crew cab lift info

[84jp]

looking to get a lift kit but i don't know how high i want to go. still have to keep it street able (keep in mind it is a tow rig i tow my mud truck every weekend)
would like to fit 35s also
it is a 1991 v3500

[Killroy1942]

Well, you could go with 4 inch lift springs up front, and a rear shackle flip. That would clear 35's with some mild trimming.


These guys have a solution

http://offroaddesign.com/

[sjracer]

i would go 4" lift, springs front/blocks rear since its a tow rig this will work fine. by keeping the lift lower you are still nice and stable while towing. you will still need a new front driveshaft -longer and for a higher angle, and your rear driveshaft will need to be lengthened.

you will need to relocate the front sway bar mount, and get a drop pitman arm or a raised knuckle steering arm to fix the steering geometry. not doing this will give you a shitton of bump-steer.

i would not go a rear shackle flip if its a tow rig, you can carry more weight with the shackles in thier current configuration.

also plan on longer brake lines.

Offroad Design does have everything you will need

[jasongjco1]

Heres how I lifted my front 3 inches with blocks in the rear. Pretty cheap and should ride better than lift springs.

[Cheepin]

Originally Posted by sjracer

i would go 4" lift, springs front/blocks rear since its a tow rig this will work fine. by keeping the lift lower you are still nice and stable while towing. you will still need a new front driveshaft -longer and for a higher angle, and your rear driveshaft will need to be lengthened.

you will need to relocate the front sway bar mount, and get a drop pitman arm or a raised knuckle steering arm to fix the steering geometry. not doing this will give you a shitton of bump-steer.

i would not go a rear shackle flip if its a tow rig, you can carry more weight with the shackles in thier current configuration.

also plan on longer brake lines.

Offroad Design does have everything you will need

This except you do not need to mess with your driveshafts.They will fit fine.Just order a complete kit.This should include brakeline drop brackets,shocks,leaves,steering arm blocks and rear U-bolts.Call ORD for thier sway bar quick disconnect then leave it on.

[sick_sahara_yj]

"i would not go a rear shackle flip if its a tow rig, you can carry more weight with the shackles in thier current configuration."

I do not agree with that statement at all. I built a 1997 chevy crew cab dually with 37 inch hummer tires and 6 inch front springs. the rears are a small lift with shackle reversal. It daily pulls a large bumper pull dump trailer and a small excavator. The combo is about 12-15k pounds depending on what he has in the bed. My customer claims it pulls better (has better characteristics) than the factory and even rides better.

I consistantly build tow rigs with 6-8 inches of lift (NO FREAKING BLOCKS) and 37 inch tires that pull dozers, backhoes, and more and they pull just fine. I do not recommend blocks in the back of any towrig. I recommend spending the money on good springs.

I also recommend you go to the tow rig section and search builds there and see what others are building.

My crew cab (73) has shackle reversal in the rear, 6 inch springs in the front, 37 inch tires and a cummins 12 valve with 5 speed. I have put this combo to work in many trucks and works well because the tires are inexspensive and have a heavy load range and good sidewalls.

[Pietro]

Originally Posted by jasongjco1

Heres how I lifted my front 3 inches with blocks in the rear. Pretty cheap and should ride better than lift springs.

YIKES

[sjracer]

Originally Posted by sick_sahara_yj

"i would not go a rear shackle flip if its a tow rig, you can carry more weight with the shackles in thier current configuration."

I do not agree with that statement at all. I built a 1997 chevy crew cab dually with 37 inch hummer tires and 6 inch front springs. the rears are a small lift with shackle reversal. It daily pulls a large bumper pull dump trailer and a small excavator. The combo is about 12-15k pounds depending on what he has in the bed. My customer claims it pulls better (has better characteristics) than the factory and even rides better.

I consistantly build tow rigs with 6-8 inches of lift (NO FREAKING BLOCKS) and 37 inch tires that pull dozers, backhoes, and more and they pull just fine. I do not recommend blocks in the back of any towrig. I recommend spending the money on good springs.

I also recommend you go to the tow rig section and search builds there and see what others are building.

My crew cab (73) has shackle reversal in the rear, 6 inch springs in the front, 37 inch tires and a cummins 12 valve with 5 speed. I have put this combo to work in many trucks and works well because the tires are inexspensive and have a heavy load range and good sidewalls.

i too hate blocks, but i was suggesting it as a cheaper route to replacement springs. but, there are thousands and thousands of trucks lifted with blocks out there. they too, tow much like your saying. one of my trucks had 4" blocks on it for more than a dozen years with no problems towing or wheeling. was it the best way to do it, no. but it did work flawlessly. i certainly would not put much more than a 3-4" lift block in the rear, and with a 6" lift like your saying i would definately not do that. rear springs are the right way to go.

question: when you are performing said shackle flips, are you leaving the rear diff rotated up? are you doing any kind of cv driveshaft, or other rear driveshaft mods? are your rear shackles one piece or two piece?

my reasoning is, your taking the rear driveshafts u-joints out of synch with each other when you rotate the diff up. maybe with the longer length of your setup (being a crewcab) it lessens the effect of the u-joints not being paralell anymore (and that cummins). my experience is with short/longbed trucks, not with 3+3's, so i will trust that you have more experience here.

