Softest 4" lift kit, on road pressures, suggestions?

[ww2steel]

Hello everyone, this is my first post on here!

Okay, before roasting me, I did look through the forums and read everything (I saw) that was related. I have a kind of all encompassing question here pertaining to modified vehicle ride quality.

The brief background is that I owned the Jeep in high school and heavily modified the driveline. It was on BFG 33" ATs with new but stock springs. It gave a normal Jeep ride. I sold it in '97 and refound it in July of this year ('10) and bought it back! My driveline is all still in there just as I did it, but the guy that owned it had modded the suspension. He tried to take really good care of it, but the place that did the mods did a unprofessional job - the lift is a good example. No dropped pitman arm, the brake hoses when sitting still are pulled tight, etc. (I heard hoses from a '80 C30 will work?)

Maybe I am forgetting how the ride felt originally, I'm not 17 anymore after all, but the ride now is VERY harsh. A bump that is barely noticeable in my car crushes your back, twists your neck, slams you against your seatbelt, and will quite literally eject anything in the back seat that you forgot to tie down. With the shocks OFF (removed) and 15psi in the tires it's still rough. As a matter of fact, the springs are so hard you can't even tell the shocks are removed because the springs just don't flex!

To the questions:
1) It's a Superlift 4" kit. I have seen the Skyjacker stuff. I know it is called "Softride" but is it as such, and should I spring for a $760 kit to hope for a better ride. If it's really nice and soft, sure, I'll buy. What is the softest ride on a ~4" lift? What does this sacrifice? It must sacrifice something to go soft or they would all be soft. It seems articulation would be improved by softness. I am aware that my current tires will rub at anywhere near full articulation.

2) I read that the tire pressures on a light vehicle should be aired down even on road for ride quality. I have the bias ply 38x12.5R15 Super Swampers. It said to air them down until you get the slightest sidewall bulge (I imagine the same as you would see on a car) and that should be appropriate as they're also worn by loaded 1 ton pickups. I aired mine down to 15psi and the ride is better, but still very harsh, still no sidewall bulge at all but no new wandering/ steering problems either. They are worn in the center substantially more, either due to tire pressure overage or because the rims are too wide (14" wide rims and the tread is only a 12.5".) Yeah, they look really cool, but I'd rather go shorter and a little wider on the tires.

3) It seems the shocks should be mounted collapsing boot down, not up. I thought you wanted to keep the suspension light for faster movement... not like it matters when each wheel and tire weigh 120lbs, but... Does it matter? Does anyone remember how the shocks were oriented originally?

4) Why on Earth would anyone want the ride that hard? It's seriously going to break things on the vehicle just going down the road at 25mph! I would really like it to ride like my van (Caddy ride), then for offroad I can disconnect the sway links and (with slightly smaller tires and new brake hoses) the soft susp should articulate smoothly. Right now there is practically NO articulation, so the second you diagonally load the suspension (opposing corners are loaded) the unloaded tires just spin. Sure, I can put in a Limited slip, but I want to get the suspension right first!

I'll add some pics soon!

Thanks!
Mike

 

[BrockGrimes]

We don't flame on this board, LOL.

I ran a 4" Super Lift with 33x14.50x15 Super Swamper TSL's
on a '79 CJ5 , it road pretty good. But if you correct what's missing
from your current setup it might ride alot better.

Extended Brake lines:
Brake lines ? - JeepForum.com

 

[BajaEdition]

No Flames, but a lot of no BS advice not given at the larger I have to lift my jeep 30 feet and have articulation to twist 3 times around type forums
Here we love CJs and no matter what you want we will help you with it/

1. I think the 4 inch lift is a lot of the ride problem, any time you go for 4 inches you are going need stiffer springs, do you think maybe 2 and a 1/2 inches might work better for you?

2. Holy where did you get those 14 inch wide rims? for a 12.5 you need a 8 to 10 inch rim, and 8 is just fine. Airing down for the street? no way, when you air down the side wall flexes a LOT, at highway speeds this means they heat up and fail, Airing down is for slow speeds offroad.

