Ideal amount of lift/ground clearance for an expedition vehicle...

[nfpgasmask]

OK, so I am in the pre-planning stages of building my ultimate expedition rig. The base vehicle will be a 1990 Isuzu Trooper 5-speed. (Read, poor man's Defender 110). My vehicle choice should not be the issue of discussion here, as I have always loved the 1st generation Trooper's "box on wheels" design. I have been driving these SUVs for years, an aside from a few natural shortcomings, I feel it is an EXCELLENT economical choice for a base expedition vehicle.

The Trooper, at stock height, has a fair amount of ground clearance. Honestly speaking, you could use it out of the box to do just about anything short of really difficult trails and very steep hill climbs in loose terrain. Some of the short comings of this vehicle, in it's stock form, include weak power plants, open diffs and IFS. With my build, I will be keeping the IFS, but I will be doing an engine swap to give the vehicle more power, and I will be installing at least a rear ARB locker, and hopefully my budget will allow a front ARB as well. I will also be installing upgraded gears, going from 4.56s to 4.77s or possibly 5.38s if I can find and afford a set.

These vehicles are body on frame, and they are built quite stoutly with no structural shortcuts. The Isuzu 10 and 12 bolt axles are very beefy, and the 5-speed trans is pretty much bullet proof.

Now, I drove a 1991 for a few years, and it had a Calmini 3" lift installed. I ran 33x12.5R15 Procomp Mud Terrains. The tires are very wide and very heavy, and they didn't quite do it for me from an expedition style look and performance point of view. Three inches was a nice amount of lift, however this height put the CVs at an extreme angle. My original plan was to keep this 3" lift and move it over to the 1990, and run 255/85R16s on some new Toyota 16x7 steelies. However, with my new scratch build, I have been thinking about dropping my lift down to about a 1.5" or 2" lift, with 235/85R16s. This would not be a serious compromise in my opinion. It would take some of the angle off the CVs, and it would likely give me better fuel economy (lighter, smaller tires), and a safer center of gravity when off road.

So, I just want to get some opinions here. Is sacrificing ground clearance really something I should think over? Understand that this vehicle will be used as an expedition vehicle, NOT a rock crawler or Rubicon Trail truck. However, I want it to be as capable as possible.

Anyway, thanks for the opinions.

Bart

 

[gregm]

Glad to see that your interested in Expo. Some of your questions IHM can only be answered by you. How much, and what kind of gear are you going to carry. Roof rack or roof top tent? Both will change the vehicles COG and performance, as well as MPG. You said that you want the vehicle to be as capable as possible, so my advice would be to not use 5.38 gears with the tire sizes that you are thinking of. High engine RPM, slow road speed, and poor MPG will result. As far as the "Ideal amount of lift/clearance" I feel there is no "Ideal". Have some fun and do some Google searching, I'm sure you can find a ton of build threads and pictures for your vehicle. In short, build what you want your vehicle to be. Greg, Flexible Fabracation

 

[nfpgasmask]

Thanks for the reply. I do realize that the question is kind of ambiguous. I guess I was mainly wondering what the general consensus is. Since posting, I have pretty much decided to go with a mild lift, about 2"s, and most likely I will go with 235/85R16 or possibly 255/85R16s. The gearing will be at 4.77, which should bring the performance closer to stock with a mild lift and tires.

The vehicle will have a huge 5x6 Conferr rack, and an ARB winch bumper, etc, all the typical expo gear.

Thanks - Bart

 

[redthies]

How long is a piece of string? That's what comes to mind first, but your 2" lift and 255/85R16 choice is perfect in my world. It is all you would need/want to go 99% of places in the "real" world.

 

[expedition4x4]

Decide on the size of tires and amount of articulation you want then that feeds the decision on lift height

 

[TangoBlue]

I agree with all the input so far... it's really up to you and how convenient it is to get to your roof rack or get into the vehicle rear and side doors for loading or removing gear. I also say you may not be interested in rocky trails like the Rubicon now, but perhaps your opinion may change -- don't limit your options but deliberately plan for the future of your build/truck. Really, it depends upon your comfort and frequency in which you need to access your gear. If an overlanding stepladder is required to be affixed to the side of your truck just to get into the rear of the truck, then it may be too tall. Good luck -- sounds like a noble endeavor!

 

[ExploringNH]

As low as possible, as high as necessary.


Keep it as low as you can while getting the tire clearance you need. Decide your tires and the rest should fall into place. Different terrains, climates, and personal requirements will dictate the tires you need. Once that is figured out you will know how much lift (if any) you need.

