Shock valving on heavy rigs.

Hey all. Trying to figure out what to do about my rear suspension bottoming out, and/or deal with on-road ride quality.

98 XJ, 5.3L/4l65e, 6.5" lift, long arm front, 63" chevy leaf rear, blah blah blah.
Rig is about 5000lbs now, and while I've done a tonne of work to the suspension, it's still not quite right.
Front weighs 2470lbs
Rear weighs 2670lbs

I've also got a full size roof rack (only about 80lbs) and a swing out tire carrier with full size spare. The lift, plus tires, plus sprung weight, plus 63" leafs all conspire to make for a bit of a squirmy ride. I ended up adding an XJ main leaf to the bottom of the 63" pack to stiffen things up for now, and it certainly did stiffen things up nicely, but it also gave me a little more lift than I wanted and the ride is much harsher. Ride with just the stock 63" 3.5" lift chevy pack was amazing on the trail, and soaked up absolutely everything really well, but on the highway it'd sway a bit into the danger zone, and on the trail over the moguls, it'd bottom out constantly.

Bottoming out ain't a big deal as I can bumpstop the hell out of it, but I don't like that being the ONLY answer, nor do I like adding a leaf. Both answers aren't really solutions. More like bandaids.

This seems like the correct answer should be in the shocks. Currently running some 12" bilstein 5125's, through the floor, dead vertical. They do ride nice, but I feel like they're not valved stiff enough on either compression or rebound for my weight. I think they're supposed to be 255/70, which for a stock XJ would probably be a bit stiff, but with 2600lbs of ass end flopping around, I feel like I should go stiffer still.

Thoughts/input on this? I don't like adding a leaf to solve what honestly, is a shock absorption problem.

You need to get to a professional level shock and have a professional tune them.

cal said:

You need to get to a professional level shock and have a professional tune them.

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If I took that advice every time it was given, I'd now be the proud owner of $100,000 worth of Jeep worth $7000

I do know a bit about shocks. My downhill bikes shock is 20 years more advanced than any automotive stuff under a few grand/shock. I know how to tune compression/rebound using SCIENCE! but as I don't have adjustable valving, just buying and testing shocks gets hella expensive in a hurry. I'm sure someone else out there is running a similar weight XJ with similar lift, and already has valving their happy with. I"m looking for their input.

I'm sure it's the sprung mass that's killing me, but even if I added more mass to the axles (ie: tonnes), while that solves the problem of tipping over, I'd still be swaying like a retard on the trail. Given all my shocks are vertical, and 255/70 valving, I expect less sway, especially on rebound, but alas, it bobs around all over the trail and I feel like a stiffer shock (maybe somewhere around 325/100) would be about right.

Just wondering what other guys are running under their built rigs, to deal with the sway. I see a lot of big rigs, and most of them aren't running $4000 of shocks. Granted, mine performs better than anything I've seen for what I've paid thus far, and there are very few Jeeps that keep up to me anywhere I wheel, but the suspension sway is embarrassing, and something I've been meaning to address for a while.

blistovmhz said:

I'm sure it's the sprung mass that's killing me, but even if I added more mass to the axles (ie: tonnes), while that solves the problem of tipping over, I'd still be swaying like a retard on the trail. Given all my shocks are vertical, and 255/70 valving, I expect less sway, especially on rebound, but alas, it bobs around all over the trail and I feel like a stiffer shock (maybe somewhere around 325/100) would be about right.

What I'm looking for, is input from guys who've got heavy rigs and don't have horrible sway, to find out what valving they're using

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I am speaking from experience. This xj weighs about 5200 pounds (4890 on the scale with no occupants). We rolled it about 8 times and tried many things. Finally fixed our problems buy paying a pro to tune them. No recorded valving. You add some. Take some out. Nobody writes down the results.

Other people who have tackled the same problem will tell you the same thing.

You may think you can solve it yourself with off the shelf parts. When you finally pull your pants up and pay to do it right, you will look back and see that it was all a waste of time. Like we do.


I can give you the answer from experience. I can't make you like it.

cal said:

I am speaking from experience. This xj weighs about 5200 pounds (4890 on the scale with no occupants). We rolled it about 8 times and tried many things. Finally fixed our problems buy paying a pro to tune them. No recorded valving. You add some. Take some out. Nobody writes down the results.

Other people who have tackled the same problem will tell you the same thing.

