To GULSTRAND OR NOT TO GULSTRAND??

[67steve]

Thanks for the clarification Carl. What is the advantage of the ATS AFX spindle?

Thanks,

SteveM

[TitoJones]

Thanks for the clarification Carl. What is the advantage of the ATS AFX spindle?

Thanks,

SteveM

It adds a similar improvement to the front geometry as the Guldstrand mod. Since you read over 5 hours of G mod info on this site, I think you have a pretty good grasp of what the mod does for the car, but for those who do not this is what it all boils down to-

The F body front suspension lacks a good negative camber curve. The fixes for this shortcoming is a relocation of the upper control arm attachment point on the frame (G-mod) or putting on a taller spindle. We made a taller spindle to help improve the car's handling characteristics. When we were finished engineering and testing the geometry of our AFX spindle we found that on an otherwise completely stock frame, we could get more negative camber gain than either a G-modded vehicle or a DSE weld in coil over kit. When we started adding tubular control arms and bumpsteer adjustable outer tie rod ends, we recorded geometry data that equaled- and in certain areas- surpassed $6700 aftermarket subframes. All of this in a simple bolt on spindle.

Tyler

[67steve]

Is a taller spindle the same thing as a drop spindle? I am new to alot of these terms. Reading 5 hours of info for me is probably like reading 30 minutes to someone else. I start to digest all the info the next day after reading.

Thanks , Steve M

[Boulder69]

Not the same thing. The spindle is actually taller from ball-joint to ball-joint, resulting in a better camber curve. Dropping the upper control arm mounts changes the angles in a similar way.

Many taller spindles also have drop, but any drop more than an inch or so begins to cause other issues. Dave Pozzi has tons of info on that. The ATS spindle does have some drop, but I believe it is just a hair under an inch and was neccessary to clear the C5 bearing packs. Shouldn't cause any of the issues Dave mentions, such as tie rod interference with the wheel.

Which brings up what I personally feel is another huge benefit of the ATS setup - no more old-school bearing/spindle pin technology. The C5 bearing hub seems much more safe and trouble free. No burned up bearings from open road race use, and your life isn't riding on a 35+ year old stub of steel sticking out there. I broke the pin clean off of the spindle on my old 72 Jimmy once, good thing I was pulling in the driveway when it happened or I could have been seriously injured or killed. I'm not gonna beat my camaro like I did the GMC, but that experience still haunts me a bit.

Herb Adams has a great book that goes in-depth on all of this suspension geometry stuff. Tony Huntimer has a fantastic book on all aspects of PT cars, I highly recommend that one as well. -eric

[Z06vet]

How will the use of 2" drop springs affect the use of the taller spindles and/or the guldstrand mod? I will be installing the springs soon, and would like to do everything at once. Scott

[baz67]

How will the use of 2" drop springs affect the use of the taller spindles and/or the guldstrand mod? I will be installing the springs soon, and would like to do everything at once. Scott

Nothing bad. In fact it will help in getting the UCA in a better position and lower your center of gravity.

Edit: Now you do not want to do the Guldstrand mod with the taller spindle as it can do undesirable things to front geometry.