SOA project for 86 GW-ALL ADVISE APPRECIATED!!

[Oracle]

(Deep Breath)
Okey guys, I'm going to bite the big one and go for this. Here's the setup.
86GW stock everything. 139k on odo; D44 front, AMC20 rear.
Have towing package so 3.31's. open carriers.
Plan to keep AC, go with 4barrel and manifold. Engine has been rebuilt, less than 50 miles ago(or so i'm told heheh). Stock Springs look strong, no squat at all. Condition of underbody and rear cargo area show little or NO carrying of anything heavy, Zip evidence of any kind of off road activity. Car has sat for a year. and ...
(drumroll...) NO RUST anywhere.

Here's where I want to get to: Trailready by Ouray. Function of vehicle, 60/40 off/onroad. Capable of comfortable down the highway lonnnnnnng trip (i.e. to Ouray and back) and "competent" trailhandling i.e. class 3/4 trails, forget the class 5 "what do you have to drive now that you've busted your truck?" stuff.
In other words I want to be able to follow you big time rock thrashers and then go around the sections you want to play/break on smile.gif heheheh.

Current thinking is this:
SOA, with RBbeast's Shack kit in back.
Part's Mike's flattop knuckle and high steering kits; little holley 4160 600cfm (option to go to 750cfm 4barrel, on adapter on stock manifold. (looking for motor to develop good torque and mileage, won't ever see over 4700 rpm)
Either the new electric lockers front and rear, or detroit soft lock rear, electric front, Milemarker hubs, modified driveshafts with high angle cv joints/hd u-joints/ubolts as opposed to the straps;

Planning to run stock rims with 33x9.50's cause of relatively light weight ergo lower rotating mass, as compared to the 33x12.50's 13.50's and 35's out there; I think with careful attention to custom bumpers/skids etc. these will get me enough diameter to get over most of what I want without overtaxing brakes, springs/steering etc. lower mass means lower stress seems to me. Question? what recs does anyone running 33's have for gearing? should I pull the 3.31's and go to 4.10/s from the get go? or wait till I see how the 3.31's work first? are there carrier issues on going over 3.73's?

Going with a confer type roof rack, spare will ride up there, so can get some kind of aux tank under rear but not too big as I want to maximize clearance for rear exit angles and just supplement existing tank.

Also going to either find or build an aussie bullbar type front bumper with integrated receiver/skid plate and corresponding rear bumber with similar receiver/skid-both to maximize entry/exit angles and provide ability to skid over things without hanging up. Some armor on the diffs, some additional skids underneath, and somekind of "rock rail" skids along the frame rails should solve any problems I'm likely to encounter.

Ok, guys, have at it on specific recs/ do's don'ts and "things I would've done different if I had known". Want this sucker ready to romp by Ouray.
oh, as to cost? LOL, I've already decided this truck will be painted "Blood" red...ergo only one good name smile.gif "BloodSucker" LOL.
Oracle

[jode]

You asked for it...
I think 9.5" wide tires on a huge, lifted truck with 33" will look LAME. Aside from looks, why not go to a wider tire? Skinny tires are better in mud (sometimes) if they can sink through to the bottom, but they really can't touch a wider tires footprint for getting traction in most other situations. I don’t think that the larger width of the tire will cause (much) more stress than a thin one other than that it will hook up where the 9.5” will slip. I guess that will save drivetrain stress, but that ain’t exactly the type of thing most people want offroad.
As far as a SOA and Riverbeast kit...A-OK i fully endorse it and I think that is the only way to do it.
As far as axle gearing...I say put on the tires first and see how it works, then you can decide to keep it or not and THEN get the lockers.

[Oracle]

Jode, take a look at bob barry's 33x9.5's on his cherokee. they aren't as skinny as you might think and he LIVES in the rocks. And, depending on how much ACTUAL lift the soa gives me, I 'might' even step up to 34x10's. My conclusions from my years in 4 plus areas, including moab, is that the fundamental issue is one of wheelbase, tire diameter and tread, not so much width.

Wide works on 1. sand, 2. snow on a LIGHT 4wd (i.e NOT a fsj)and that's about it.

Excepting the really RADICAL rock climbing that people do just for show (that's not my cup of tea) in the 'real' wilderness......unless you drive FLAT rocks, if you look close, the contact patch is almost ALWAYS substantially thinner than the tread width on the 13" and wider treads, usually a matter of 4 to 6 inches wide. The trick is to get the flat part of the tire tread flat on the rock, this is very hard to do if you're crawling round rocks with wide tires, UNLESS, 1. you have radials AND are SERIOUSLY aired down in which case what you usually get is cut sidewalls lowered diff ground clearance and huge jamming forces between rocks which usually result in busted ujoints (if you're lucky) and busted axles, drag links, twisted driveshafts or ripped axle flanges etc. if you aren't. IMHO and experience, what climbs rocks/ trees, knobby dirt mounds etc. is rolling diameter.

