Im thinking aboot putting big rubber on modified ifs system. I dont want or need a lift, nofenderwels fiberglass fenders and tub in the rear also not afraid of a bodysaw. I just want to know if the ifs system would try and inplode with 37x12.5r16" tires. Iwill be changing the gearing to 4:88 also new carrier and half shafts heavydudy balljoints that sort of thing. i dont have it in 4 wheel that much i drive fast in sand snow dirt. baja PreRunner stuff is more my type of wheeling. but my new baby is a 93 k2500(8lug) Burb and i dont really have time, cash or desire to build a 2wheel from it. Part of my job is pulling 7,200 to 18,000LBS boats up wet/sandy/scummy ramps and a locker in a 2wd can be very tricky at times eaven with a winch. i am very convinced that driving is 90% skil/experince/feel and 8% gearing/rubber the other 2 thats just plain luck. I get "Great" milage with it now 19.6(no crap hanging off the back) she has 321,842clicks on her and has developed WEAK VALVESPRINGS.
the motor is geting a lot of work as well as the rest of the truck befor spring.
im trying to spend under 10,000$ on the build I havent orderd any thing yet! but soon the ups man will hate me.
Thanks, Dustin Pares

The literature I've reviewed consistently states that one ton IFS is good with moderate wheeling to 33" tires. Of course the H2 runs 35s on one ton IFS, so I think 35s are realistic. 37s are probably pushing it.

My humble opinion would be to replace all the ball joints with MOOG parts and upgrade the tie rods with something like this:

http://bulletproofsteering.com/gmifstierod.html

The factory tie rods on the OBS are a little beefier than the NBS, but they could still use some help.

Buy a set of CV half shafts with a lifetime warranty as spares, and learn how to replace them efficiently. You'll probably hear a lot of smack by even mentioning IFS on this board, but I think you can do this with 35s.

Go with flat Control Arm angles and upgrade ALL of your suspension joints.

the font hurts my eyes

yeah sorry aboot size of font.
thanks for the advice and that link, but i was thinking i make some thing up for all the likages perhaps if i find some extra time/funds ill getrid of those dumbass torsionbars.
and thanks for not instantly flaming me for not hateing ifs its not all bad look at some 2wd prerunners 20inches of travle isnt uncommen in most of them and some have way more, you cant say that that isnt cool!

Being an IFS Chevy owner and engimineer I to was very curious about this question about five years ago. I had run some mild calcs and it seemed that the factors of safety would definately be exceeded with anything over a 35. Alas I was successful in convinicing noone of my findings. Everyone ran a 6" suspension and 3" body and 38's. Until oneday at pismo I came over a dune to find a 3/4 ton surburban just chillin at the bottom. I drove around the drivers side and low and behold with a whiplash 14" lift and 38's he had managed to take his driver side tire and fold it underneith the transfercase. In the process breaking every front end component on that side.
So my advise is stick to the facts. Run a not so heavy 35 max and realise that you are working with an FOS between .9 and 1.0 when wheeling. And get ready to lube and replace ball joints cause they dont last very long with moderate use or huge heavy tires.

my .02 as usual

the episode where they built a mid 80's blazer in to a pikes peek race truck
it was a ford ranger front end all the baja rangers run 37's so do the 2wd chevys. im not worried about the mounts as there are thousands or baja clones running 37inches of rubber on the street and in the air, and thats all hanging on fabteck or CST 2wd kits without a problam. i think that perhaps poeple should pull there heads out of there asses and not build/buy 14inch lifts its not eaven a 14inch lift there dropbrackets with painted or worse yet crome a arms that are useing the stock size suspension componentry. and not think that they need more stoping, going, and steering power.
im not trying to ofend any one here or anywhere that has a "small dick BIG TRUCK" complex im just saying that yes i under stand that stock balljoints, steering, and any number of things need to be taken care of when playing around with bigger and in most cases better tires or motors or any other componet of the system that is a truck. what i dont quite understand is how a 2wd 1/2 ton rig can run something that a 4wd 3/4 or 1 ton rig can not. and i missing that part of my brain that can figer this type of thing out or did gm rely screw the poch big time on it last 20 years of building great trucks makeing the 4wd drive-train so much worse that it weakens the rest of the truck to the point that its practicly unsafe when left as stock muchless moded to hell.
i under stand that there are limits to the streath of certan things like axle shafts, im happy with the thought of 35" tires but as you said the h2's are comming from the factory with 35"tires so what happend to #1 the gm safetymargen and #2 the "aftermarkets" ability to help stupid poeple like me out. i just cant exceped that in order for a 4x4 rig to be durable it must use solid axle setups that came out in the 60's and dont eaven get me sarted on fords Twin Tracsion Beam bulshit.
so now that im done with my hissyfit.
What should i do...
A;cut and weild untill i have a RANG~BURBAN.
or
B; sell it and buy a 2wd and use the CDL rigs for pulling work(by the way there rear wheel drive also)

thanks again i just needed to get that off my chest
Dustin
Pares

Well You have severaly option out there unfortunately most require extensive fabriction and modification. Their isn't a lot of "bolt on support for you" CST and several other companies build long travel high strength IFS kits that replace everything underneith the front end. If you are desert racing or jumping, These systems are very strong and and durable but very costly.
These systems also convert your truck over to coilovers up front instead of torsion bars.
Now the reason the 2wd are better suited for lifting high an making long travel is the complete absence of front end components. 2wd 's have A arms ball joints and knuckles. Plus they "freewheel" and dont turn with engine power, thus reducing the torsional forces applied to each wheel up front. So when lifted high and in extreme situations you need not worry about axle shaft binding or geometry throughout the range of front end travel.

Now the IFS 4wd sux because it was designed around an ultra lame torsion bar setup in which you essentially have a really long bar that is torsionally preloaded and attached to the a Arm acting as a spring. This severly limits the amount of front travel due to the fact that in order for the truck to "flex" the bar physically has to turn at the a-arm end while staying fixed at the crossmember end. Now this equates to an excellent ride but terrible for off road. As such the axle shafts, tie rods and knuckle assemblies were designed around this limiting factor.

When you put huge tires on an IFS 4wd what happens is you not only increase the rotating mass, you increase the moment around the torsion bar, causing a much higher torisonal loads in offroad situations. This ultimatley leads to torsion bar fatigue or shearing which leaves the front end unsuspended and it fails.

Many companies to combat this in the '99 and newer trucks have realised the need for a 4x4 to actually perform offroad. www.Rockkrawler.com has made coilover conversion kits that are essentially bolt on and allow up to 14" of wheel travel. Pro comp makes a similar kit for the 2000 and up F150's, but as of yet I havent seen anything for the 88-98 CHevy IFS.

hope this helps.

so if i wher to build some new longer, heavyduty domtube A~ARMS, make something simaler to a motor cage to hold a set of big coils and shocks and find some company to build some superstrong halfshafts and throw some limiting straps on. then all i would need to worry about is tearing my thirdmember in half, Right? that doesnt seem so bad.
Thanks
Dustin
Pares

Paragraphs are your friend :shaking:

so if i wher to build some new longer, heavyduty domtube A~ARMS, make something simaler to a motor cage to hold a set of big coils and shocks and find some company to build some superstrong halfshafts and throw some limiting straps on. then all i would need to worry about is tearing my thirdmember in half, Right? that doesnt seem so bad.
Thanks
Dustin
Pares

Yeah.......Pretty much. Thats why most people SAS its just easier and proven. If we owned Toyotas their are tons of long travel front kits. Oh well.:( :beer: