Modern Spindles

[Rick_L]

A C3 Corvette spindle is approximately 1" taller than a 55-57 spindle. But it also has 7º of steering axis inclination compared to a 55-57's 3.5º. The extra height of the spindle gives you a favorably different camber gain curve. The extra steering axis inclination is better suited for wider wheels and tires, as it reduces the scrub radius.

You can put a C3 Corvette spindle on a 55-57 by making a spacer bushing for the lower ball joint pin, and shortening the upper control arm about 3/4". It also lets you run the C3 12" rotors. Down side is that there's no dropped spindles available.

A tall upper ball joint would get you the camber gain.

The reason for the camber gain is primarily from having the upper control arm having the ball joint higher than the control arm's shaft.

[rockytopper R.I.P 5-13-2017]

Rocky, "alignment" is not the same as "geometry". You can get the same alignment with just about any suspension. Alignment refers to the angles of the tires at rest, and while turning at ride height, things like caster, camber, and toe. Geometry refers to the static and dynamic position of the suspension, which is determined by the angles, lengths, and positions of the suspension components. Geometry determines things like anti-dive, scrub radius, roll centers, ackerman, etc.

I agree, however if you tried to align a stock trifive with the specs I listed I can assure you the geometry would be way screwed up. The adjustable upper arms allow for the modern alignment settings as well as give you the corrected geometry at the same time. It may not be exactly "corvette geometry" but it will yield very similar handling results in the end. I believe the stage II package is designed around the C5 vet geometry according to Marcus. If you really wish to know I'm sure he would give you that information but be prepared to talk for hours when you call him.
Rocky

[Rick_L]

rockytopper, you are reading way too much into the adjustable control arms.

You can't get 5º of caster with a 55-57 front end unless you modify something to move the upper ball joint to the rear about 1".

If you try to install the 1" taller ball joint, you need shorter control arms.

Those tinker toy control arms possibly allow you to do that. But it's not because of the arms, it's what you might be able to do with them.

And there's no way a street driven car can utilize 2.7º of negative camber. Your tires will wear out in 100 miles, maybe 25.

[rockytopper R.I.P 5-13-2017]

rockytopper, you are reading way too much into the adjustable control arms.

You can't get 5º of caster with a 55-57 front end unless you modify something to move the upper ball joint to the rear about 1".

If you try to install the 1" taller ball joint, you need shorter control arms.

Those tinker toy control arms possibly allow you to do that. But it's not because of the arms, it's what you might be able to do with them.

And there's no way a street driven car can utilize 2.7º of negative camber. Your tires will wear out in 100 miles, maybe 25.

Rick, I never said to use 2.7 deg negative caster on a street driven car. The Tinker toy arms as you call them do in fact move the upper ball joint aft when adjusted. I'm not sure if it's one inch or how much but it changes the geometry for the better. I have the tinker toy arms laying on the roof of my nomad I will check to see what alignment specs are specified for the trifive vs the a-body version that I have on my cutlass and report back.
Rocky

[Rick_L]

The arms don't change the geometry for the better. They possibly enable the tall ball joints by having enough adjustment. They possibly enable an alignment of +5 degrees caster.

Thing is, you can get the same thing with nonadjustable control arms that have the ball joint moved rearward. And the tall ball joints will require you to add shims to get alignment, which is easy enough to do.

And I'd be concerned that the adjustable arms would just overwhelm the average guy or the typical front end alignment tech.

[rockytopper R.I.P 5-13-2017]

It's confirmed I can set the front alignment on the nomad same as my Abody setup.
Rocky

[chevynut]

Again, "alignment" isn't the same thing as "geometry". You can get Corvette alignment with the stock Tri5 front end with the exception of caster, which you can get with simply a different set of upper control arms. That doesn't mean it has anywhere near the geometry of the corvette suspension.

I agree with Rick...I have never been a fan of adjustable control arms.

[rockytopper R.I.P 5-13-2017]

Love or hate these arms are a very simple design. Two turn buckles. When you adjust them to spec the geometry is totally changed much like what Rick said the upper ball joint is pulled aft creating a totally new geometry in the suspension travel because you have changed the pickup points in the mechanism. Just an FYI it is far easier to align a car with these than using the old shim method. No shims are needed. I agree with Rick in that most alignment shops can't even align to a 3 dimensional alignment spec as I showed. I used NTB for my last build because they have the equipment that will. I dropped the car off gave them a spec sheet as shown above at the counter and picked my car up at lunch. I didn't even talk to an alignment person that I had the arms installed. It should be easy enough for anyone to figure out how to adjust 2 turnbuckles and watch a graph on the screen.

First link below is a picture of the C4 front suspension which you are very familiar with. Notice the top arm geometry is such that the spindle is slanted aft. If you compare this to the SC&C setup in the second link they look almost identical meaning they both have very similar geometry. Heck they even sale these arms to improve the c4 stock setup 3rd link. If you guys know of fixed arms on the market that do this I sure like to see them because most don’t have near as much geometry correction built in as these adjustable arms provide.

Rocky

C4 front
http://www.vettemod.com/forum/imagehosting/12695256a4f8b0e8f.jpg
SC&C front
http://www.carcraft.com/featuredvehi.../photo_15.html
http://scandc.com/new/node/69

[Rick_L]

Almost all of the tubular upper control arms for 55-57 Chevys have 5º of positive caster built in.

To install the long upper ball joints only means more shims at the control arm shaft. I don't know if any of the long ball joints on the market are available in the 55-57 Chevy bolt pattern.

I don't think you understand what Chevynut and I are describing to you.

[chevynut]

When you adjust them to spec the geometry is totally changed much like what Rick said the upper ball joint is pulled aft creating a totally new geometry in the suspension travel because you have changed the pickup points in the mechanism.

It doesn't change the suspension geometry, just the caster. Nothing else changes. There is no new geometry.

First link below is a picture of the C4 front suspension which you are very familiar with.

No, the first link is not a C4 front suspension, it's a C5 rear suspension. What you are describing is caster and I don't believe a rear suspension typically has any caster. It's just the way they have the suspension sitting on the ground.

If you compare this to the SC&C setup in the second link they look almost identical meaning they both have very similar geometry. Heck they even sale these arms to improve the c4 stock setup 3rd link. If you guys know of fixed arms on the market that do this I sure like to see them because most don’t have near as much geometry correction built in as these adjustable arms provide.

It's pretty clear to me that you don't understand what the term "suspension geometry" means. You keep talking about alignment. Caster is alignment. How caster, camber, roll center, instant center, bump steer, etc. CHANGE during suspension travel is a function of suspension geometry, not of alignment. There is no way you're going to get C4 suspension geometry on a stock tri5 frame with aftermarket parts because the pickup points are all different. You can improve on it some, but that's about it.