Pre-runner type suspension stuff

While I realize that something like ride quality is almost completely relative, I really don't think that my jeep rides rough. I prefer a ride that is controlled but not harsh or rough. A little firm is ok, and I think that I would still be happy with the ride if it had a little more damping. When I bought my shocks, I was worried about getting it to stiff also, but I remember when I first switch from DT3000s to the bilsteins how impressed I was with the improved ride. It didn't move around as much and seemed more supple than the DTs. Again though, relative. I would be more than happy to take anyone for a ride who is in the area and is thinking about valving choices. Won't be back in SoCal till summer though. I really don't think it would limit your rock ability any to have valving like mine or even stiffer. When I am just cruising around the desert at a relaxed pace, I disco the front anti sway bar and I fell it is just plush. In fact anything more than a relaxed pace (10mph) makes the front feel way to soft.

When I measure the 7" of up travel, that isn't including the rubber stop. I can't remember how long it is, but I think about 1.5-2". So, measuring as you did, I would have 5-5.5" of up travel, not much different from you. Many jeepspeed guys run the same lift height as I do, but with more bumpstop extension than I do. This is because they run 10-12" shocks that are 2.5" bodys and have a longer compressed length than my short bodies have. They also have 33" tires VS. my 32". That means that many of them sit in the same place in their ride height as you. You should be fine.

I'd like to see some pics of your rear box when you are all finished and have time to snap some. I will have to do the same thing soon.

I've been running the same set of bushings in the axle mount of my rear shocks for about 1.5 years now without any problem. I typically keep them aired up to 200-250 psi and it hasn't been a problem. I've been impressed with the 1/2 heim bilstein puts in standard, they are still tight. I originally got a 9/16 heim on the bottom of the front shocks and that one started clunking pretty fast. It has been swapped for a bushing also.

My dream is to eventually trim the front enough that I can take the 2" bumpstop extensions off and have the front axle stuff as far as it would stock. I would then have to run the shocks through the fender. That would give me at least 14" in the front if the droop is limited in the same place, and I've measured that I can get at least 2" more droop without doing anything extra to the front end... trackbar, steering, etc. Problem is that I don't think any lifted spring is going to have 16" of travel and still be about to compress enough to fit in the stock location when bottomed. So that means coilovers. After that, I just have to figure out what to do with the bumpstop. On the rear, I've thought about running the popular 62" long springs under the axle (with relocated eye mounts also) and shocks into the back for about 19-20" of travel, but I'm not sure if I'm serious enough for all that.

Anyways, I'll be home this summer and I am planning on attending the race Aug. 14 in barstow and most likely prerunning the afternoon before. Barstow is nice and rough and I usually break something... so you should all come :)
 
You mentioned disconnecting the front sway bay.....do you prerun with the sway bar hooked up or not? Do the racers run with the sway bar? I don't mind a stiffer shock, I like the better control in the rocks and the crisper handling. I've run my rear 9000's on 5 both street and trail for a long time, it makes it just a little harsh on the street, but I can take the whoops faster, although 4 is what I prefer overall. I have some dips on streets close to my house that I see how fast I can comfortably take them, as a comparison (I do this with various vehicles from work, too, trying to better understand what works).

I just remeasured my front bumpstops to be sure I remembered what I did. The top is 1/2" lower than stock with the Daystar poly, and the lower is 3.5" with a steel spacer and two hockey pucs. I haven't run it yet with this combo, so I'll see what it does. I am concerned that I have the bumpstops and shock uptravel too close, about an inch difference....I'll watch that and see what it does. When articulating it's perfect, the bumpstop doesn't compress with over an inch of shock travel left.....plenty for bouncing down on something.

I'm charging the battery on my camera and I'll snap some pics and post them of the shackle box repair.

On my lower shock bushings in front, the bushing bound when fully drooped, so I made the mounts a little wider and used the misalignment spacers from Spidertrax on each side of the bushing to give it more room to move.....looks like it worked out well. any idea how much pressure the race guys run in their shocks? Can you tell much difference when you put more pressure in yours? I think I mentioned mine came with 150 psi in the front and 100 in the back, which I'm going to increase before deciding if I want to revalve.

How often are you totally aired out when prerunning?

What tire pressure do you run?
 
Richard, the problem that I found when I had the SAW's valved stiff, or at least when they were valved to work really well at pre-running speeds, was that they didn't react fast enough on the trail. They worked fine if I was going slow enough, but with a softer valving I can go much faster on the trail. Mind you I'm talking 1st gear, low range either way.
Paul
 
Paul S said:
Richard, the problem that I found when I had the SAW's valved stiff, or at least when they were valved to work really well at pre-running speeds, was that they didn't react fast enough on the trail. They worked fine if I was going slow enough, but with a softer valving I can go much faster on the trail. Mind you I'm talking 1st gear, low range either way.
Paul
Click to expand...