[ehjorten]

Originally Posted by sjracer

...i would not go a rear shackle flip if its a tow rig, you can carry more weight with the shackles in thier current configuration...

I am contemplating some changes to my '91 V3500 and one of the changes is a shackle-flip. I keep hearing statements like this one and I wonder why? Why not a shackle-flip for a tow rig? Why can you carry more weight?

I am thinking that maybe it is collapsing a stock shackle which was designed for tension not compression. Or maybe if you aren't careful with the geometry you can invert a shackle.

I'm planning on a 4" shackle flip and I have modeled the geometry by carefully measuring on the truck and recreating it in CAD at work. I'm a mechanical engineer and work in the heavy truck world so maybe I am getting a little nerdy about it, but hey...I like to understand the geometry.

A couple of things that I don't like is that in order to get the 4" of lift you need to drop the rear spring eye double that amount (~8"). This gets the rear of the spring hanging below the bumper and body work. Also...if you don't relocate the hanger a little farther forward (which most aftermarket kits do), you get a little cozy with inverting a shackle when the axle drops. It is even more exaggerated with lift springs. My CAD geometry tells me that by doing the 4" shackle-flip you rotate the pinion up about 8.3° and with 4" of lift you move the axle ahead about 1" (6" of lift about 1.5" and 8" of lift about 2").

Anyways...all of this needs to be accommodated for in things like your driveline length. I recently got my drivelines re-tubed (front was shot, fwd rear section was bent, and rear rear section was too short) and I don't want to spend any more money on that!

Anyways...my point was...I don't understand the statement that you shouldn't shackle-flip a tow rig. If I am missing something please let me know.

[sick_sahara_yj]

I build lots of these trucks in my shop. With the last crew cab I completed, we did not have to modify the drive shafts angle, just the length. We upgraded to 1410s throughout the rear so that there was more strength.

I always redo the spring perches and reset the pinion angle. It is how I was taught and I have had wonderful results with it so I stick with it. When lifting a crew cab, replacing the carrier bearing is a must. I dont care who says what! If it is old, replace it because it will start causing vibrations.

On a tow rig, I would not skimp on the suspension. Afterall, you are using it and pulling weight behind it. If it were just a trailer queen trail rig, then skimp if you like, but I prefer to have the right parts in it the first time and not worry.

The guy I built it for says it handles tons better now towing than when it was stock.


this is his usual daily haul set up

[Pietro]

Originally Posted by sick_sahara_yj

I build lots of these trucks in my shop. With the last crew cab I completed, we did not have to modify the drive shafts angle, just the length. We upgraded to 1410s throughout the rear so that there was more strength.

I always redo the spring perches and reset the pinion angle. It is how I was taught and I have had wonderful results with it so I stick with it. When lifting a crew cab, replacing the carrier bearing is a must. I dont care who says what! If it is old, replace it because it will start causing vibrations.

On a tow rig, I would not skimp on the suspension. Afterall, you are using it and pulling weight behind it. If it were just a trailer queen trail rig, then skimp if you like, but I prefer to have the right parts in it the first time and not worry.

The guy I built it for says it handles tons better now towing than when it was stock.


this is his usual daily haul set up

I just bought a set of those 37's for my M1031 CUCV on a set of older Ford rims. I put one on my balancer and required over 10 ounces on one side. Are you guys balancing these tires at all on DD machines or skipping it out of futility?

[sick_sahara_yj]

all mine get balanced. sometimes you get tires that are way off. when I get those, they get marked and put in a stack for offroad use only.

[92solidaxlechevy]

Originally Posted by Pietro

I just bought a set of those 37's for my M1031 CUCV on a set of older Ford rims. I put one on my balancer and required over 10 ounces on one side. Are you guys balancing these tires at all on DD machines or skipping it out of futility?

Love this truck badass build.

[BurbanFreek]

Originally Posted by Pietro

YIKES

x2

[Pietro]

Originally Posted by sick_sahara_yj

all mine get balanced. sometimes you get tires that are way off. when I get those, they get marked and put in a stack for offroad use only.

Not to be a pain in the ass...

Are you doing a dynamic balance with wheel weights or static using beads/BB/etc. ? If a dynamic, is it typical to use 5-10 ounces? I spun one up and it took half the rim diameter on just one side. I didn't even try the rest because I have more important things to do than lift heavy tires onto my old ass balancer. Just trying to figure out if I should even bother.