Looking at installing a rear bumpsteer kit on my AP1. There appear to be 2 different types: toe arms (T1R, etc) or ball joint type (Spoon).
Can anyone tell me the difference between the 2? Do they affect geometry the same? Any recommendations?

 

If your talking about the differences, the Spoon rear is a roll center adjuster. The T1R is a bumpsteer kit. I'd recommend Wicked Tuning, since (from my knowledge) the T1R is not an adjustable BSK.

 

Yeah, that's what I thought, but Spoon is selling it as a "Zero bumpsteer kit."
http://www.inlinefour.com/spfrzebustki.html
http://www.rhdjapan.com/spoon-zero-bump-steer-kit-56576 (this site talks about steering feel, I think they are confusing front and rear)
http://passwordjdm.com/Spoon-Zero-Bu...8171C2412.aspx

Could roll center adjustment affect bumpsteer? I guess it could...

 

The Spoon "Zero Bump Steer Kit" appears to be an extended ball joint which will raise the front roll center closer to stock (before lowering the car) and allow additional negative camber. The second link you listed says:

Quote:

It is especially practical on lowered vehicles, heightening the position of the steering gearbox.

I don't see any parts that would be used to change the height of the steering rack--what's required for a front bump steer kit. In my opinion the s2k doesn't need a front bump steer kit but the AP1 does benefit from a rear bump steer kit.

Front bump steer kit (steering rack shims):






Megan Racing rear bump steer kit (labeled adjustable toe link in picture):



More info on s2k roll centers can be found here: http://robrobinette.com/S2000RollCenters.htm

Info on the s2k front bump steer kit: http://robrobinette.com/S2000FrontBump.htm

 

The T1R is fully adjustable and basically the same design as all of the other rear BSK. I recommend going with the Wicked Tuning one vs the T1R though. The heim rod end on the T1R suck ass. Wicked Tuning using a pillow ball style rod end.

 

Good sir, heim joint = pillow ball = spherical bearing.

The only difference between these two were that the bearings and casings themselves were different designs: they were bearing/case combos that were welded onto threaded rods instead of being true rod ends. Both are available with varying quality.