Ok, for you Terrain Tamers...caster shims or no caster shims??

[Ride Fly]

This quote is from another thread I started awhile back about the different options I was faced with in lift kits. I opted for the TTs obviously

The dilemma I have is whether I'll need shims. I read that the shims are needed because the shackles are longer on lift kits. Isn't the true cause, the actual height of the lift of the axle in relation to the previous point in space? Shackle length maybe the reason the axle height is higher, but the actual length of the shackle should be irrelevant.

My current shackle length is way shorter than my previous, which were 5.25" long. But my old springs were completely flat, so I hope I get a good 2-3" of lift from the TT.

Will I need shims? Did my fellow Tamers install shims during install? Or afterwards when you felt the loss of steering tracking? If shims, 2.5° or 4°?

2" skyjacker with shorter shackles , like 3.5" or 4" CtC max is perfect for 33" tires .
You will need a 2° or 4° caster shim for the front depending of the shackle size.

No presses clips on Skyjacker spring.

 

[Scott11cruiser]

I shimmed mine 4* I think when I installed.

 

[Ride Fly]

I shimmed mine 4* I think when I installed.

Thanks for your reply Scott! Did you just do the front or rear also? I've seen the rear shim added when the lift stresses the u-joint, so raising the angle of the pumpkin alleviates that. How does the 40 steering tracking to center with the TTs as compared to before?

 

[Scott11cruiser]

Just the fronts on mine, but I did measure the pinion angles. It tracks very well, stays where I aim it.

 

[brian]

The shackle is 100% the reason shims are or are not needed to correct the castor angle.
All the springs do is create a higher ride height.
The shackles, while also changing ride height do so while only changing the height at one end of the spring, therefore dropping the front of the springs and rolling the axle housing forward.
They only have 1-2 degrees of positive castor to begin with, turn that into 0 or negative 1-2 degrees and the steering gets squirrelly real quick.
How many degrees of shim that is required, needs to be measured not guessed at. With manual steering, having extra degrees of positive castor is not a good thing, they will increase the effort required to turn the wheels.