I was wondering about that.....how stiff would become too stiff for trail work. There is a test of various remote resevoir shocks in the current issue of Peterson's. It's interesting that the stiffest feeling shock on the street is the Bilstein 5150 with 255/70 valving, not what you'd think was stiff enough for prerunning, but they are charged to 360 psi. The article said they were very compliant on the trail and good for pre-running. The ProComp Pre-Runners are actually good SAW's and they were not quite as stiff as the 5150's on the street, very good at prerunning, but not compliant enough for the trail.

Makes me wonder about how much shock tuning can be done with pressure as well as valving. From the difference in performance of the 5150's and ProComps, it would appear that we could run a softer valving for good trail performance but a higher pressure for prerunning. I'll be testing this out with the SAW's, since our's are starting with fairly low pressure. I should have the rear shocks on to do some clerance testing in the morning.

mad maxj, check out that article, one of the four shocks in the comparison are the new remote resevoir 9000's.
 
Goatman said:
I was wondering about that.....how stiff would become too stiff for trail work. There is a test of various remote resevoir shocks in the current issue of Peterson's. It's interesting that the stiffest feeling shock on the street is the Bilstein 5150 with 255/70 valving, not what you'd think was stiff enough for prerunning, but they are charged to 360 psi. The article said they were very compliant on the trail and good for pre-running. The ProComp Pre-Runners are actually good SAW's and they were not quite as stiff as the 5150's on the street, very good at prerunning, but not compliant enough for the trail.

Makes me wonder about how much shock tuning can be done with pressure as well as valving. From the difference in performance of the 5150's and ProComps, it would appear that we could run a softer valving for good trail performance but a higher pressure for prerunning. I'll be testing this out with the SAW's, since our's are starting with fairly low pressure. I should have the rear shocks on to do some clerance testing in the morning.

mad maxj, check out that article, one of the four shocks in the comparison are the new remote resevoir 9000's.
Click to expand...
yeah, i've read that article, and just read it again a few minutes ago. most (all?) of the other shocks are monotube, but the RS9000s are low-pressure triple tubed shocks. does that make a big difference?

most importantly, how much are they going for? i haven't seen any for sale yet?

if they're as much or more than 7100 non-reseviors, than i wouldn't even consider them because I'd rather have perfect valving than a resevoir since my desert jaunts would only be a couple miles.
 
To shed a little light on gas pressure in a rebuildable, revalvable, reservoir shock.
You are not going to make the shock significantly stiffer or softer with a pressure change.
The pressure is exerted only on the cross section of the shock shaft.
Do the math, a 100psi increase on a 14mm shaft shock, an area less than a quarter square inch, is about 24psi.
Not really going to make the shock stiffer.
What is extremely important about the gas pressure is how it works on the oil.
The force the gas puts on the oil must exceed the damping force or the oil will cavitate going through the valving, the shock will fade, and your rig will turn into a flying pogo stick.
A stiffer valved shock requires higher gas pressure than a softer valved one to combat this.
Using unnecessarly high gas pressure will increase seal wear and shock stiction, so a manufacture recommends the pressure accordingly.
This is why Richard's rock crawling shocks use a lower pressure than Marcus's pre-runner shocks.
Raising the pressure in a softly valved shock will not make it stiffer and is unnecassary untill it is re-valved stiffer.
 
What Robert just said.
I carry a nitrogen bottle with me for easy adjustment.....
I have found that my Bilstiens like lower pressure...add too much and they just get harsh and not so compliant.
I run 7100 series and have yet to get them too hot to the touch (they have huge res. on them)
Now for the disclaimer....I don't run these on my cherokee.
I run them on my buggie....
If I ran my cherokee like i run the buggie....it would be a wad of scrap metal by now....are you sure you want to beat the snot out of your XJ....at speed?
Unibodies......I love my cherokee....but these hi speed jobs don't last long!!
Rick
 
Rich,

As you know, I'm in the midst of picking shock valving right now myself. I'm leaning towards 275/78 in the front in a 7100 series, with the new RE 7.5" XJ coil. I think it should be about right. I think when setting up a shock for our dual use applications, we need to keep the much higher front wieght of our rigs in mind. We're carrying a good 100 -125 pounds more out over our front bumpers than the JeepSpeed guys. This kind of extra weight demands more compression damping. The second issue is rebound damping. I think rockcrawlers need more rebound damping to keep the rig from feeling overly tippy when a tire falls into a hole, etc. Third issue, we are generally running a lot more spring rate in the rear than a JS rig, usually because we are hauling a mess of camping stuff!

In summary, I think we need to shoot for both more compression and more rebound than a JS rig.

CRASH

P.S. When you see the new URF "Super Long Arm" in action, you'll be too intimidated to even want to race back to camp!
 