 

[gregm]

Your getting alot of good input on this one Bart. I think your 2" lift choice is wise for that vehicle. Don't overlook the option of cut out fender flairs also. Tire clearance will do wonders for moderate lift. The next thing on the list IHO should be some sort of traction aiding diffs. You'll be amazed at the places a mildly modified rig with true locking diffs can go. Some people get excited about the cost of lockers, but if you are changing gears anyway why not wait until you can do it all for one setup charge. You work in the industry so you know alot of this stuff aint cheap. Spend smart young Jedi. You also mentioned
that you are thinking about an ARB bumper. Are you planning on a winch also? The reason I mention this is though they are a great bumper they are also HEAVVVVVVY. Ever look at pre runner tube bumpers? Just throwin out ideas. Just don't forget as you plan out your build that if done right this thing can take you from the Mojave Road to Black Bear Pass and countless canyons along the way.

 

[bansil]

I'm bias'd :sombrero:
I would keep her low,get a set of rear shackles with a distance of 6-1/2 between holes, run 3/4 in bolts with nylocks(don't bend the shackles)

this will let you crank the front about 2" which will be a big difference under the crossmembers.

Save up for a new set of springs because your stock ones are going to go flat rather quickly using them with any extra wt.

Save up and put lockers front and rear,that with 4.77's,the trooper will be a tank.

If you go with the unicorn 5.38's do not use the included ring gear spacer, find an old rear 10 bolt(and steal the carrier for use in the front of your trooper.(or go with the rear 10 bolt application ARB air locker.) these gears were originally made for the rear 10 bolt not the front

255/265 tires are a good match just make sure wheel offset will keep tire out of the frame at full lock, you may need to trim/grind the front body mounts behind bumper

 

[t4rman]

I have a +3 Old Man Emu Lift with 32' tires on my 4Runner. Has proven to be more than enough. I would do 2 inches or less if I were to do it again.

 

[Buliwyf]

For me, the perfect setup for a fullsize truck is just a 2" leveling kit on a f350. Maybe 1" more in the rear is nice for some people. 33-34" tires. Oil pan and transmission skid plates. For smaller SUV's and Jeeps, I've had the best luck with 2"-4" setups and 33" tires. Pretty safe bet that's all you need to cross South or North America, Australia, and Africa.

For me, anything beyond 33" tires puts a vehicle into "playtoy" use. Not practical travel and work use.

Nothing too crazy. The huge lifted fullsize trucks often do everything worse than the mild trucks, and the benifits of the huge lifts are never realized due to not having trails big enough for that type of truck. 4" lift and 38" tires are the most I've seen on a working truck, that actually worked well.

I often actually LIMIT flex with airsprings when I'm on a trip where I'm loaded or have a camper or trailer. The airbags are easy to remove if I need my flex back. (rare)

 

[nfpgasmask]

Thanks, guys for the opinions. I think right now the only remaining dilemma I have is if I go with 235/85R16s or 255/85R16s. Here is a complete list of the planned options from the frame up:

OME Front and Rear Shocks
OME Rear Leaf Springs
Calmini HD Torsion Bars
Calmini Upper Control Arms
Calmini rear leaf shackles (if needed)
Front Torsion bar crank
Indy 4x HD Tie Rods
4.77 10 and 12 bolt gears with
ARB Front and Rear air lockers
Isuzu MUA5-speed gearbox
GM 3.4 HT Crate Motor
Toyota 16x7 Steel Wheels
235/85R16s or 255/85R16s (either BFG or Toyo MTs, have not decided yet)
ARB Winch bumper
Warm M8000 Winch
Rock sliders
Indy4x Rear door ladder
Confer (5'x6') Roof Rack
1990 Trooper LS body with full respray inside and out, custom interior

The stuff in bold is the stuff I still have yet to purchase. Everything else is sitting in the garage ready to go.

I will admit that part of what I love about this build is building it with all the rare vintage parts (Confer rack, ARB bumper, the 90 body, etc.) but I also want it to be capable and fulfill my needs as well. I think I am on the right track, and I thank you all for your opinions on the lift amount. I just need to decide about tires. The 235s will be skinnier and the diameter will be about an inch or so less than the 255s. Which might be a good choice however I think the 255s will be better because I think they can handle a heavier gross weight. I have to look into that.

My main reason for considering a sacrifice in lift, is gas mileage and the idea of keeping my CV shafts at a more normal angle. As I said before, I don't like body lifts and I don't plan on hard core rock crawling with this Trooper.

Thanks,

Bart