Think of it this way. the ground doesn't know anything but the tire that touches it. It feels the tread design, the tread compound, the siping or lack thereof, the width and length of the contact patch, and, the weight sitting on that tread. All of those things determine the 'friction' the ground sees, anything above that, suspension, engine, transmission, paint , cute girl in the passenger seat etc. the ground never sees.... smile.gif

One thing that anyone who has driven them will acknowledge, huge tires do better, but the major reason is diameter, not width. BUT here's the tradeoff.
Huge wide tires weigh a HELL of a lot more than the same diameter thinner tires. This extra 'mass' creates an vicious circle of stress thus needing stronger brakes, stronger running gear, stronger steering needs, more steering damping, stronger engine, stronger transmission, stronger transfer case etc. each of which adds WEIGHT, which institutes another round of needing more everything. This all combines to kill any kind of fuel efficiency etc.

Add to the above the design of the narrow track GW and the lift necessary to get 33x12.5's or bigger in there with adequate articulation clearance puts me way above where I want to be for sidehill/off camber trail crawling not to mention tooling down the road on the way to the trail. I'm looking for the best compromise 'fit' between optimum tire height, with lowest possible cg. Because of the narrow design and limited wheelwells, In a GW I can go inches higher with a 9.5 than with a 12.50 or wider tire given the same lift. sooo there you go. smile.gif

there's a lot of math/physics here that can explain what I'm talking about but take my word for it, the principle is the one of the lever arm equating to the radius of the tire.

As a practical matter, in my mucho years off road, I've seen suzuki's on stock tires scamper up stuff that 50 k custom big tire rigs fell off of leaving spit ujoints, axles, transfer cases, and blown trannies strewn all over the trail. I have hours and hours of video of that stuff. More to the point, I've seen locked moderate rigs that never broke running the same kind of 4 plus rough stuff. And, I'm not entirely alone in my thinking. When Dick Currie (of axle fame) used to drive Moab in his own rig...well, heheh you'd have been surprised at his choices. When we opened the Golden Spike waaaaaayyyy back, he was in his skinny tired, Ford 9" custom locked axled wrangler, and I? well heheh I was in a stock 4 banger Isuzu Trooper with 31x10.50s and open axles. (I wouldn't recommend that by the way)with a pair of hand built turning brakes.
Anyway, I hope I've explained the reason for the tire choice.

[jode]

Obviously there are different opinions out there.
The weight thing and the Samarai issue are basically fact, but if you think you are driving a Samarai-weight vehicle just because you don't add the extra weight of a few more inches thickness, then you better reconglomerate. Physics will tell you that the more tire you have on the ground, the better. You have a good point with the fact that there isn't always 12.5" worth of good traction available, but maybe you should realize that even though you have millions of years of offroad experience, there are other opinions out there...and you asked for them if I recall correctly.
About the physics of a taller tire giving a better lever and all that ...sure, and if it takes a thin tire to get you your taller tire
then, by all means, go for it. IMHO cut out your fender wells and stick the bigger tires in. However, like you said, if you want better gas mileage, then go for the skinnies...but I still think it will look lame.

By the way, take it easy....you asked for opinions...right?
:D

[Josh D]

Oracle,

I think I agree with Jode on this one (even though we don't agree on shims :D ). From what I've seen (especially in Moab) is a skinnier tire in front when climbing rocks tends to 'crab' to the side due to less contact area. You can also air down a wider tire more. On the street, the wider tire will last longer due to load distribution. There are conditions where a tall skinny is better, but rocks is not one of them.

Josh

[jode]

Thanks JD...you'll come around on the shims issue soon enough too ;)
BTW I am serious that my bud was driving around with 16d nails as shims
:eek:
Oracle, I can see your point about the tire not fitting where you want to put it if it is too wide, but most of the time when I go wheelin, that is not the most pressing issue. You are right about Moab, though...the more on the ground, the better.

[Stuka]

I run 30x7's in the winter. They dont look bad at all. And a skinny tire can provide a LOT better traction in some areas compaired to a wide tire.

