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I recently purchased new shocks for my Trooper. I ended up buying fox reservoirs front and rear. I bought the 6 inch for the front and the 8.5 for the rear. The fronts came with a single 14 inch 250lb spring and bolted right in. The rears are setup with a 425 over 500 and needed a limit strap to limit the last bit of stroke. When I took it out for a ride it felt better than stock but still felt somewhat harsh on the sharper bumps (pot holes, rocks, etc.)

My question is- Is the compression not right or the springs. I am pretty sure the 425 in the back is too light and I am probably gonna go to a 475. After preloading about an inch I still only have 9 inches of ground clearance. The rear feels softer, but not soft enough. The front strokes better but is still way too harsh.

I am valved at 65/80 in the front and 70/90 in the rear. It seems like too much, but I am not sure. What do you guys think?

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Note how soft my damping is!!!

Posting from last year.

"Final setup,

Rear is double shocked using the stock Joyner shocks as the spring setup with very little or no dampening. I bled ALL of the N2 pressure off of the shocks. The Fox shocks' dampening is adjusted to 35 / 55 (compression/extension). Front tire pressure is 13 1/2 lbs. The load on the springs was backed off 1 3/4" to 2" softening the load on the springs & lowering the ride height."

Here is the complete posting with a lot more info from Lenny as well, http://www.utvboard....ea/page__st__20

rocmoc n AZ/Mexico

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Add more preload in the rear. For every 1/2" of preload you will gain about an inch of ground clearance. You should be fine going up to 2.5-3" of preload. I believe your valving is too firm. Remember though, the softer you go, the more sway/slinky you will get in turns. What psi are you running in your tires?

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When I talked to the guys at Fox, they told me that you can only preload to coil bind. This is where the air space between coils is less than the amount of stroke left. I think I am close to this point now, I am pretty sure I should use a little heavier spring. I run from anywhere from 8 -15 psi depending on what I am doing. From what I can tell I should probably change the valving to a 40/60 in the rear, but what about up front?

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Preload can stiffen the springs. I added ground cleanance via Larger Tires and took preload off the springs to soften the springs & ride. What is also inportant is the angle of the axles coming off the diffs. Mine are nearly neutral so I have max travel in both compress & extend of shock travel. Joyner, IMHO, put too much preload for ground clearance at the expense of proper shock action & CV joint health. Springs should be soft enough to cause a fair amount of sway when you dirve. You should be able to grab the rollbar from the side and lean the T2 fairly easy with your weight & pulling side to side. The sway/soft shock action keeps the wheels on the ground when going thu rough stuff and rock climbing. I still need to soften more. When I drove Lenny's T2 I noticed his is really soft much more than mine. This is where I will adj to. If the springs are too hard you will be more of a flat tracker, sliding instead of biteing into the surface. Notice how Nascar race cars have nearly NO shock action, smooth surface, and off -road racers have a ton of shock action, rough surface. You will like the 40/60 much better but you need soft springs to take advantage of the damping. Just a WAG, Wild A*s Guess, but I would go at least 40/60 in the front also. Remember you are lighter in the front requiring less spring rate. The Fox guys should know some of this stuff, my guy did when I bounce my choices off of him. Good luck.

rocmoc n AZ/Mexico

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When I talked to the guys at Fox, they told me that you can only preload to coil bind. This is where the air space between coils is less than the amount of stroke left. I think I am close to this point now, I am pretty sure I should use a little heavier spring. I run from anywhere from 8 -15 psi depending on what I am doing. From what I can tell I should probably change the valving to a 40/60 in the rear, but what about up front?

Yes, coil bind is a concern, but I believe you should be able to preload more. I know you are a smart dude so if you haven't measured yet (I ask this because you said "I think"), measure the space between the coils and compare it to you shaft length remaining. I though I was close too, but when I reviewed some slow motion video I could see I had a lot of space between the coils even when I bottomed out.

How much droop do you currently have front & rear? Jack it up so the tires are just barely touching & take measurements from the bottom of the skidplates to the ground. Also, take a measurment of the amount of shock shaft showing if you don't already know this number. Then downjack it, start it up and move it back and forth until you are comfortable it has settled in, then remeasure. Your travel in the back has increased with the new shocks, so I would recommend at least 1" of droop on the shock itself which will probably equal about 3-4 inches of droop in the rear. Allowing at least 1" of compression in the shock helps it to operate in its optimally designed range.