I've tried running without the sway bars before, but it never liked it. I will disconnect them when I'm just taking it easy and cruising around the pits and stiff. I don't like how it rolls the car side to side when going straight, but it more than makes up for it when sliding around a corner or avoiding rocks. If I had twice the damping on all corners I would probably run without the bar. It's way to tippy when disconnected. None of the current racers I can think of run a bar. Ryan Wallace from rubicon express used to race a black 2-dr, and ran a front anti-rock bar, but he's the only one I know of.

To check your shocks, zip tie them and then catch some air (in a safe location of course). Your shocks will flatten the zip tie.

On my lower shock bushings in front, the bushing bound when fully drooped
Click to expand...
What to you mean? Does your lower shock bolt go side to side or front to back? How much does your pinion rotate?

I agree with everyone else about the pressure. I don't think it will change as much as you'd like, or as much as your rs9000s. Racers run around 200 usually, but differences vary as much as 50 psi. Clive Skilton, the founder of jeepspeed has a cherokee set up like mine (same front springs, shocks, and valving). He doesn't like to go much over 150psi because he says it's stiff. I like running around 250psi. Doesn't hurt to play with the pressure though, I encourage you to do it.

Tire pressure is about 28 psi... street pressure. Racers I've talked to run something in the mid-20s.

Honestly, I know that I air out more than I realize. I know that because I was filmed once and was coming off the ground when I had no idea even one tire was up. I probably get high enough where I and my passengers know it 10 times on a prerun. I like air and catch it as much as I can.
 
CRASH said:
Rich,

As you know, I'm in the midst of picking shock valving right now myself. I'm leaning towards 275/78 in the front in a 7100 series, with the new RE 7.5" XJ coil. I think it should be about right. I think when setting up a shock for our dual use applications, we need to keep the much higher front wieght of our rigs in mind. We're carrying a good 100 -125 pounds more out over our front bumpers than the JeepSpeed guys. This kind of extra weight demands more compression damping. The second issue is rebound damping. I think rockcrawlers need more rebound damping to keep the rig from feeling overly tippy when a tire falls into a hole, etc. Third issue, we are generally running a lot more spring rate in the rear than a JS rig, usually because we are hauling a mess of camping stuff!

In summary, I think we need to shoot for both more compression and more rebound than a JS rig.

CRASH

P.S. When you see the new URF "Super Long Arm" in action, you'll be too intimidated to even want to race back to camp!
Click to expand...

Seeing as how I already have a well working three link, and you abandoned your radius arms to go to a 3 link......why would I be inimidated? :dunno: I think it will come down to which of us gets finally gets the stroker motor in first. :D

Good points about beeing heavier and carrying more weight, but from what I've seen and heard the stiffer valving the Jeepspeeders need is still too stiff for rockcrawling. Two examples are the current mag article on shocks where they said the ProComps where the best for pre-running, but the worst for rock crawling....not compliant enough on the trail. Paul said the same thing about testing a stiffer valving on SAW's. I'm sure a year from now we'll have much better info on this as we run them ourselves.

Marcus, my lower shock bolt runs for and aft, perpendicular to the axle housing. Yes, I have just a touch more pinion movement than I want. I'm making a slight modification to the axle end UCA mount, raising the arm a little which should cure it. My CV joint also bottoms out if I let the front end drop all the way to the ends of the shocks. It makes no difference when articulating, or when in 2wd with the hubs unlocked, but in 4wd the limiting strap is needed....to hold it about an inch above what the shocks will allow. Upper arm adjustment will take care of it.
 
Last edited:
RobertF said:
To shed a little light on gas pressure in a rebuildable, revalvable, reservoir shock.
You are not going to make the shock significantly stiffer or softer with a pressure change.
The pressure is exerted only on the cross section of the shock shaft.
Do the math, a 100psi increase on a 14mm shaft shock, an area less than a quarter square inch, is about 24psi.
Not really going to make the shock stiffer.
What is extremely important about the gas pressure is how it works on the oil.
Raising the pressure in a softly valved shock will not make it stiffer and is unnecassary untill it is re-valved stiffer.
Click to expand...

Jump This said:
What Robert just said.
I carry a nitrogen bottle with me for easy adjustment.....
I have found that my Bilstiens like lower pressure...add too much and they just get harsh and not so compliant.
I run 7100 series and have yet to get them too hot to the touch (they have huge res. on them)
Now for the disclaimer....I don't run these on my cherokee.
I run them on my buggie....
If I ran my cherokee like i run the buggie....it would be a wad of scrap metal by now....are you sure you want to beat the snot out of your XJ....at speed?
Unibodies......I love my cherokee....but these hi speed jobs don't last long!!
Rick
Click to expand...


Robert and Rick, you guys are condradicting each other. I know I can't completely understand how pressure effects the shocks until I get mine out and play with it, but there seems to be differing views. Robert says the pressure won't affect it much, Rick says (and Marcus quoted Clive Skilton as saying) that too much pressure makes the shock too stiff.