You may think you can solve it yourself with off the shelf parts. When you finally pull your pants up and pay to do it right, you will look back and see that it was all a waste of time. Like we do.


I can give you the answer from experience. I can't make you like it.

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I appreciate that, but again, every step of my build I've been told it can't be done without professional help, and every time I've done it just fine. When I did the 5.3 swap, if I asked a Canadian, they'd say it can't be done without involving a shop and expect to spend $20k and take 6-12 months. If I ask an American, the usual answer is to buy all the pre-fab parts and bolt it in for around $7000 and expect to take 2-3 months.
I ended up fabricating everything but the headers and trans-tcase adapter (only because I didn't have the space for the tools I'd need to machine them myself), spent $3500 including the cost of the engine, and it took me 3 weeks (and one week was just waiting for parts).

I get that there's a science to suspension, but science is sorta my thing. According to my math, I should probably be about where I want to be with 325/100. I don't like guessing, spending, testing, guessing again, spending again, and testing again. I don't mind guessing and testing 20x so long as I'm not buying new shocks every time. That said, I do have some fairly light shocks I may add to my current setup, but at a 45 to divide the valving in half and double the articulation. Perhaps this will just work perfectly, and then I'll have my valve numbers confirmed.
Realistically though, from the prices I've seen from suspension shops to do this, I could buy 10 or 15 full sets of shocks before hitting shop price.

Someone out there knows their valving. I'm frankly surprised you'd spend all that money on your heep, and not even ask the shop what they did to make it work.


I see a lot of guys wasting a tonne of time and money rather than doing some very simple math. Hell, when I did the 63" leafs, heaps of guys told me that there was no way I would be able to determine the correct spring rate to get exactly the lift, compression, and droop I wanted, without just buying a set of leafs, sticking them on and testing. That of course is crap. I did the math, bought the correct springs, and my math was within' 0.75mm of reality (I hadn't accounted for the fact that my hangars also had to be stretched forward and back). I'd say the math worked pretty dern well.

Either way, I've got your input. "Let someone else figure it out". Even if I wanted to spend my entire savings on a shop (I don't), there are no competent shops up here. Hell, I can't ****ing buy wheel studs up here because no one knows how to do anything other than OEM application lookups.

I just wanna hear valve numbers from guys who are happy with their compression/rebound on heavy rigs. Bottoming out my drive-shaft is getting old real fast, but I don't want to bandaid it by bumpstopping too early.

It's cute that you think a shop can do tuning.

I said pay a professional. No professional shock tuner will work in a shop. They will meet you on the terrain that you use your rig on and watch you drive it in your trail, and adjust based on what the wheels are doing.

It's not a science, its an art, and it isn't done on a bench or with a calculator.

cal said:

It's cute that you think a shop can do tuning.
It's not a science, its an art, and it isn't done on a bench or with a calculator.

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That's what several people said about the spring rates as well

Spring rates are very much a science. And really basic math.


Most people still get them wrong, and then bitch about sway.


Your doing that newbie thing where you ask a question and since its not the answer you had in mind, its wrong.. So I am done.


Send a pm to 'randomthoughtsrace'. If he bothers to answer you, he was Bilsteins offroad tuner for a long time.


If he doesnt answer and you ask nice, I will call him on your behalf and ask him to visit this thread.

Beyond that, about 4 people on naxja will have an answer here based on experience. If they tell you 'as stiff as you can get' or 360/180 walk away, they aren't one of the four.

cal said:

Spring rates are very much a science. And really basic math.
Your doing that newbie thing where you ask a question and since its not the answer you had in mind, its wrong.. So I am done.

Beyond that, about 4 people on naxja will have an answer here based on experience. If they tell you 'as stiff as you can get' or 360/180 walk away, they aren't one of the four.

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My question is to those who have heavy rigs and have dealt with sway, what valving are you using. That is a very specific question and the answer is a set of numbers, not a recommendation to spend more on my shocks and setup than everything else on my Jeep combined. Again, I appreciate that it's not a simple problem to solve well, but I'm really just looking for numbers that have worked well for others with similar builds.

360/180 . Yes, I've heard lots of guys say to just get the stiffest, longest, largest diameter shock I can find a way to fit. People are idiots .