Once I hear back from you on the front droop I will address that. Remember, I am running dual rate in front, so I will help you out the best I can. Also, I have not played with my valving yet, so I have no idea what I am set at because I bought these shocks used. They came off of a 800lb mini-rail, so they are definately on the soft side for a 1800lb trooper. But I have no complaints on rocky trails & Moab which is what I do most. If I did alot of duning and big whoops I would need to firm up my compression & rebound.

I believe you are still running 27" tires. Is that correct? Are they the stock tires? I am running about 5-7 psi in my 30" tires. What tire & psi will make a big difference in your suspension too. Unless you have the exact same tires as me we are, to some degree, comparing apples to oranges.

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  • 2 months later...

I am ready to change the springs on my shocks. I have them preloaded at least 3 inches and still not enough ground clearance. How much bigger should I go? I am at 425 with about full preload and just sitting there I get into my main spring (500) a little bit and only sit about 8.5-9 inches off the ground. Should I go to a 500 over 550? Is that too much? I just have to get the back end up about 3-4 inches.

The front still seems to ride too stiff. Should I got to a lighter spring (currently at 250)? With 0 preload I am at 14-15 inches of clearance. I was thinking I should go to a 200 or 175 and preload a bit to get 13-14 inches of clearance.

What are your thoughts?

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Guest Lenny

Try bringing your compression down to about 20 and your rebound up to about 80-85. This will allow softer compression and help stop bounce off of compression which makes the ride harsher. You could try heavier springs too. Also you should have 1-1/2" to 2" inches of shock travel before getting into the primary spring. This will help you stay soft on the smaller stuff. Then if it were me, I would consider upsing the primary spring on the front. You can also consider using a longer tender spring if you have room but that only works if your showing enough threads above the adjustment collar to accept more length. You can determine the amount of load that is on the spring by measuring its length when your just setting there. If it's a 425# spring, it is going to be loaded the unloaded spring length less the preloaded length times 425#. With that you can determine the preloaded length of a softer tender spring to see if it will fit. Same with the primary spring. You have to sort of juggle between primary spring rate and length and tender spring rate and length. Here is what I am doing which is different from your setup but will give you an idea of just how far from common thought you can get. My fornt shock uses a 200 x 10" tender over a 200 x 16" main on a 10 fox shock with compression at 20 and rebound at 80. It is still a bit stiff so im planing on trying a 175# x 12" tender. I can then still crank it down to get ride height without forcing it to get into the primary spring too soon. Thats going to be 28" of spring on a 10" travel shock. To do this you have to use high quality springs like Swift springs which use a superior material allowing smaller material diameter size which helps keep you from spring binding with this much spring on the shock. My rear, also a 10" tarvel shock and uses a 325# x 10" tender over a 450# x 14" primary with compression set at about 25 and rebound set at 90. My rear shocks are almost perfect.

Here is a link to the geometry I'm using on the rear.

http://good-times.we...104928832lnWwUP

Hewre is a link to some pics of what I have done. You will see I made the top shock mount adjustable. Makes expirmenting much easier. http://entertainment...582253127ksMIxo

Lenny

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Now I am more confused than before :D My front shocks are single rate. Rears are dual. Will changing compression change ride height? I was under the impression that spring rate and preload determined ride height. Basically my problem is a stiff ride in the front and a good ride in the rear but not enough ground clearance. Does this change anything you said Lenny? Please excuse my ignorance.

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Guest Lenny

Now I am more confused than before :D My front shocks are single rate. Rears are dual. Will changing compression change ride height? I was under the impression that spring rate and preload determined ride height. Basically my problem is a stiff ride in the front and a good ride in the rear but not enough ground clearance. Does this change anything you said Lenny? Please excuse my ignorance.

