I am getting close to firing up the 65 Cutlass after a 2 year frame off resto. I need to get the front end aligned and I was wondering if any one has advise on the specs for a good driver. I know the original specs allowed for the 1 finger turn but I want good handling and road manners. I have installed new tubular upper and lower front control arms and tubular in the rear with added Edelbrock frame braces and a rear sway bar. The car has 14 inch wheels with 70 series tires all around. I also went with a variable rate steering box and the stiffer KYB gas shocks.
Thanks--

 

Specs for a good driver. Yeah, use factory specs.

I don't think those tubular arms redesign the front suspension. The long/short control arms are engineered to maintain a constant wheelbase as the suspension works up and down while going down the road. This prevents the tires from scuffing sideways. The factory specifies a small amount of positive camber when the car is on the alignment machine because the car rises slightly under motion, pulling the camber closer to 0*.

I like the caster to be on the positive end of the adjustment. Think about the wheels on an office chair. If you push the chair with the casters ahead of the pivot point (negative caster) they wiggle around until they flip around behind the pivot point (positive caster). Positive caster gives you wheels that want to follow a straight line instead of fighting it.

About that variable ratio box. Because the ratio changes as you turn the wheel, it's essential that the box is centered when the front wheels are straight. If not it could induce a pull or drift into the front end. The alignment guy will set the steering wheel straight and then adjust the front wheels straight from that. The one thing you can do is pop the horn button and check that the center mark on the wheel is lined up with the center mark on the shaft. If not, you might not get the steering box properly centered.

A word about wheels and tires. I don't care about wide wheels or tires. I want the tire diameter and the wheel offset as close to stock as possible. The center line of the tire needs to intersect the center line of the ball joints where the rubber meets the road. Anything else puts more stress and wear on ball joints and can cause steering issues if it's off far enough.

 

who's arms did you get I would think they woud have a base set up for their
product .

 

The tubular arms are Pro Comp by Southwest Speed. They do have the offset on the attaching arm to eliminate the need for a lot of shims. I was advised to go with 1 to 2+caster, 1 1/2 camber and 1/16 toe. The front suspension is much stiffer with the stiffer gas shocks and I also cut the springs a little for lowering the front end and make the springs a little stiffer.
Hey Highwayman-- Do you know what wheel tire combo gives the best alignment with the ball joints. I think I have 14 x 6 inch rims with 4 inch set back and the 225/70 tires. That is neg 1 1/2 on the camber

 

You have changed the original suspension geometry, so you need to get advice from people who have made similar changes, and not from people who are accustomed to stock suspension behavior.

- Eric

 

Thanks Eric, I am a little out of my element with the mods. But I'll give it a shot.



Yeah, stock.


I think the 65 came with 14 inch wheels didn't it? 14x6 is fine and 225/70 tires should be fine too. That sounds real close to stock size. Back space isn't what I look for, it's offset. Back space is the distance from the wheel mounting surface to the back of the wheel. Offset is the distance from the mounting surface to the center line of the wheel. So if you get a wheel 2 inches wider and add 1 inch to the front and 1 inch to the back, the offset stays the same. A reversed wheel that adds 2 inches of offset to the front is hard on joints and makes the steering harder.

About those alignment specs. GM specs are for negative caster. Putting that much positive caster in the front end should not cause excessive tire wear problems and will be great for going in a straight line. It will add some effort to turning in tight turning situations but with power assist you probably won't notice much. I'm puzzled that you seem to have build a nice setup for tight road work. The positive caster will fight you in quick, tight turns.

Stiffer suspension shouldn't affect the alignment specs but the lowering might. 1 ½ camber sounds excessive and I have no idea why to do that, but I'm open to learn. Factory spec is ¼ to ½ +. Factory toe is 1/8 to 3/16. You might be alright with 1/16 toe for tire wear since everything is new and tight, but if the car wants to wander you might try 1/8.

What I would do with the alterations you've made is start with factory specs on camber and toe and watch the tires for wear. Measure tread depth across the face of the tires to ensure it wears even. Also run your hand across the face of the tread. It should feel smooth. If it feels like sawteeth something ain't right. Then tweak as required.

 

Thanks for your advice. I am looking for a tight driving car however I was pretty happy with the original handling before I did the resto. I looked around and got those specs from a pro touring set up. I also referenced www.hunter.com/pub/undercar/2573T/index.htm
It is a pretty complicated explanation so I may be misinterpreting it.
I also know these cars had an odd geometry so the factory specs may be the best starting piont for me. So if I understand your recommendations it would be 0 caster,1/4 to 1/2 positive camber and 1/8 toe?

 

Yeah Mike, I think that I would stay close to factory specs for a starting point. You have some nice mods but nothing that sounds radical. Camber and toe are more about tire wear than handling.

I did flip the castor setting years ago on my ElCamino from neg 1 ½ to positive 1 ½ because I was doing a lot of highway cruising. It worked great and drove like it was on rails. On properly banked curves it almost steered itself. But you do give up a little on the tight handling end.

Back to reality, unless you have access to alignment equipment to do the job yourself, the alignment guy may well tell you factory specs or go somewhere else.