[2j20's]

WOW Oracle I think you took one more then one deep breath's there !. I THINK YOU POINT WAS WELL PUT !. and sounds like you are seriously in for working you rear end OFF to get all that done ! by ouray. But from what i gather from meeting you ! you have the drive to do it!.I think a 750 carb is to much for stock.I think the lockers would be nice to have. This is the same route i want to take on my extended j20.GOOD LUCK ;)

[Oracle]

Jode, wasn't getting personal, just explaining in detail my thinking on the tires. Please don't misunderstand. smile.gif
J20's -yeah, a ton of work to do, maybe my biggest issue is what kind of gearing I'm going to need for the 33's. I'm thinking 3.31's are going to suck LOL, but seems I ran across something that said without going to a different carrier, I wasn't going over 3.54 or 3.73s.
Got it back to ranch yesterday, put it up on blocks today just in time for major storm LOL.

Any one with soa exp please let me hear from you about the 'watch its' and the 'gotcha's

[2j20's]

I have the 373 and i like them with with 33s.

[liliysdad]

the dana 44 carrier break is indeed 3.73

[Oracle]

Lil'sdad? Is it also the break for the AMC20 I got running in back? thanks smile.gif

[liliysdad]

i researched and the carier break for the 20 is 3.08 so you are good to go. a carrier for the 44 is only about 60.00, so it shouldn't be too prohibitive to go a little deeper if you want.

[Oracle]

sweet! so I can go 4.10's if I need too. Thanks a bunch smile.gif

[Rockwagon]

My two sense change all the spring eye bushings while your at it exspecialy at the front shackles. 33's + 331's no prob. I wheeled for a couple of years on 36's and 331's. I never had a problem make my waggy move.

[RustyJeep]

I have 4:10's with my 33's and in my opinion, it's just the perfect mix between low RPM cruiser and high torque off roader.

[River Beast]

I haven't got the time to answer this right now.... but I will.. I promise :D

[jhatcher]

Oracle could you please expand on your sentence

"One thing that anyone who has driven them will acknowledge, huge tires do better, but the major reason is diameter, not width. "

What I ASSUMED about the differences:

An increase in diameter gives you more ground clearance and a longer distance of travel per wheel rotation.

A wider tire gives you more stability, wider contact pattern to ground, but increased width so tighter trails may be a problem.

Thanks
Joseph

[River Beast]

Ok... <yawn> ;)

Sounds like you got your work cut out for yourself for the next 3 months! :D GOOD!!! haha

This is the way I look at it:

COG (center of gravity) increases with lift... so the wider you go with rims/tires it compensates...."go up... go out" so it will offset or lower your COG a bit. I like the wider contact patch.


SOA's are not hard, just time consuming. The biggest part of the SOA up front is proper placement and position on the front axle...why... one perch is on the axle tube, the other is on the diff housing (cast iron). This requires a bit of knowledge in welding. The most important aspect is making sure the perches are level, or equal distance from the TOP OF THE AXLE TUBE. This will require grinding the cast a bit and shaping the new perch to fit on top of the cast housing where the perch will sit. If they are not equal distance, your rig will lean to the driver's side. Also you will need to grind grooves on the bottom of the housing for the U-bolts, since they are inverted for the SOA.

IF you use stock springs you really don't have to worry about rotating the pinion up at all... so you can weld the perches on parallel to the OEM perches...even if you weld them parallel and feel you need to angle it up some, you can buy shims to angle it up, but don't go over 3 degrees... it will severely affect the steering geometry.

The rest of the front fabs are a cake-walk...brakelines can be replaced with 77 GM 1/2 lines that are 19" long and $20 ea at Autozone..or you can fab some drop brackets for the OEM lines. A 4" drop pitman arm will help with the draglink and bump steer issues will be a minimum. Shock will have to be replaced with longer ones.

My rear shackle inversion kit is a completely bolt-on kit that required a 4" angle grinder to remove some metal supports, a drill and common hand tools. My kit gives 7" of lift for the rear to compensate for the SOA up front and you don't need blocks either (I HATE BLOCKS). The added benefit of my kit is the extra droop you get out of the rear since the shackle is now inverted.

The other mods that are required for install of the rear kit are relocation of the E-brake hardline thru the next rearward hole in the frame, longer shocks and/or relocation of the mounts (may not be necessary to relocate) and extended rear brakeline.