Based on what I see about shocks, I don't agree that the gas pressure only exerts force on the cross section of the shaft, but I don't yet understand this thoroughly. The gas pushes against the oil, actually against the dividing piston between the gas and the oil so they don't mix. How I see it is that the oil above the shock piston is presurized and the oil below the piston is not....sort of (which explains, to me anyway, why a gas pressure shock always pushes the shaft out). In any initial compression force on the shock, as the piston pushes up through the oil the oil is going to push against and try to compress the gas. So, the gas does two things, it pressurizes the oil to fight cavitation and it reduces harshness by providing some give in the gas as well as resistance from the fluid. I know the fluid can't push up much against the gas, since the fluid can't expand below the piston without cavitation, but harshness comes from that intitial shock, and it seems to me that even a little give of the fluid against the dividing piston/gas will reduce harshness.....if the pressure isn't too high. Those Bilstein 5150's with 360 psi as opposed to the normal roughly 200 psi raises some questions.

Maybe it's time to get a nitrogen bottle and a 300 psi gauge. :)
 
Seeing as how I already have a well working three link, and you abandoned your radius arms to go to a 3 link......why would I be inimidated? I think it will come down to which of us gets finally gets the stroker motor in first.
Click to expand...

Pistons and rods should arive by the end of the week, block is already at the machine shop getting prepped. :D

Now the debate will rage over long three link (all my arms are 38" :D) ) vs. short 3 link!

Now you've got me wondering if the 275/78 rate is gonna be too stiff for the rocks next off-the-shelf rate down is 255/70. How do either of those rates compare to the SAW's? I think you said that you can convert SAW ratings to newton/meters, like the way Bilsteins are rated?

CRASH
 
can someone post a schematic of these shocks? if the entire inner chamber is under the pressure of the gass(the piston has holes in it, so its not like an engine piston) it would seem that the cross-sectional area of the shaft is what the pressure is acting on.



did someone say that there is a rs9000 with res?
 
Remember back a few post ago when it was suggested that you change the motor mounts? YOU MUST DO THIS IF YOU ARE GOING TO GO FAST! In one of my Cherokee's we went jumping and we busted the mount out of the block on the passenger side. I eventually fixed it, but this should be your highest priority. Get the good mounts in the motor/trans. And change the bolts in the block to the motor mount to grade 8. You don't want to go to all the trouble of creating a trick rig only to be sidelined with a busted block....learn from our mistakes :twak: :anon:
"first things first, the rest will come easy"
highmobilityinc.com
 
jjvande said:
can someone post a schematic of these shocks? if the entire inner chamber is under the pressure of the gass(the piston has holes in it, so its not like an engine piston) it would seem that the cross-sectional area of the shaft is what the pressure is acting on.



did someone say that there is a rs9000 with res?
Click to expand...
yep, Rancho RS 9000X Pro Series. they're in the June Petersons in their resevoir shock comparison article
 
mad maXJ said:
yep, Rancho RS 9000X Pro Series. they're in the June Petersons in their resevoir shock comparison article
Click to expand...

They are retailing for $179, about $5 more than a remote reservoir 12" travel 7100 Bilstein.

What a deal.

Not.

CRASH
 
CRASH said:
They are retailing for $179, about $5 more than a remote reservoir 12" travel 7100 Bilstein.

What a deal.

Not.

CRASH
Click to expand...
thanks for that CRASH, that's all I need to know.

i'd rather have 7100s without resevoirs than 9000s with resevoirs.

maybe one of these JeepSpeed guys can answer this: How many miles, or how much time, of typical desert running does it take to overheat good (7100, etc) non-resevoir shocks? This of course has a ton of variables, but can you give me a general idea? 1? 5? 10?
 
crash, the 275/78 in the front felt good on the trail the two times I have run it.
But it was out at JV. Going very slow.
This summer on the con going along at a second gear pace is where it might be to stiff.
I'm just planning on getting hyd bumpstops to finish of the front. It's the only good way I see to get a progressive front end.
 
You must log in or register to reply here.

Similar threads

macgyvr
Prizes for NAXJA members who pre-registered for Winterfest!
Replies
3
Views
130
REWSTER
REWSTER
C
Seeking Tuning Advice for Gen 1 SVT Raptor Shocks on a Jeep XJ
Replies
1
Views
173
Evan03
E
EricsXJ
2025 Reno Fest - Memorial Weekend - High Rock Canyon (preparation thread)
Replies
14
Views
343
EricsXJ
EricsXJ
1
Feeler for sale of my XJ crawler.
Replies
0
Views
461
1-tonxj
1
N
  • Locked
Lowering An XJ
Replies
0
Views
364
NAXJA_Archives
N
Back
Top