A-Arms...Early vs. Late

[Hard Luck]

I know that the geometry changed in the SquareBodies and it may be that they changed a few times, and I heard that there may even be an improved turning radius on some of the trucks including the Suburban.

What I am wondering is where did the change happen? I have a 69 C10 but the 63-72's 1/2 tons would all be the same, on the 73-87's did they move the lower ball joint forward to provide more caster, or the upper ball joint back? Is the later upper pushed out for better camber?

The truck already has dropped disc brake spindles using the early (63-70) ball joints and I would be swapping the ball joints into what ever A-Arms I use. Looking to see if I can get better handling without spending $400-$700.

Thanks gang.

[NSK]

Im not sure on the geometry of the arms but the biggest thing are the bushings on the cross shafts. The early models use a small sleeve and the squarebodys use a fullsize pressed in bushing. I'm sure they help with the ride but not to sure on anyting with the turning radius.

[lolife99]

I don't know of any geometry change.

The ball joints break down as follows.
60-62
63-70
71-72
73-87

[Portmod7]

Originally Posted by Hard Luck

I know that the geometry changed in the SquareBodies and it may be that they changed a few times, and I heard that there may even be an improved turning radius on some of the trucks including the Suburban.

What I am wondering is where did the change happen? I have a 69 C10 but the 63-72's 1/2 tons would all be the same, on the 73-87's did they move the lower ball joint forward to provide more caster, or the upper ball joint back? Is the later upper pushed out for better camber?

The truck already has dropped disc brake spindles using the early (63-70) ball joints and I would be swapping the ball joints into what ever A-Arms I use. Looking to see if I can get better handling without spending $400-$700.

Thanks gang.

Have you checked out the "Modern Suspension Alignment" thread? Ton's of low-budget info on this subject.

If all you are looking for is differences in control arms, and not the crossmember, then........

Caster
From what I read, more caster is easy with the arms you have, just drill a new locating hole in the lower control arm shaft. I believe they were saying around 3/4" behind the stock one, but check the thread for the correct measurement. This also moves the wheel/tire in the center of the wheel opening for aesthetics.

Camber
If the only drop you have is spindles, getting the camber you want should be easy too, as simple as convincing your alignment shop to do it for you(unless your frame is bent). To improve handling you would actually want the upper control arm "pulled in" to give a little negative camber. The drawback is that you will wear the inside edge of the tire more than the whole surface. So without increasing your tire budget and frequency of replacement, there's not a whole lot to be gained, but you can do a little without sacrificing wear too much.

Turning Radius

Not sure what you are looking for here, but you will really only notice this in parking lots or during U-turns, and I don't think you'll get any noticeable difference by simply switching control arms. It's a combination of wheelbase, steering linkage, steering box, how much physical room you have in the wheelwell to turn the tire, etc. This doesn't really "improve handling" in my opinion.

I don't see that switching control arms in your application would provide any benefit that you couldn't get with what you already have. Hope this helps!

[Hard Luck]

Originally Posted by lolife99

The ball joints break down as follows...

Thanks LoLife, I thought I had the breaks, down correctly but yours is for sure.

Originally Posted by Portmod7

Turning Radius

The turning radius is not a performance thing, it is a parking thing, and something I included as further proof of some difference. Evergreen Muscle Cars told me about that change because he has had both vehicles.

Where I am getting the rest of my information is the change of aligment specs across the generations. I had my last 69 pointed straight and the shop told me they gave me all they could which was less than the desired +5-6 Caster but more than the +1 in the original specs and they shimed the hell out of it. The specs of the later models vary but are around +5, so that is why I believe there is a change.

Might only be in the cross member lower A-Arm mounting point, as you suggest, but I would need someone to verify that as well.

In answer to your other question, The current 69 has 2-1/2" dropped disc brake spindles and just installed 3" drop springs. Rear is 4" drop muli leaf. (I think I put in enough info but always manage to leave something out, Sorry)

Thanks for your input.

[lolife99]

With a 3' drop spring,... you may have a tough time achieving your camber goal.
I would swap in a set of Porterbuilt Forward Series control arms.
This will give you much better caster numbers and also help center the front wheels in the fender opening.
(which is usually the ugly aspect of these low truck)