[56Rick]

I see a lot of talk about changing the upper control arms on Tri 5's to improve handling via more Caster. How do the 'improved' control arms add the caster? Do they mount differently or did they move the upper ball joint.
What keeps a person from altering a stock control arm??

 

[Shadetree55]

I see a lot of talk about changing the upper control arms on Tri 5's to improve handling via more Caster. How do the 'improved' control arms add the caster? Do they mount differently or did they move the upper ball joint.
What keeps a person from altering a stock control arm??

I think the triangulation of the upper arm just kicks the upper ball joint back further. The control arm shaft is machined to place the control arm a bit further back on the shaft.

 

[Budsin's mad mechanic]

I think the triangulation of the upper arm just kicks the upper ball joint back further. The control arm shaft is machined to place the control arm a bit further back on the shaft.

There was a post on this site a while back about cutting the brackets the upper control arm fasten to on the frame and moving them outboard to gain positive caster. I did this but only gained about three degrees which isn't enough.Which means in my situation the arms or the cross shafts that add three degrees would not have been enough either.I purchased adjustable upper a frames from SPC ,then we could get 5 degrees that made it drive straight down the road with no wandering.I believe each car is different because of the equipment it uses.The earlier threads answer is correct the parts move the upper ball joint towards the rear of the car which adds positive caster

 

[Shadetree55]

There was a post on this site a while back about cutting the brackets the upper control arm fasten to on the frame and moving them outboard to gain positive caster. I did this but only gained about three degrees which isn't enough.Which means in my situation the arms or the cross shafts that add three degrees would not have been enough either.I purchased adjustable upper a frames from SPC ,then we could get 5 degrees that made it drive straight down the road with no wandering.I believe each car is different because of the equipment it uses.The earlier threads answer is correct the parts move the upper ball joint towards the rear of the car which adds positive caster

which is basically how the newer modern alignment uses cam bolts for alignment. No shims, just cam washers that move the arm back and or out for caster and camber. I'm really surprised an aftermarket company hasn't designed something like this for our cars.

 

[56Rick]

which is basically how the newer modern alignment uses cam bolts for alignment. No shims, just cam washers that move the arm back and or out for caster and camber. I'm really surprised an aftermarket company hasn't designed something like this for our cars.

That's kinda what I was getting at. After all these years, we still have to pay $300 plus to get new A-arms for better handling. Sure looks like a kit to use our original control arms would be something that might be available and cheaper too!

 

[Shadetree55]

That's kinda what I was getting at. After all these years, we still have to pay $300 plus to get new A-arms for better handling. Sure looks like a kit to use our original control arms would be something that might be available and cheaper too!

you can buy offfset shafts and bushings by itself but those only give you around 2 degrees extra caster over stock

 

[hotrodg726]

you can buy offfset shafts and bushings by itself but those only give you around 2 degrees extra caster over stock

If you are Lucky

 

[Rick_L]

I was going to say 1-1/2 degrees on the offset shaft.

You can do this without parts. Break the weld that attaches the control arm frame bracket to the frame in the front only. Rotate the front of the bracket in the outboard direction 3/8”. Re-weld the bracket to the frame.

Now, you’re going to have a lot of stuff in the way to do this on a fully assembled car. It’s something best done with the front sheet metal off and the engine out, or at least as much as possible. Also, not sure if 3/8” gets you a full 5 deg. but it will be close.