Question for the Suspension Gurus

[BIGCHEVYFTW]

I have a set of tubular control arms that add 4.5 degrees of positive caster to a stock spindle on a 68-72 GM
A-Body what would happen if i used a spindle that is 3/4" taller then stock? would this make a mess of things?

[killer69]

what spindle is 3/4" taller? what are you doing about the steering arm? just use a tall jall joint. there will be no issues other than a good alignment

[BIGCHEVYFTW]

Thanks for the reply.

The spindle is CPP's C5 spindle. I placed an order for them and canceled it because, (Erin) couldnt tell me anything about them other than they are stock geometry and use a c5 Hub and brakes and stock steering arms.

[BIGCHEVYFTW]

Can you explain the tall ball joint theory and do you use them on the upper arms or lowers or both?

[Vicinity]

The upper, it basically does the same thing as a taller spindle, the balljoint is moved up however tall. It's a cheap way to change your geometry.

[BuzzKillian]

A taller spindle would decrease your caster a very small amount. An alignment could easily get back anything you would lose.

[UMI Tech]

Can you explain the tall ball joint theory and do you use them on the upper arms or lowers or both?

Increased spindle height in the case of the A-body improves the camber gain and allows the contact patch to remain flat, or at least flatter than, stock geometry - depending on how much spindle height we use.

If you look straight on at upper a-arm height from the front of the car you can see how the upper a-arm angles downward from the centerline of the car to the outside. As you roll into a turn, the tire cambers outward and "rides on the sidewall" in some cases. If we hold everything constant and add spindle height you can see how the upper a-arm gets flatter and in some cases can tilt upwards. This gives the tire a fighting chance to be flat at the contact patch during cornering.

A car with proper spindle height can use a tire-friendly static alignment (meaning the car doesn't know any different when cruising) but still pull the tire in properly when the car is pushed hard.

We tend to use 1/2" tall upper ball joints as a budget friendly first improvement. These combined with a moderate lowering can get the upper a-arm a lot closer to flat. Next is 1/2" tall lowers and uppers, and so on. Tall spindles accomplish the same thing but at a larger expense and as you've seen, some are high quality, some low quality, some expensive, some cheap...

ramey