upgrading suspensions for a noobie

[raser13]

thanks guys, this is the kind of info i needed. i didn't think there was much between 33s and 35s. my 31s have done me a great service. i was figuring that the larger diameter tires would make it easier to traverse the lager rocks and crevasses. and for the coil spring set up. most of the folks here are running them. figured there was something to them. that's why i'm here asking questions. if my current jeep is good enough to try to run this type of terrain i'm also good with that. i just don't want to drive a few states away to have fun. and come limping off the trail because i didn't do my prep work.

i'll check out the books out on amazon and start doing my home work so i can come back with more targeted questions. i guess my best questions to ask now is if any of you are in the southwest area or the Colorado area. what are you running? and what does it take to traverse your area. i would assume Colorado is close to Missouri terrain. just a bit more up and down.

i've been in the deserts of el paso tx when i was stationed there in the army. the humvees did great in the sand. and i figured my jeep would to. but i never really got to play up in the mountainous areas. so i really have no frame of reference. well you tube videos of these really over powered rigs that have like 10K worth of bolt ons. so i really don't know what it takes. i figured i would at least need to upgrade the suspension. but i will figure out all of my gear ratios and add them all to my stats. and come back so i can be better tuttled by the masters. thank you all for the info and for the knowledge of what i need to know so i can supply you with so we can figure this out together.

 

[Peanut Butter]

You can do alot with 31" tires but if you want to go bigger go only 1 or 2 sizes then you will look like this

This is what you'll run into in Colorado on the really tuff trails you might try. Most of the places you go are going to be lots of loose rock, streams, and some larger rock for a short distance. Anything else and you need to stay away to start with. Your best bet is to always wheel with someone else, especially in Colorado. Just the fact that the weather can change from a nice sunny day to snow in a few minutes warrants a buddy with another 4x4.

33" tire at the most, good beefy u joints, one piece axles, axle housing mods for the AMC20 , at least one locker, good roll cage, winch, power steering, Transfer Case mods, skid plates, and the necessary equipment to spend the night in any kind of weather.

That should help you get you list started. By the way, coil springs allow for greater articulation than leaf springs, but that is a major modification. Having good common sense is going to get you father on the trails than anything you can do to your Jeep. There are trials you don't need to try till you have mastered the more common ones. These other trails almost always demand you have a buddy with you. Moral of this story: start small and work your way up, building you dream Jeep as you go.

 

[gr8dain]

You got a lot of great advice. I am just at the point of wheeling my CJ (frame swap done over the winter and just getting her tires dirty). I have been part of a local club for a number of years and this is invaluable. A lot of experience with these folks and they are happy to talk about it.

Some of what I have learned is: learn how to drive the tuff stuff on a stock or slightly modified rig and you will learn more than you ever will in a heavily modified rig that can basically take the obstacles without effort.

Not all tires are the same. Do your research here. Know what you want to do. And keep in mind the amount of street driving the Jeep will still see. And not all 33s are really 33. The same is true for all sizes. Some 33s really measure out to 31.5. Some 35s are really just over 33. So talk to people who have and use the tires you are researching.

Personally, I just went from stock 2.73 gears to 3.31. Not a big jump but as the Jeep is my daily driver I am happy with it. I am only on 31s. But those tires and the 2.73 made for a sluggish drive. I can now accelerate. If I had gone with any lower gears, I would think that I would want a 5th gear (which I don't have). So again, if you are going with a dedicated trail rig now, going with 4.10s on 33s may be a nice combo for you.

I was on a nice green/blue trail a few weeks ago. I tried an obstacle that would have been easy if I had lockers (or at least a rear) but I am open/open right now. I tried it from a few angles and eventually chose to go around it. Basically, being open made me have to think harder about it and watch my line better.

When my tires need replacing, I think I will stay below 33 as going up further will push me for new gears. And I am not going to be ready for that expense yet.

I hope I provided some valuable responses.

 

[Posi]

You can have a great time and hit some challenging obstacles with a stock Jeep in CO.
Most all tires 38" or under are not what they say.
My 37" MTR measure 35" with 20psi, guessing 32"-33" aired down.
In your case I would recommend 33" with 2.5 lift, numerically higher gears, recovery gear, and first aide kit.
Run the 33" until the rubber wears out, gain experience, and most of all have fun!

Side note, the pics of the Jeeps you posted all have linked suspension, (the yota has rear leafs). If you want that kind of flex with leaf springs you would have to go spring over which I wouldn't recommend to you at this point.
Also, I was a passenger in a CJ that had flopped, the engine was still running and had to be turned off. Although not as good as FI the MC21OO, when tuned correctly, is a very good offroad carb.

 

[Lumpy Grits]

Raser, I run 33-12:50X15 BFG/AT's and love'em. They have very good tread life(if the tire 'lives' that long),very quiet and fantastic traction in everydangthing.
That's what's on my Jeep in the picture.
I run these on 8" wide Alcoa rims.
Run'em at 24-26 psi on the street. 13-14 psi in the dirt/rocks and 9-10 in the sand.
LG

 

[gr8dain]

I run 31 BFG AT and love mine. I plan to use the same ones in 32s next

 

[Neuner]

I think you're in the right place for learning and putting together a solid plan and vehicle. Lots of guys on here with a whole lot of valuable experience. Possibly reading Pirate4x4 sometimes on what not to do - 'hold my beer and watch this!'