My compression is definitely too light, even with the extra leaf added, and I want to remove that extra leaf to soften things up a bit, but doing so of course requires that I add more compression resistance. The rebound is actually already pretty close though. 70 is definitely too light even for stock d44 rear with stock springs with 35" shoes. Makes for shitty cornering, and the axle comes down way too fast after compression.
The compression is the big concern. 5125's aren't really meant to deal with more than 400lbs (per side) unless you're planning on using 9 inches of up stroke. My setup has 7 up, 5 down, but I bottom out my drive shaft at about 5.5" up. I'm planning on comp-cutting the rear so I can move the axle back a bit which will give me another 1.5" compression, which may be enough to slow down all that mass on the moguls, but I still feel it's going to be a bit light at 255. I need about 30% more compression overall, or even better would be +10% across the board, with a progressive valving that bumps to around +70% after 5" up.
*sigh* This is all stuff I can do in a few minutes on my bikes. Externally adjustable compression/rebound, dynamic valve ramps, remote nitro with externally adjustable float, push button valve setting change, nitro bottom out protection.

If this wasn't a DD, I'd be running some air shocks. So much simpler/morecomplicatedbutsimpler.

Actually, after reading your message about the AntiRock, I'm starting to think I should solve this problem in two parts, while also solving several problems. Disco's are great for total articulation, but that says nothing about "USEFUL" articulation. From what I understand, the AntiRock is adjustable (which is nice when your rig weighs 5000lbs and your lift may change often), and should provide roughly the same articulation on the trail, while limiting the flex to "only that which is actually useful" and also decreasing the tippiness in off-camber situations. I suppose I'd lose a little bit of anti-sway on road, but I COULD solve that with a rear AntiRock as well. At that point, I'd just have to worry about my compression valving, in which case something around a 300/90 would probably do the trick.

That said, I've zero experience with the AntiRock. Does anyone have any complaints about it, when compared to discos? Anyone running front and rear AntiRock?

one way or another, you need a properly tuned "professional level shock" as Cal put it.

if you continue to ignore his advice, about professional tuning, I would buy the biggest (diameter) shock you can afford with the highest valving you can get off the shelf and start taking shims out until you think its right.

once you decide to get serious, call these guys:
http://www.alltechmotorsports.com/

for comparison, my rig weighs in empty at 4640lbs. I had my shocks tuned by Alltech (fox 2.0) and it works very well. no idea what the actual numbers are. don't care.

Other than what has already been said.. Not all vehicles are created equal. Hence, why xrig vs yrig vary their shock valving. That said, either buy the best adjustable shock set you can and figure that out. OR, Buy higher valved shocks, and do as rockclimber said and adjust them to figure out what you need. This however, costs more money as you would need to have the shocks recharged every time you pull them apart.

Just because someone has a rig that weighs the same as yours and they consider it's ride acceptable doesn't mean that their solution will work for you. Where the weight is located, the type of terrain, and what you want it to ride like are all huge variables.

There's a reason all the top off-road race teams go and test at different locations and have shock setups just for individual races even when the car is staying constant.

You want a one size fits all solution for a problem that isn't one size. You also keep complaining about how much it'll cost you. We're talking about shocks that'll set you back roughly $2-300 per corner and a few hundred bucks for a tuning session with someone who knows what they are doing. If you just start throwing off the shelf junk at your Jeep you'll soon find that you've spent just as much in crap solutions that don't do the job.

You're getting the answer to your question, it's just not the one you want. Sorry nobody is willing to lie to you.

I had my 9100s set up by Joel based on some rough guesses on my rig's weight and setup before he built them and sent them out to me. Never had a chance to get them properly tuned (parted the jeep out two years later) but damn... I've never driven any XJ that handled that well on road and off, slow or fast. It was probably pretty close to cal's original setup before they started tuning. I never raced, so it being perfect wasn't a huge issue like it is for someone racing. I can tell you, the valving is FAR above any of those number bilstein uses for their off the shelf stuff... I asked Joel what the equivalent was and he said it was immeasurably different and much stiffer. I lost the receipt that had my shim stack written on it years ago.



Rig weighed a hair under 5100lbs with a full tank of gas and some camping gear, no driver. Dealers front/rear... 11" travel 2.5 9100s up front, 13" 2.0s 9100s out back. Kind of like the "crazyjim specials" but non-piggyback and no ICV. progressive poly bumps front and rear and I never had the room where I live to move fast enough to get it to bottom out hard.

XJLI said:

I had my 9100s set up by Joel based on some rough guesses on my rig's weight and setup before he built them and sent them out to me. ... It was probably pretty close to cal's original setup before they started tuning.

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Our shocks came with no valving in them at all (as race shocks do), they are intended from day one to require tuning.