[Oracle]

Jhatcher, regarding my "huge" tire statement, Think of climbing a rock as equivalent to trying to lift the axle the height of the rock and the radius of the tire as the length of the jack handle you have to work with-more radius, easier to lift. This is the major advantage of Huge tires in dry, high traction situations. Next issue is friction. Huge Tire will have greater contact patch IF it is flexible enough to conform to the available contact area, i.e. sand, snow, mud, and things that are flat and parallel to the tire's tread. Rock walls/waterfalls, faces and slickrock are often that flat. Normal rocks that you drive over in the course of trail riding are not, so the effective contact patch of the tire is often substantially less than the tread width would lead you to believe. When dealing with flotation (i.e. sand, deep mud,) the principle is different. Here you're trying to surf across before you sink. What comes into play here is Newton's "for every action there is an opposite and equal reaction" principle. ROUGHLY speaking, the force driving you forward is proportional to how much mud /sand your tires can throw out behind you, ergo paddled tires for the dunes and cleats for the mud. If you're crossing "trail" mud, more often than not the tall narrow tire under the heavy vehicle (assuming suitable tread) will work its way down to something more grippable and move you through when a lot of high flotation tired rigs will spin uselessly. I've seen guys park their monster tire rigs on slightly off cambered muddy roads in southern Utah (stuff is claylike), lean against the truck and have the truck just start sliding sideways till it finds a rut or smacks into the downhill side. scary stuff. As for snow, think of a snowboard vs. a set of ski's. Sidehills in snow on flotation tires are even scarier as the downslope snow hides what's waiting for you.

[Oracle]

RiverBeast, thanks for the post smile.gif Couple of other questions:
1.Most SOA's I've read about in the archives seem to have netted 5 to 6 inches max. How do you figure 7?
2.What gear ratio's did you experiment with when you had 33's and which did you feel gave you the best all around compromise for highway vs. trail?

Note: Since the GW has an auto, I can get away with a lower numerical ratio than a stick for 'crawling'and playing in the rock gardens is not what this truck is intended for.
3. Given that I expect 5 to 7 of lift from the soa and your kit, How much steering modification do you think would be necessary? One flat top knuckle and an angled drag? or go full hog with both and get the high cross steering and be done with it?

Lastly, I hear what you're saying about the wider tire for stability given the change in cg. I was hoping to modify(lengthen and make adjustable) the axle locator bars and antisway bars using disconnects for the latter off road. Since you're something like 14" up, I realize that's not a consideration for your rig, but I'd like to hear from anyone else with a six " or so lift that modified and kept them /or not and why.
thankx

[River Beast]

<blockquote>quote:</font><hr>Originally posted by Oracle:
RiverBeast, thanks for the post smile.gif Couple of other questions:
1.Most SOA's I've read about in the archives seem to have netted 5 to 6 inches max. How do you figure 7?

2.What gear ratio's did you experiment with when you had 33's and which did you feel gave you the best all around compromise for highway vs. trail?

Note: Since the GW has an auto, I can get away with a lower numerical ratio than a stick for 'crawling'and playing in the rock gardens is not what this truck is intended for.
3. Given that I expect 5 to 7 of lift from the soa and your kit, How much steering modification do you think would be necessary? One flat top knuckle and an angled drag? or go full hog with both and get the high cross steering and be done with it?

Lastly, I hear what you're saying about the wider tire for stability given the change in cg. I was hoping to modify(lengthen and make adjustable) the axle locator bars and antisway bars using disconnects for the latter off road. Since you're something like 14" up, I realize that's not a consideration for your rig, but I'd like to hear from anyone else with a six " or so lift that modified and kept them /or not and why.
thankx<hr></blockquote>

Ans. #1. Dana 44's are 3" at the axle tubes plus the height of OEM perch and height of spring pack PLUS height of NEW perch... When I did mine... the the difference in measurements was 7".. you gain the distance from mount to mount PLUS spring pack width.

Ans. #2. I ran 33x12.50's on 15x10's with 4" Skyjacker, 3" bodylift and 3.54's... I spent alot of time in lo range on the trails... off the line was doggish and inclines seems to be a hinderance in my book... 4.11's would be a GREAT choice for 33's

Ans. #3. Ok... if you are using stock springs, you can get away with a 4" drop pitman arm. If you want to move everything up above the springs... get Part's Mike High Steer knuckles and move it... I would go with the 4" DPA first $70 vice $400... worth the savings to see if it's what you want.


As far as swaybars and trackbars go... not needed in my opinion.

The sway bars limit articulation IN A BIG WAY... not good for off-camber trailing...especially if you don't have lockers. You can make longer swaybar links that can be disconnected for trails... not too hard of a fix there. IF removed, a slight roll will be felt around corners, but these are not sports cars in the first place.... mine never had swaybars or track bars...my 79 K5 did... I removed them and got LOT's of bodyroll in corners... but that's cuz I was 'USED TO IT' ahandling with swaybars... it only took a week to get re-aquainted.

Try taking it off now or disconnecting and tieit up out of the way and get a 'feel' ro it without.

Trackbars are mainly needed for coil-sprung vehicles, not leaf-sprung... it's intended to hold the asle straight under the frame.... leaf springs are mount in 4 locations almost in equal distance from axles and provide ample lateral stability.