Running improper shims?

Right now I have I think 3 degree shims, they seem to be perfect for my ~4.5" of lift right now.
But I will be taking my sliders out and doing the boostwerks shackle, and shackle relocation boxes. I'm thinking this will give me 1-1.5" of lift? But in any case I feel like I am at the high end of what a 3 degree shim is good for.

Will I notice the the lack of shim?

I have u bolt elimination plates on the way that I will use for proper angles, but they could be 1000 miles of road away.

I don't have your answer for you, but I just read somewhere (yesterday as a matter of fact) where someone said that extended shackles and/or shackle relocation brackets actually decrease the amount of shim you need. That's the first time I've seen that, but I think I can see how it makes sense.

I don't understand why you would need less shim with relocation brackets and extended shackles?

The shackle relocation brackets will change your geometry anyways, so all bets will be off.

Install them, measure, adjust.

xriide said:

I don't understand why you would need less shim with relocation brackets and extended shackles?

Click to expand...

I'm not entirely clear on that either, but, if it's even TRUE (which I don't know to be a scientific fact), I suspect that it would have to do with the fact that extended shackles or relocation brackets lower only one side of your leaf spring - the rear. So, if the lift you installed caused your pinion/axle to rotate one way . . .

Shoot, now that I think about it, lowering the back end of the leaf should amplify the axle/pinion rotation . . . shouldn't it?

Lowering th axle from the body at all should cause the pinion to rise, lowering the back of the spring would make that worse. I think. While, if there were some way to drop the FRONT of the rear leaf, that might bring the pinion back a little bit more toward its original alingnment.

Which you would want if you had a double cordon drive shaft in back, but not if you didn't.

Then again, there's a pretty good chance I have no idea what the heck I'm talking about.

You may need less shim, because you're changing the geometry of your leaf springs.

Instead of the front and rear bolts being lets call them 'level', the rear bolt will be 3-4" lower than it used to, changing the angle of the leaf where it bolts to your axle.

If you look in the image below, you can see the front leaf spring eye is about 4" higher than the rear one. We actually had to install shims backward to bring the pinion back down..

cal said:

You may need less shim, because you're changing the geometry of your leaf springs.

Instead of the front and rear bolts being lets call them 'level', the rear bolt will be 3-4" lower than it used to, changing the angle of the leaf where it bolts to your axle.

If you look in the image below, you can see the front leaf spring eye is about 4" higher than the rear one. We actually had to install shims backward to bring the pinion back down..

Click to expand...

Oh yes, that makes complete sense now. I was thinking about it too much as lift is lift. But yes, I can see how the shackle lift is working as your shim now.

Thanks :cheers: