Just wondering, gunna be running 20s/22s soon as i get them, im gunna drop the torsions accordingly, but how low can i really drop the *** end without losing 4x4? I live in ontario, i used 4x4 once this winter.... Its barely used in winter, BUT i still dont wana break my 4x4, screw it up, and or not have it at all for re-sale or if i get hung up on some ice...

The torsions will crank down nicely, throw the 20s/22s on then get a wheel alignment ofcourse, but the rear end, i wana throw maybe 2"? 3"? 4"? blocks in? all possibilities?

 

Its a 98 gmc jmmy 4x4, i know you can drop down queit abit. just once front end is down far as i can go (safely) let me know how much i can drop torsions, and then i just wana flush down the back, 4" would be more than enough by far. might even lean the back end down, so 3-4 in the back is safe?? :/ just ordering those 30$ blocks from summit with the U bolts

 

I think lowering the front 2" and the rear 3" blocks is the safe route ive seen, but just wondering if thats gunna be ok for 20s/22s also if 4" blocks are possible that would be ideal

 

Each steering linkage and suspension component has a range of motion that it’s designed to operate within. When front ride height is out of spec, many of the components are pushed beyond their designed limit. Both torsion bars, all 4 CV joints, all 4 ball joints, both shock absorbers and both outer tie rod ends are all affected by incorrect ride height. Expect these parts to wear out rapidly when front chassis ride height is not within factory specifications.

Front chassis ride height is the vertical distance between the lower-most inboard point of the steering knuckle, nearest the ball joint, to the center of the lower control arm pivot bolt.

1996 & newer:

4WD (except ZR2) = 4.6” to 5.0” (4.8” is preferred)

4WD ZR2 = 4.6” to 5.2” (4.9” is preferred)

 

Capn does that mean outer pickup point minus inner pickup point? Are ball joint centers different then "lower most inboard point of steering spindle"What is the ride ht. for a s10 pickup

 

This applies to 4WD only. 2WD is not adjustable. GM T body, (Pickup and Blazer) use the same specs.

Lowest inboard point of the knuckle, not the ball joint. Easiest way is measure from the knuckle to the ground, and from the center of the control arm bolt to the ground, (the 2 horizontal lines in the image below). Then subtract the knuckle measurement from the control arm bolt measurement. That will give you front chassis ride height. Vehicle MUST be on level ground, front to rear and side to side, with all 4 wheels on the ground. Before measurements are taken, jounce the front end 3 or 4 times and let it come to rest.

 

Oh I see. On a four wheel the bj is over the lca. On 2wd you have to use only the pivot points to calculate roll center and bump steer, and such. I guess the 4wheel guys arent concerned with that. They just want to lift it and put some big tires on it.

 

Chassis ride height, (aka Z height) on RWD is the vertical distance between the center line of the front lower control arm pivot bolt, and the inboard corner of the lower ball joint. Spec is 2.6" to 3.0" If it is out of spec, unless something is bent or modified, the springs are weak and need replacement. Roll center?? I taught front end for I can't remember how many years, and never heard that term. Bump steer is caused by the steering linkage not being level. It's adjusted by loosening the idler arm mounting bolts and moving the center link up or down, then tighten the bolts.

 

Hook your a pretty smart guy. The roll center is the intersection of two lines drawn from instant center to opposit ground contact point. Tell me how to put a rack and pinion on my truck when the rack is wider then the lca pick up points?

 

Roll center: fancy catch word for suspension center of gravity and how it affects body roll

Rack & pinion... I assume you mean the knuckle attaching points, rather than LCA. Find a narrower rack Have you looked into 1974 through 1978 MustangII? Those racks are a favorite with custom builders. Easy to mount, and very short. Buy Cardone Rack and Pinion Complete Unit - Hydraulic Power - Remanufactured 22-200 at Advance Auto Parts