Changing compression won't change ride heigth but it will change stiffness. Only pushing down harder with the springs will change ride heigth. While, loosing vehicle weight will too. If you want to raise the ride heigth on the front, you either have to go to heavier springs or preload more. Either one will further stiffin the ride. However you could consider a longer spring in front and not increasing its rate or even go less, if you don't get bind. For example if you have a 12" 200# spring now and you preload say 2" of that and you have 4" of shock shaft showing yet after preloading, you then have 4'" further you can compress the spring. That means that you need to be able to compress the spring the 2" plus the 4" without spring bind. Thus the spring should be able to compress 6" without bind. A cheap spring or older used spring may be bound when compressed only 5-1/2" meaning you would have 6-1/2" of spring when bound thus the above would not work. A top quality spring may go all the way down to 4-1/2"before binding when fully collapsed thus giving you 7-1/2" in which you can compress the spring. In the above example, going to a high quality spring, you could then preload another 1-1/2" or push down an extra 300 pounds without increasing the spring rate. You will be stiffer at the start of suspension travel but your rate from there down would be still 200# per inch of compression. If you put a heavier spring in to push down an extrra 300 pounds, you would start out the same stiffness as above where you added another 1-1/2" of preload. but the differance is that from that point on you would be stiffer then above because now your spring rate would be more then 200# per inch. Now if the 12" long spring binds to soon and you can get say a 14" spring in, then you possibly could pick up the extra spring travel without binding and be able to hold your present rate. This is where this same concept works on going to a lighter spring. It's compicated and that is why many people don't understand it.There are a number of things you can possibly do to soften the ride while increasing your ride height. They all may increase the ride height and start from there at the same softness but they may have very different results in ride from there down. I always start by juggling springs on paper, trying different combinations. If you get the ride real soft but are bottoming out, then yuou can increase the compression dampening to stiffen it up as necessary. Remember valving has a greater effect as the speed of compression increases. Going slow over say a 12" hump may be fairly soft but the higher compression dampening will keep it from bottoming if hit at speed. Your slow increass in stiffness will be much less. You can get a lot more complex when you start considering shock angle and placement and when you go to dual springs. You could right a book on it so it's impossible to learn it quickly but if you understand the basic concepts, you can get pretty good results.

Lenny

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Ok I think I get it a little better. My front end is almost too high (if that's possible). It sits around 15 inches. The rear end sits at about nine inches. So I am trying to soften the front end and raise the back end. The back end feels good but sits too low. That is why I was thinking of going to a stiffer tender spring and possible stiffer main. I am mostly looking to raise the rear end up. I can live with the front as is but would like to see it a bit softer. I am running a 14 inch 250 in the front and was thinking of going to a 200 as that is what most others have.

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Guest Lenny

Ok I think I get it a little better. My front end is almost too high (if that's possible). It sits around 15 inches. The rear end sits at about nine inches. So I am trying to soften the front end and raise the back end. The back end feels good but sits too low. That is why I was thinking of going to a stiffer tender spring and possible stiffer main. I am mostly looking to raise the rear end up. I can live with the front as is but would like to see it a bit softer. I am running a 14 inch 250 in the front and was thinking of going to a 200 as that is what most others have.

I keep my front at about 15" off the ground. The 200 pound spring might be fine. I would see if you can go with a 16". If you want to run at 15" or be able to go there for rock crawling for example, a 14" 200 pound spring might reequire too much preload to give you that heigth and not have enough left before binding. A 16" might help this situation. If you measure the heigth of your current 250# spring as it sets under preload, you will know how much it is compressed and that times 250 will be how much force the spring needs to push with in order to hold you at your current heigth,. If you take that force and divide it by 200, you will know how much a 200# spring would need to compress to acheive that same height. If you have enough room above the adjustment collar based on where it would be with a 200# x 12" spring, you should be able to determine if there is enough threads left above the collar to move that collar up 2".

Lenny

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ok, that should take care of the front. What about bringing the back end higher. Given that i am at or past full preload with the current 425 tender over 500 main and still about 3-5 inches low, what are your thoughts on spring rates to bring it back up to 13-15 inches of ground clearance. Thank you for the information given thus far.

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Guest Lenny

ok, that should take care of the front. What about bringing the back end higher. Given that i am at or past full preload with the current 425 tender over 500 main and still about 3-5 inches low, what are your thoughts on spring rates to bring it back up to 13-15 inches of ground clearance. Thank you for the information given thus far.

What are your spring lengths and what it their length as preloaded? If I remember, your using an 8" shock. When your preloaded, how much shock rod is still showing? Thus how much dies it have to yet collapse? If you jack it up to say 14" clearance, what are the spring lengths then and how much shock shaft is showing?

Lenny

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Ok as it sits there is a total spring length of 13 7/8 with the divider. 5.5 is tender 8 inch is main. With 5.5 of shaft showing. At 13 inches of clearance ( as I am running 27s still). Total length of 15.25 6.5 tender 8.75 main 7 5/8 of shaft. This will limit my up travel as this puts my axels about 1 inch from the trailing arm. I am ok with that. There is also about 2.5 inches of thread from top of spring ( not nut) to top of thread. Thanks