I myself am a fan of LCG and soft springs.

I had an XJ that was only slightly modified. PO had installed decent underbody armor and I put on an OME 2.5" lift with BFG AT 31s. Removed rear sway bar and put disconnects on the front. It did great as my lone vehicle and DD but I'd occasionally tag alone with some of my hardcore friends. Although I had a very basic setup, even without lockers, they could not believe how I could hook up and make it through some of the places they drug me. OEM is coil up front with leaf in the rear. The articulation was awesome with mostly drop and the soft springs kept the pressure on the tires more equal. Ran the tires at about 10-15psi. As LG noted, line is important.

With my CJ, I have BFG AT 33s with a PO installed RE HD 4.5" lift. Rest is pretty much OEM. Springs are stiff enough that I don't need sway bars. It only acts as a DD and would most likely embarrass itself in rough terrain. If I were going to head for trails, I'd be looking at similar terrain and obstacles as you are. With my ride, I'd definitely drop it with softer springs and modify the fenders if I had to. Thing has too much high center of gravity. I'd add belly armor, get at least a rear locker, change R&P, swap rear axle assembly, install power brakes and possibly add to the roll bar to get started.

You're in a great area. Mark Twain Park, Land Between the Lakes in KY and areas around Rolla were some of our stomping grounds.

 

[Bill D]

You can have a great time and hit some challenging obstacles with a stock Jeep in CO.
Most all tires 38" or under are not what they say.
My 37" MTR measure 35" with 20psi, guessing 32"-33" aired down.
In your case I would recommend 33" with 2.5 lift, numerically higher gears, recovery gear, and first aide kit.
Run the 33" until the rubber wears out, gain experience, and most of all have fun!

Side note, the pics of the Jeeps you posted all have linked suspension, (the yota has rear leafs). If you want that kind of flex with leaf springs you would have to go spring over which I wouldn't recommend to you at this point.
Also, I was a passenger in a CJ that had flopped, the engine was still running and had to be turned off. Although not as good as FI the MC21OO, when tuned correctly, is a very good offroad carb.

I was about where you are a couple of years ago when I bought a 1980 CJ5 with a 1" body lift and about a 2 1/2" suspension lift. It had 33" X 12.5 odd brand tires on it which served me pretty well until I ruined one on Old Stage Road. I bought a set of five BFG 33" X 12.5 AT's and like them a lot. I live in Colorado Springs and anywhere to the west is good four wheeling. Last summer, my wife and I did the 5th annual Colorado CJ trail ride. My Jeep was a pretty stock critter with a 256 cid engine (naturally aspirated), T-176 Transmission , Dana 300 transfer, and 3:07 differential gearing with a Jeep furnished Limited slip in the rear. My experience was as follows:
The AMC 258 i6 / 4.2l liter engine is as good as you can get for the money and the T-176 is a pretty darned good medium duty Transmission . The 3:07 gearing in the axles is great out on the highway but not so much so in rocks. (And going down Black Bear Pass while riding one's brakes is something I swore I would not be caught doing in the future.) The AMC rear differential isn't that bad if a few mods are done to it - converting the two piece axles to one piece and welding the axle tubes solid. The Jeep Limited slip is something that I wanted rid of at the earliest opportunity. I'm also in the process of regearing the Dana 300 to 4:1. That ought to slow this sucker down on steep downgrades and with the 3:07 gears give me an alternative "Overdrive ". It should also make this beast a better rock crawler. The ARB locker in the back won't hurt much either and I plan to put one in the front sometime in the future.

I want fuel injection and will do the deed sometime but I haven't had that much problems from my carb so far.

In closing, I would accept advice from just about anybody on this forum but especially from Posi. I have had an opportunity to observe his expertise first hand. His advice is "first rate". I have also learned that doing things to a Jeep "on the cheap" isn't cheap. You soon will have way more invested than you ever thought you would.

Good Luck!

Bill D

 

[Lumpy Grits]

Well said Bill D.
BTW-You're so 'rite' about the 4:1 re-gear for the D/300. It's one of the best mods I have done to my Jeep in the 31+ years of ownership..
LG

 

[Bill D]

Well said Bill D.
BTW-You're so 'rite' about the 4:1 re-gear for the D/300. It's one of the best mods I have done to my Jeep in the 31+ years of ownership..
LG

I forgot to add, a heavier, more extensive cage around the occupants is a REAL good idea if you plan to do ANY rock crawling. I plan to invest in one ASAP.

It's only money, you know.

Bill D

 

[Lumpy Grits]

Installed a full cage in mine 28+ years ago. Lot of fitting work-Well worth it.
Tied into the OEM bar and added supports under the front loop that tie into the frame.
Used 2"OD, .120 wall, DOM 4140.
LG

 

[tarry99]

"I have also learned that doing things to a Jeep "on the cheap" isn't cheap. You soon will have way more invested than you ever thought you would."

Good Luck!

Bill D

Best line I have heard in years......................I wish more of the folks out there prescribed to this Theory......................Thanks Bill!