in my mind hard enough to have come from somewhere else - not my own brain fart. Might be part of the procedure listed in the alignment tool's computer at the tire shop. Still worth being careful though, before someone starts cranking on the torsion bar adjustment bolts as if there's no tomorrow.

I do take issue with the factory suggestion of "jouncing" the car though. Doesn't work. Rolling it back and forth does better to settle the suspension where it'll be normally, though if toe in is wrong, this may cause the suspension to squat or stand high. It'll be obvious as the tires deflect though; someone who knows what they're doing should figure it out.

-Kurt
 
Oh it's definitely worth being careful. Most of the techs at alignment shops nowadays have no idea how to deal with one of these cars. Having them follow the factory procedure correctly would be outstanding, even if it would result in the wrong alignment for radials. But most places you won't even get that. That's why I bought all the tools to do my own alignments. Well, that and the fact that most shops won't put a "custom" alignment on a car, even after you explain to them that using the factory numbers "in the computer" will result in a poorly handling car because the factory specs are for bias plys and are completely the opposite of what radials should have.

And yeah, "jouncing" doesn't work, the car has to roll to settle things out.
 
Well all that is not to say that Chrysler did NOT use the "to the ground" measurement, because they certainly did. Just not where ride height is concerned.
 
...but i think guys crank the front up to where they like to see it...and that can
can mess up caster......
 
...but i think guys crank the front up to where they like to see it...and that can
can mess up caster......

Raising one from the front has no effect on caster, but it will change camber. Raising or lowering the rear will affect caster, though.
 
if you raise the ride height of the front end the upper ball joint will move down and forward.
 
if you raise the ride height of the front end the upper ball joint will move down and forward.

Not enough to have an appreciable effect on caster. You're talking less than .5 degrees. I've done it.
 
Great info guys. Still unsure if i am able to get my steering to return. I believe this means positive Caster (not camber as I mistakenly posted originally). So how can I get positive Caster? Is it possible? I have now replaced everything, and still the steering is loose. and no return after a turn. I want it to force its way back to the center, and keep that line until I steer. Possible? I am running 14in tires.
 
Not enough to have an appreciable effect on caster. You're talking less than .5 degrees. I've done it.

RRR, perhaps you can give me the scientific explanation for this then: I'm running eccentric UCA's on my Valiant (installed correctly, NOT per the Moog instructions). It has P185/70/R13s on it, and with the LCA's jacked up too high by the alignment shop, they were able to get about 1.5 degrees of caster dialed into it, with about .5 negative camber. Like this, the car acted squirrlier than a Chip and Dale cartoon. Also pulls a bit to the right.

With P215/75/R14's on the front - without adjusting a single thing from the above - you could practically drive hands off. It would track dead center and turning left or right would result in the steering wheel coming back to center perfectly. Granted, the back of the car was now about 2" lower than previously, as the 13's were still in the back.

Since the 14's were only a test (those P215's were running on dangerously narrow 4.5" SBP rims), I put the original 13" wheels back on with the P185's, then dropped the LCA's down 2" since. It's still uncomfortable and pulls to the right a bit, but it's more controllable and predictable. I also get a bit more self-centering through tight turns, but not enough.

Perhaps a trail issue rather than than caster? Either way, I'm rather convinced the tire diameter is amplifying (or decreasing) some element of the suspension geometry, but I'm not going to rest until I know the exact science behind what's going on.

My bet is that more than a few of us may have a base-model A-body on factory 13's that would make for nice daily drivers/beaters as-is, but do not necessarily justify SBP 14" wheel swaps.

-Kurt
 
Great info guys. Still unsure if i am able to get my steering to return. I believe this means positive Caster (not camber as I mistakenly posted originally). So how can I get positive Caster? Is it possible? I have now replaced everything, and still the steering is loose. and no return after a turn. I want it to force its way back to the center, and keep that line until I steer. Possible? I am running 14in tires.

You really haven't posted enough information for a proper diagnosis. We don't know what your current alignment specs are, what size tires you're running other than that they're on 14" rims and based on your comments they're probably radials, what your ride height is, torsion bars, shocks, what's new, etc. Even with stock design bushings the car should be able to achieve positive caster. Not a lot, but +1.5* caster with the stock bushings shouldn't be impossible. More is better, but that usually takes Moog 7103 offset UCA bushings.

But, I don't think that's the problem you're having. If the steering will not return to center after a turn that's much more likely to be a problem with the steering box. Even with slightly negative caster the steering should return to center after a turn. Do you have manual or power steering? Has the steering box been rebuilt? Anything in the steering linkage changed with the rebuild?

RRR, perhaps you can give me the scientific explanation for this then: I'm running eccentric UCA's on my Valiant (installed correctly, NOT per the Moog instructions). It has P185/70/R13s on it, and with the LCA's jacked up too high by the alignment shop, they were able to get about 1.5 degrees of caster dialed into it, with about .5 negative camber. Like this, the car acted squirrlier than a Chip and Dale cartoon. Also pulls a bit to the right.

With P215/75/R14's on the front - without adjusting a single thing from the above - you could practically drive hands off. It would track dead center and turning left or right would result in the steering wheel coming back to center perfectly. Granted, the back of the car was now about 2" lower than previously, as the 13's were still in the back.

Since the 14's were only a test (those P215's were running on dangerously narrow 4.5" SBP rims), I put the original 13" wheels back on with the P185's, then dropped the LCA's down 2" since. It's still uncomfortable and pulls to the right a bit, but it's more controllable and predictable. I also get a bit more self-centering through tight turns, but not enough.

Perhaps a trail issue rather than than caster? Either way, I'm rather convinced the tire diameter is amplifying (or decreasing) some element of the suspension geometry, but I'm not going to rest until I know the exact science behind what's going on.

My bet is that more than a few of us may have a base-model A-body on factory 13's that would make for nice daily drivers/beaters as-is, but do not necessarily justify SBP 14" wheel swaps.

-Kurt

Every time you change the ride height of the front of the car with respect to the rear of the car the caster changes. In your case, if you lower the back of the car with respect to the front, you've added positive caster. Caster is just the tilt on the spindle. Positive caster means the top of the spindle is leaned toward the back of the car. So lowering the back of the car adds positive caster (assuming nothing else changed).

A 215/75/14 is 26.7" tall. A 185/70/13 is 23.2" tall. If your +1.5* of caster was with 185/70/13's all the way around, and you then added the 215/75/14's to the front only, you added a VERY significant amount of positive caster. It's not 1.5* anymore with that set up, regardless of you not changing your alignment. That's a 1.75" rubber rake to the back. Instant positive caster. Nothing in the front suspension changed, so, the camber, toe, everything else is the same. But the caster changed because the angle of the spindle changed with the rear drop.

When you lowered the front you changed all of your alignment specs. Everything. Caster, camber, toe, all of it. If you just consider the drop in ride height in the front compared to the rear you should have lost caster, but, because the suspension geometry itself changed the caster change isn't just based on the change in rake. You probably made some of the numbers better, which is why the handling feels better. But any significant change in ride height with the front adjusters requires a new alignment.

And then there's the pulling to the right. This could be a ton of things too, most of them mean your alignment shop isn't great. It could mean that they actually set the alignment specs exactly the same on both sides, which would cause the car to track slightly to the right since most roads have some crown to them. Typically, cars are actually set up so they're specs aren't the same left and right, they dial in a little pull to the left to counter the effect of road crowning. Racers of all kinds don't like this and set their alignments up the same side to side, but out on the public streets that means they tend to pull a little to the right because of road crown. Or it could just mean your alignment was never right to begin with.
 
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