73 Turnip Wagon Suspension

Guys, I've read a few posts regarding improving ride comfort in my 73... but I haven't seen any magic pills yet. There has to be a some kind of improvements that I can make or trick suggestions to get this thing to ride better. I commute about 20 miles each way every day on a fairly nice interstate but good grief... I feel like I've been riding in a turnip truck all the way. I just put new Superlift shocks on and that helped with the porpoising effect that I was getting when driving over expansion cracks in the highway. It is as stiff as a poker. I can stand on the front bumper and bounce up and down and I only get very mild deflection and I'm 212 pounds. Maybe my springs need greasing or replacing or something. They look fine though... no signs of damage and they don't look like they are sagging or anything like that. I feel like people are laughing at me when they drive by because I'm bouncing so much. I have used the math method for checking ideal tire pressure for max tread wear. Mine came out to about 15lbs per tire, but I'm currently running 20lbs per tire running 50lb max psi BFG 32" tires.

Any ideas that could improve the ride would be great. I'm new to jeeps, but I knew going in that the ride would seem harsh compared to other vehicles. I can take the punishment, but this is soooo stiff it can't be right. It's got about a 2.5 or 3" lift on it, according to the PO.

-Troy

 

Fact of short wheel base . solid axles on both ends = choppy ride . love it or hate it . I heard changing to coil springs helps . but . I have no information on that . it's never going to ride like a truck or car

 

Different companies' lift springs can have very different spring rates. I've been out of the 1 3/4" spring scene for about 20 years, but back then, Skyjacker Softrides were some of the softest springs, while Rancho was the stiffest. I have no idea what is available these days.

As general leaf spring rules,
-Thicker leaves will be more harsh than thinner leaves. A pack of many thin leaves will generally be much softer than the same overall height stack of a few thick leaves.
-Leaves with tapered ends will be more forgiving than non-tapered.
-Springs designed with Teflon sliders between the leaves reduce a lot of friction.

If you are going to go through the trouble of swapping springs for something softer, I'd definitely look into a wider spring, like a Wrangler lift spring with new mounts.

 

NB the spring rate and ride height are the main factors in body roll for these Jeeps. More lift means higher spring rate to be "safe." The original design of a flexible ladder frame with live axles and stiff leaf springs mounted way inboard does not have very good ride quality on the pavement, and it gets worse when you start to lift. The factory "heavy duty springs and shocks" only gave you about an inch more ride height than the standard springs, so a 2.5" or 4" lift is way beyond what the factory would have delivered. Also, to me, 20 psi is high pressure for such a light vehicle and large cross-section tires. I would suggest you run the puddle/chalk test and see what your tread footprint is. I would expect 12-15 psi is more in the ballpark. What is your load rating? Higher load rating means a heavier sidewall for better cut resistance, at the expense of ride quality. Plus a heavier sidewall should need less air for the same footprint.

You don't need a lot of lift to run big tires on a CJ. The main limit is the rear wheel opening diameter which is about 33". The intermediates and lates may snag the leading edge of the bottom of the front fender with that size tire. You can go larger with tube fenders and cutting the rear wheel openings. If you want to go softer you can probably do it without so much lift. Post up some side pictures of you Jeep and detail pictures of the springs and shackles. If you have excess ride height, you can try removing a couple/few of the shorter leaves, thereby losing some ride height and gaining a lower rate.

Jeep began to address the ride vs. roll problem with the 1976 model, by making the springs wider and moving the rear springs outboard. I recall they were also coming under pressure to make the CJ and later Wrangler more road worthy from NHTSA and the Naderites. Additional changes came along later, including a front sway bar, wider tracks, and eventually coil springs, which can move the front springs much further outboard for less roll with no increase in spring rate. The latest Wranglers have gons so far as to use electronic gizmos that monitor traction and (I presume) stability, and intervene as needed.

 

That what i did, went trought 3 set of leaf.

Did the conversion over coil spring, and the ride is not even near the leaf set-up, and i'm not talking about the off-road capacity.

But the biggest issu with a coil spring set-up with a cj5 is the weak frame. You have to box it front to rear, reinforce where the coil bucket goes.

Finaly ended up buiding a hd frame, no issu since that.

 

Dude that looks pretty sweet!

My leaf springs have 9 slats at the center and they are about a quarter inch-ish thick. I really have no way of identifying what they are or who made them. They do have the outer edges cut inward at a 45 degree angle, like the corner edges were snipped.

Tim you are spot on. My math figures for tire pressure suggested 13.5psi in each tire for max tread wear. Jeep is 2750lbs curb weight. It just seemed so wrong to go that low, so I went with 20psi in each.... had them at 40 initially... LOL like a bronco ride. I'll drop it down to 15 and see if it helps. It rides a little better with a full tank of gas.