3. Shock mounting depends on the shock, some are up and some are down.

4. Hard ride with no articulation is a poor package. You need to work it out a bit and research a way to get the ride and height you want. Remember trends come and go but a classic ride is in style forever.

 

[CJKrawler]

Take a look at Old Man Emu. They worry less about the lift amount, and more about the ride quality. As Baja said, the higher you go, the stiffer the spring. With just 33's, you should be able to get away with 2 1/2" and be ok with minimal rub, depending on your tire of choice.

 

[ww2steel]

Alrighty. Thanks.

Do we have any definitive answer on if the Softride is actually softer?

For clarity ref my first post I removed the shocks just for test purposes to see if maybe they were too stiff. It helped a little, I think the shocks are appropriately valved for a CJ. There was no bounce like a normal vehicle would have if you removed the shocks, again, because the springs have to actually deflect some to bounce!

Airing down the tires comes straight from the manual at Superlift. Standby... here it is directly from the installation manual:

Tire air pressure greatly impacts ride quality. The maximum cold air pressure recommendation of your tires is for that tire at maximum load. Consider that in the vast majority of cases, a Jeep[FONT=Arial,Arial]® [/FONT]will weigh considerably less than a full-size vehicle and has less load capacity. This means that normally you should run less than maximum air pressure for the best possible tire wear, ride quality and handling characteristics. On the other hand, not running enough air pressure will increase tire wear, decrease fuel mileage, increase body roll when cornering, and make steering response sluggish. Your optimum air pressure depends on tire type, tread design, vehicle weight, and driving habits. The goal is a flat tread "foot print" without excessive sidewall bulge. Experiment to determine what air pressure is right for you.
​

This is the first time I remember hearing this, I too only air down for significant off road terrain (meaning almost never). I warmed the tires up this morning and parked it. They have 14-15 psi in them and the weight of the Jeep is not sufficient to cause any discernable sidewall bulge even at that low pressure.

The way I understand it is if there's a contact patch of 12.5x12.5 at 35psi then we have ~156.25in2 and almost 5500lbs of downward force. My car has a contact patch of like 5x5 at 32 psi, it has a small amount of sidewall bulge, that tells me that there is 800 pounds of force resisting sidewall compression. My math certainly is not exact but it works because my car weighs 1650lbs and the tires start to show low pressure at about 15psi, about 400 lbs per tire. Using the same math these giant SS tires with about 750 pounds sitting on each one would need to be aired down to less than 5 psi to start really showing much bulge (750 pounds/ 156 square inches supporting = 5 pounds per square inch required.) Blahhh, I'll go check it out, but that soulds right to me. I would never, ever, drive road speeds with a 5psi tire. Ever. This is just for fun/ my study.

As for the wheels I thought they were Eagles because the center caps says so, but upon closer look the wheels themselves say M/T. When I go to MTs website I found the Classic II wheels, but they only seem to go up to 15x12. When I measure the wheels they are clearly 14" wide at the rim, about 13.4" at the face the tire seats on. They can't be 12 wide. ...but I can't find 14s that look like that. The Eagle 58 series looks similar too, but only up to 12 wide also. I'll keep looking, but until I find a suspension solution in order to keep my vertebrae vertical and these tires from snapping off of my rig due to a .25" bump in the road it's kinda irrelevant.

So, maybe a coil-over suspension is in the works?

Mike

 

[MrFurious]

Best way to improve ride quality in a CJ is to run YJ springs (87-95 Wrangler). Several companies sell kits to facilitate this for a decent price, so then it's a only matter of deciding if you want to run stock height or lift springs.

Here's a link to the kit at 4WD...

CJ Spring Conversion Kit for use with YJ Springs by 4Wheel Drive Hardware® and Other Jeep Parts and Jeep Accessories by 4 Wheel Drive Hardware-RH3

 

[Old Dog]

A couple ?'s
Do you want to keep the 38's? or go with something smaller? Thoes 38's are going to be snapping the stock axles when you go off road.
A bias ply tire has stiffer sidewalls than a radial. Your right I've seen guys air there super swamper tsl down to 5 lb's with hardly any buldge at all.

Is your jeep SOA or SUA? It looks really tall for just a 4" lift.

