mLeach

But witches float!

glagola1

We need to have a webinar.

The one thing that is a potential gotcha is that these are not sliding adjusters. They are rotating adjust which will affect caster and that is not legal. I had not thought of that until I saw Jason Rhodes quote.

Let me repeat it for the 4th time: THE TOTAL HEIGHT OF THE JOINT IS NOT AN ISSUE IF THE SHANK AND BALL ARE DIMENSIONALLY SIMILAR TO STOCK. ALL THAT HAPPENS ABOVE THE BALL JOINT IS IRRELEVANT TO SUSPENSION MOTION.

josh7owens

Can we go back to talking about this now? Have we came to conclusion 12.5" ride hieght is ideal due to linear toe curve and tire clearance issues? I've been at this ride height since day one.

josh7owens

Wouldn't this make the J's/hardrace camber joints illegal since they change the spacing between the hub and lower suspension arm?

.... Here we go again. FML.

from 2012 rule book...

14.8 SUSPENSION
A. Ride height may only be altered by suspension adjustments, the
use of spacing blocks, leaf spring shackles, torsion bar levers, or
change or modification of springs or coil spring perches. This does
not allow the use of spacers that alter suspension geometry, such as
those between the hub carrier and lower suspension arm.

Zeus2k

Someone correct me if I am wrong, but that is why the s1 joint is legal while the l1 is not.

marcrx5

The standard J/Hardrace camber joints are legal. Because the lower ball joint bolts to the knuckle, any spacers will directly effect the location of the lower control arm pivot point. It basically allows you to lengthen or shorten you knuckle length. This is different from the SPC joints, because they are replacing the upper ball joint on the upper arm, and I'll argue that it doesn't matter what the upper ball joint looks like, it is not changing the pivot location on the knuckle.

I confirmed the dimension betwee the base of the OEM/Js to the taper on the ball joint, and it is the same.

josh7owens

ok, thanks!

marcrx5

I actually need to modify what I said, I keep referring to the pivot points at the knuckle / ball joint taper, but this actually happens at the ball I the ball joint. I'm back on te same page as many in this thread about the uppers, the distance between the centerline of the ball and the taper needs to remai constant.

This doesn't change my thoughts and comments on the Js lower ball joints.

Random1

12.5" rear ride height is one that I arrived at based on rear spring rates of 750 lb, shock body length, cut bump stops (barely enough to protect the shock), and shock damping available. Using an o-ring on the shock shaft I was able to monitor the maximum compression stroke for various course and daily driving conditions. When the o-ring ended up just touching the bump stop for most conditions the ride height ended up at 12.5". There are extreme conditions on the street that force the o-ring up into the bump stop some amount, but for autocross that never happens. I then adjusted the front ride height to achieve a rake that performed well for power-on coming out of corners. So, there really is no magic to 12.5", it just seems to work well. Depending on how much compression force is available in your shocks, YMMV. I know that one click too little on compression allows my car to scrape the exhaust on bumps that normally won't with more compression. You really want to make sure the bump stops are not engaging when the car is loading up in corner or slalom transitions.

One goal was to avoid the toe out dynamic which I thought was there, but at the time I did not truly know where in the stroke it took place. Based on what was measured in this exercise most STR setups will not have to worry about it (as Matt G - glogola1 - had thought).

Now that I have seen this curve it tells me that the my setup is operating in a nice range from the rear toe-in perspective. It would be nice to have more measurements points to get a better feel for how linear the curve really is. I may do that when I rebuild my shocks in a month or so. It would also be nice to have someone else validate the curve for an AP1 and measure it for an AP2. Any volunteers?

762

Random1, I'll pm you on the AZ boards to discuss details, but I am waiting for some new springs to come in. When they do and if you would like we could do the measurement on my car while springs are being swapped.