I'll snap a picture tonight, maybe you guys will know what they are by just looking at them.

-Troy

 

You just need to carry about a half-ton of turnips in the back.

 

If the springs that you are running have no give to them at all, nothing you do will help much short of maybe removing a couple of leaves. On most leaf springs that have some flex, one way to get a much better on road ride is to go with a shackle reversal like the M38A1s came with. Not rocket science, but misunderstood by many people without fabrication skills. There are many factors to a reversal but is much simpler then a coil spring retro. Another simple addition is a winch mounted up front which can easily add 150 pounds by itself and can help cycle the springs. As always start with the basics. Check the pivot and shackle bolts are not too tight to cycle.

 

yes coil spring gave me a good amount of headache....and this mod took me around 400-500 hours to complete on the oem frame. This kind of mod need a lot a preparation and research before starting the project. Just in information research i may have around 70-100 hours behind my computer. You need to fab everything cause there is no aftermarket kit availaible for our jeep.

 

Yep, have seen many rigs destroyed by trying coils, 3 links, 4 links and the like. Good for me as I buy them for pennies on the dollar and then fix them. Very difficult to beat a GOOD set of leaf springs on a short Jeep.

 

Yes, i had my frame destroy in the next 6 month after my conversion, did'nt box the whole frame...but since i put a custom built one, never had issus.


But in my opinion leaf spring are 70-80 era, jeep came with coil spring for a better ride and off-road capacity.
As for my jeep, i won't ever come back to leaf spring when you have taste the coil spring. I have friend who have buggy with coil over and they aren't have the confort i have on the trail.

Just to gave you an idea. i can move wheel up to 35" before another one leave the ground.

 

call Alcan spring and get a custom made pair of springs designed for the weight you carry..

old leaf spring are load carriers, not comfort providers.
with fewer leaves, different spring rates and a tailor product you will see the maximum amount of improvement shy of stretching the WB of the vehicle.

it still wont be as much as you want for as much as you want to pay..

 

FWIW..

I had custom springs made for my Land Rover 109..
night and day difference from the stock 9 and 11 leaf spring packs..
but this is a heavier, longer WB application.. more comparable to a CJ6 hardtop (fully loaded) than a CJ5

 

As a general rule, the flatter the spring, the softer the ride. General rule. Some people have swaped in YJ springs because they are flatter. and older and designed for a bit larger vehicle. SO the old ones are more soft and cushy because they are worn out, but still work for our old CJ's. If you want a little lift, swap to SOA with the YJ springs. You get a lift equal to the spring pack height, the axle tube diameter and the perch height minus any loss of arch going from a CJ to a YJ spring. This is not a straight bolt in, spring width is different so the perches need to be changed. But I believe there are bolt in kits that will allow you to do this.

There is more to this than I indicated but you can do some research to see if this is an avenue you might want to explore.

Then there are custom springs. I had some made by National Springs many years ago and I was, and still am, very happy with them.

 

I have had good luck with the bds springs on mine, just put rough country on the wifes 76 and have been happy with them as well. 16 psi in 235/85/16 on mine. 18 psi in 31/10.50/15 on hers tire pressure plays a huge part in ride quality.

 

Okay, crawled under after getting home to take a closer look at the springs. I did find grease fittings on the front and rear shackles... greased them up real good. Also, I checked the bolts to see if they were really wrenched down tight and they were not, so the springs should be able to articulate well.

I also dropped my tire pressures again to see if that helps. I'm now running 17psi up front and 15psi in the rears. Will test drive again tomorrow.

While I was crawling around under there, I found a little piece of paper stuck to the top side of one of the springs. It would appear that they were manufactured in Dyersburg Tennessee. You guys know a brand from there?

-Troy

 

I think Rough Country is out of Dyersburg, TN.

Yup, they were popular with the tough truck racing crowd because their springs were nearly impossible to bottom out, they were so stiff.

If you don't want to drop the coin on a new set of springs, watch Craigslist. You could get lucky and find a used set for cheap. You can always mix and match different leaves from different sets to get the spring rate you like.

 

If they are rough country, that might be the issue. The old joke in 4 wheeling is rough country described the ride after you put them on.

 

Maybe they are Rough Country then. They are def stiff. I took another test drive this morning following the leaf greasing, steering greasing, and new tire adjustments. I basically greased everything that had a fitting. I actually noticed a good bit of improvement. I didn't get up to highway speed, but I definitely felt a positive change. If it remains as it is at highway speed, I think I'll be happy with it.

-Troy