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Discussion Starter · #1 ·
what is the correct z height or trim height for a 2006 sierra 2500hd?
let's say for arguments sake i put in new torsion bars, bushings, yada yada.
how do you know how far in to crank in the torsion bar adjusting bolt on each side?

i ask because i was messing with mine, when i got new tires and alignment a couple years ago the shop cranked on the torsion bar bolts to raise the front so the rims (aftermarket) would clear the front fender. since then the front suspension was harsh. i fixed the clearance issue and backed off my torsion bar bolts, but now i need some reference where to set them. i don't care about the front sitting lower than the rear at this point, just looking for what gm would have done on the assembly line setting it.
and i have a 2006 service manual, and they only list z height measurements for the 1500 models, nothing for 2500/3500 ?
 

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usually GM has about 2 - 2.5 inches higher in the back. Really it all depends where you want it. Just make sure your wheels are not bowed in or out so as not to increase inner or outer tire ware.
 

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Discussion Starter · #3 ·
well i backed the torsion bar adjustment bolts all the way out, then turned the adjustment bolt in only 1 turn. now my front is way lower and alignment is all off now but the front rides so much better just going up and down my street.

gonna replace both front hubs again, and swap out the duralast front axles.
I also got reply from timken regarding the hubs, i can run them without the front axles so i might try that. then go get the alignment done.

question regarding z height or trim height... i don't expect everything to by symmetric and even meaning i turn each adjustment bolt the same same number of turns and have the left and right side even. I understand the number of turns on the adjustment bolt does not affect preload but only wheel height or how much the lower control arms move downward and the body upward (the weight on the bar is always the same).
so that means you turn the adjustment bolt in however many turns you need to get the correct Z height measurement? And if you have the same Z height measurement on each side then the truck should be level left to right (provided there's no collision/frame damage) ?

My service manual details Z height measurement as the vertical distance between the lower control arm pivot point to the bottom corner of the steering knuckle. So my big question is what is that Z height measurement supposed to be for a 2006 2500hd? Because the book only gives Z numbers for 1500, yukon, suburban tahoe and they are all pretty much 4.3 to 4.8 inches, some being 3.5 to 4.0 inches.
... or if you look at it from a design perspective, how do they come up with that Z number to begin with, what determines it? is the lower control arm supposed to be closer to 90° with respect to the torsion bar, or the front cv axle straight ?
 

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Discussion Starter · #4 ·
regarding last post, what i want to know is how far do you turn in the adjustment bolt to obtain the nicest ride? I'm not looking to raise/lower the front for looks or clearance, I don't care where it sits except at the point that it's supposed to sit at to give best ride and I assume also the least wear & tear on components. thanks.
 
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