It was funny, our first test drive with the car, you would hit a bump and it would just bounce for the next 300 feet.

cal said:

It was funny, our first test drive with the car, you would hit a bump and it would just bounce for the next 300 feet.

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Isn't that how you're supposed to roll the streetz in socal? :dunno:

StinkyFab said:

Just because someone has a rig that weighs the same as yours and they consider it's ride acceptable doesn't mean that their solution will work for you. Where the weight is located, the type of terrain, and what you want it to ride like are all huge variables.

There's a reason all the top off-road race teams go and test at different locations and have shock setups just for individual races even when the car is staying constant.

You want a one size fits all solution for a problem that isn't one size. You also keep complaining about how much it'll cost you. We're talking about shocks that'll set you back roughly $2-300 per corner and a few hundred bucks for a tuning session with someone who knows what they are doing. If you just start throwing off the shelf junk at your Jeep you'll soon find that you've spent just as much in crap solutions that don't do the job.

You're getting the answer to your question, it's just not the one you want. Sorry nobody is willing to lie to you.

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Not complaining about the money. I don't mind spending the money, but I like to know what I'm getting, and why. Either way though, there's no such thing as a suspension tuner for "a couple hundred bucks" up here. I don't even know of a guy this side of the border who does anything other than shop setup, and even they work out to roughly $1000/h, and if they're anything like any other automotive tuners here, they'll do a worse job than I would and by the time they're done, they won't be able to tell me what they did. It really is that bad here. I got quoted (from 3 different shops, 8 years ago) over $1300 to run a single rear brake line for my Eagle. Previous owner of my first Jeep spent nearly $5000 at shops, trying to track down an electrical gremlin that took me about 20 minutes to find and fix (for about $0.03).
I know things are different down in the US. I hear nothing but good things about tonnes of mechanics/tuners/fabricators, but up here, it's just not possible to pay for competent help. This is the number one reason why I've always done everything myself. Hell, I have to argue with the parts counter guy about what part I want to buy, because they insist that a a set of Liberty rear disc brakes cant' be fit onto and XJ D44 axle. They outright refuse to sell the part I want unless I lie and tell them it's for a Liberty of this year/model .

blistovmhz said:

Not complaining about the money. I don't mind spending the money, but I like to know what I'm getting, and why. Either way though, there's no such thing as a suspension tuner for "a couple hundred bucks" up here. I don't even know of a guy this side of the border who does anything other than shop setup, and even they work out to roughly $1000/h, and if they're anything like any other automotive tuners here, they'll do a worse job than I would and by the time they're done, they won't be able to tell me what they did. It really is that bad here. I got quoted (from 3 different shops, 8 years ago) over $1300 to run a single rear brake line for my Eagle. Previous owner of my first Jeep spent nearly $5000 at shops, trying to track down an electrical gremlin that took me about 20 minutes to find and fix (for about $0.03).
I know things are different down in the US. I hear nothing but good things about tonnes of mechanics/tuners/fabricators, but up here, it's just not possible to pay for competent help. This is the number one reason why I've always done everything myself. Hell, I have to argue with the parts counter guy about what part I want to buy, because they insist that a a set of Liberty rear disc brakes cant' be fit onto and XJ D44 axle. They outright refuse to sell the part I want unless I lie and tell them it's for a Liberty of this year/model .

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I sent you Joels username. Send him a PM, ask him for some suggestions on where to start with your setup, then call up Bilstein and buy some shocks and a big stack of shims.

You can do it with Fox, King or Sway-A-Way stuff as well, but it will be more difficult to get free tuning advice on those (Although there may be a SAW hookup around somewhere if you could track him down).

Man, you guys got it made down there (other than the constant Freedom being served out by your police/government).
I do 95% of my shopping in the US because it's that much cheaper, and because parts/stuff simply aren't available down here. Dunno if I mentioned in this thread, but when I did my 5.3 swap, I priced it out in both Canada and the US just for comparison. If I'd bought in Canada, I'd have still had to buy half my parts from the US because no one carries anything up here, but the Canadian price worked out to a bit over $10,000, not including the motor, and I'd have been waiting for 3-6 months for delivery. US price was around $2600, complete, shipped and delivered in under a week.

Fox 2.0's, nitrogen fill kit, shim kit, and patience.

blistovmhz said:

Not complaining about the money. I don't mind spending the money,

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Really? You've brought it up in every post.