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Guest Lenny

Ok as it sits there is a total spring length of 13 7/8 with the divider. 5.5 is tender 8 inch is main. With 5.5 of shaft showing. At 13 inches of clearance ( as I am running 27s still). Total length of 15.25 6.5 tender 8.75 main 7 5/8 of shaft. This will limit my up travel as this puts my axels about 1 inch from the trailing arm. I am ok with that. There is also about 2.5 inches of thread from top of spring ( not nut) to top of thread. Thanks

I guess I'm going to need some more inforrmation. What are your spring lengths un-compressed like they were setting out on the table? When your setting with your preload, how far is the top of the divider collar from the stop ring. I need you to measure the all the spaces inbetween each coil of both the tender spring and the main spring. This when added up will provide 2 totals, One for each spring. This will give us an idea off what the height of each coil is when fully compressed. If you know what springs you have you may be able to look up the compressed height. I need this for both tender and main. Looks like you can go to a 2" longer spring ok at this point. Still need to decide which spring wants to be 2" longer. Also if you might need a stronger spring which would probably be the main spring if you do. I went thru about 15 sets of springs when doing mine. This includes a lot of learning. If I did it now, I could do it with far less. I bought them fairly cheap on Ebay then resold them and about broke even. Didn't care if I didn't get top quality. Once zeroed in, I could then get better springs which are somewhat more expensive. I also have changed my dampening 15-20 times. The shims are cheap and changing them yourself if quite easy after the first couple of times. If your going to get it to do what you want, your going to have to get a feel of ust what is happening with the suspension when you ride in different terrain. Watch motorcross and or baja throphy trucks on YouTube and study just what it is acting like when they hit a bump and just after hitting the bump. You shouldn't bounce like a pogo stick.

Lenny

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Now I am more confused than before :D My front shocks are single rate. Rears are dual. Will changing compression change ride height? I was under the impression that spring rate and preload determined ride height. Basically my problem is a stiff ride in the front and a good ride in the rear but not enough ground clearance. Does this change anything you said Lenny? Please excuse my ignorance.

What is the stock clearance on a Trooper with 27" tires? I would guess it is around 11-12 inches. So, obviously you are too low in back and too high in front. I would simply gets ligher springs in front and heavier in the rear. I would try a 150lb in front and 500 over 500 in the rear. If that is still not enough in the rear, go to a 550 or 600 lb primary. One other option is to move your rear shock mount back. This will reduce the leverage on it and support the rear end more; however, you will lose some travel (like an inch or two).

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Does any one think that air shocks that can be pumped up for higher clearances when needed and have little or no effect when not pumped up would work or is it a dumb idea? I'm thinking I can have a nice soft suspension for roads and then pump it up for the rough stuff.

kinarfi

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Guest Lenny

Does any one think that air shocks that can be pumped up for higher clearances when needed and have little or no effect when not pumped up would work or is it a dumb idea? I'm thinking I can have a nice soft suspension for roads and then pump it up for the rough stuff.

kinarfi

It might work but the charactistics will be different. I'm going to think out loud here for a minute. A 10" long 200 pound spring when compressed 1" at a ime and the resultant pushing force compaired to a 10" stroke cylinder with 200 pounds of push after compressed 1", like the spring would be at 1" and a 7" stroke air cylinder at 200 Pounds at 1".

compression spring 10" air 7" air

0" 0# 180# 171#

1" 200# 200# 200#

2" 400# 225# 240#

3" 600# 257# 300#

4" 800# 360# 400#

5" 1000# 450# 600#

6" 1200# 600# 1200#

6-1/2" 1300# 720# 2400#

6-3/4" 1350# 800# 4800#

6-7/8" 1375# 847# 9600#

As you can see, the 7" air cylinder would be much softer then the shock up to 5" of stroke then rapidly get stiffer. There may be a combination that would maybe work and it would be interesting to play with the idea. Without playing with it further, I'm thinking an 8" spring starting out at maybe 300# at 1" would be getting close. One thing about air is that you can quickly change the starting pressures. You would have to be careful not to get into the higher air pressure numbers as the air cylinder will be limited on just how much it can take. It would provide a plush ride and still may be able to catch the harder hits but it would catch them much harder. Real soft thru the first maybe 2/3 down then getr real stiff quickly. Rock crawlers use long air shocks so they are real soft through their used travel. They want their wheels to move up and over stuff easily without tipping the vehicle hard or lifting other wheels off the ground.. I think this is all pretty close thinking but I have never really looked at it for suspension before. Maybe someone else has some input a lot smarter then mine.

Lenny

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I just read on the King shock web site that air shocks will work great for rock crawlers but might not be a good idea for someone riding the trails all the time. The reason being that the air will get heated up and get very stiff ruining your soft side.

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