I have a 4" superlift kit on mine and it doesn't ride all that bad and it flexes ok. Make sure the shackels aren't over tightened and the bushings are greased.

 

[ww2steel]

I saw those YJ conversions and am considering it. I also see some coil conversions that go for about $3000, but at that price there is very little information about them, much less the chance for me to try one out. There's got to be a jeep club nearby, I'll check on that, I'm sure there'd be a lifted Wrangler that I can see how the ride is to know about how my Jeep would ride with the YJ springs.

As for the 38s, not really, I like 'em though. I would want to go with maybe a 36-37" SS Bogger tire so that with the new suspension I can actually use the additional flex without the tires rubbing as quickly.

The full lift package is a Skyjacker 4", 3" body that's been on there for at least 20 years, and about .75" of shackle lift. It's still pretty stable at highway speeds, but I do slow down when I have oncoming traffic.

Yeah, at 5 psi the tires just barely start to flex. I infer that normal steel radials give a better ride even after the bias ply being warmed up?

The AMC20 rear does have solid axles now, but the front is stock later model widetrack Dana 30 . The only axle I have broken in the past was actually climbing a big pile of snow when a tire started spinning under power and suddenly grabbed and stopped and the engine power + driveline inertial snapped the press spline. In that case tire size was somewhat less relevant.

Mike

 

[mylittlecj5]

A couple ?'s
Do you want to keep the 38's? or go with something smaller? Thoes 38's are going to be snapping the stock axles when you go off road.
A bias ply tire has stiffer sidewalls than a radial. Your right I've seen guys air there super swamper tsl down to 5 lb's with hardly any buldge at all.

Is your jeep SOA or SUA? It looks really tall for just a 4" lift.

I have a 4" superlift kit on mine and it doesn't ride all that bad and it flexes ok. Make sure the shackels aren't over tightened and the bushings are greased.

X2. I have the SoftRide 4" suspension on mine, and I think its too soft! But it flexes like crazy for what it is.
Just remember a CJ is not a luxury car...It won't ever ride smooth on or off road.

 

[MrFurious]

Do some research on the YJ conversions. Assuming you're SOA, that gives you roughly 6" of lift in and of itself...more than enough to clear 35's. As such, you really wouldn't need YJ lift springs. However, many have reported sagging with stock YJ springs and often choose to add a long add-a-leaf or go with 1.5" lift springs from OME which helps prevent both sagging and spring-wrap.

Concerning ride quality, your CJ5 is never going to ride like a Caddy so you might as well shelf that dream right now. Between the extremely short wheelbase and the jumbo tires you want to run it's just not going to happen.

 

[ww2steel]

I'll check the shackles. I have ridden in and owned plenty of sports cars and trucks with harsh suspensions. What's on there now is just crazy hard and is going to break things, including me. Ripples you can barely see in the road litterally launch you against your seatbelt at 25 mph. I took a video but need to download a converter to a more normal format before I can share it.

It is NOT spring over. I am more concerned about spring wrap with that V8 than the extra 2+" of lift. I did not pick the tire size, when I sold it it had 33s on it. Now it has these 38s and a series of minor suspension problems I need to fix.

Mike

 

[giantsfan]

when i got my 79 the ride was terrible, bounced stuff out of the back like you were saying. i got a 4 inch rough country lift and did a shackle reversal in the front. made it ride way better. (and the kit came w new shocks) it was only like 550. ill try and find a link to the place, good luck.

 

[RJtucson]

Measuring the rims is tricky. Usually the tire gets in the way of seeing the tape. I think they measure from about the middle of the tire bead. My 10" rims measure just over 12" at the outside of the rim. Your rims are probably 12" if they measure 14".

 

[RJtucson]

As for the tire pressure question, one way to figure it out is to draw a stripe across the tire with chalk. Drive a little, hopefully in a straight line. If all the chalk is worn off evenly, the pressure is about right. If just the center is worn off it's too high, just the edges, too low.

You are right about the large contact patch causing the tire to sag less. My jeep with the fiberglass body and 12.5x33s doesn't sag much. If I see it sagging at all, there is not enough pressure to even move the needle on my pressure gauge. At 10 pounds they look very round.