Shock Therapy

[Bornindesert]

Was wanting to see how Comanche or Xj owners felt about shock absorber boots and orientation when there is a choice.

 

First is the front Billstein with the large unruly black boot. I'm not feeling the way the boot looks like the shock could be bent. Would you leave it or remove it?

 

 

Then the rear shocks would tend to mount reversed from the way I have them. I'm not sure if it makes a difference, although I like seeing the rod end down so someone trailing behind can spot an issue. Would like to know what opinions are out there for gas side on the top like mine or mounted down toward the axle end.

 

 

The axle mounts are Barne's 4x4.

[mvusse]

Depends on how the shocks have been designed internally to be mounted. I do not believe any shocks out there can be mounted either way and work correctly no matter which way they are oriented.

 

As far as boots go, they are designed to keep dust away. But if you take it through mud, or have a lot of rainy days driving it on a wet road, the boots are really good at trapping water and causing the shock to rust away faster than it normally would.

[nitroxsteve]

Depends on how the shocks have been designed internally to be mounted. I do not believe any shocks out there can be mounted either way and work correctly no matter which way they are oriented.

 

As far as boots go, they are designed to keep dust away. But if you take it through mud, or have a lot of rainy days driving it on a wet road, the boots are really good at trapping water and causing the shock to rust away faster than it normally would.

X2

[Eagle]

Depends on how the shocks have been designed internally to be mounted. I do not believe any shocks out there can be mounted either way and work correctly no matter which way they are oriented.

 

As far as boots go, they are designed to keep dust away. But if you take it through mud, or have a lot of rainy days driving it on a wet road, the boots are really good at trapping water and causing the shock to rust away faster than it normally would.

 

There are a VERY few that can be mounted either way, but not many. Usually the rod should go up, unless the instructions specifically say otherwise.

[HOrnbrod]

Some Bilstein shocks are mounted rod up, some rod down. Orientation depends on the logo and part number stamped on the shock body. According to Bilstein, the writing should be right-side-up and readable when mounted correctly and not upside-down, as in Bornindesert's Bilstein front shock pic above. Not any question on the front shocks as to orientation as the ends are different. Bilstein's 5100 series MJ rear shocks (both ends are eye ends) are mounted with the rod/boot on the bottom so you can read the writing on the shock.

[Bornindesert]

Goods inputs - thanks. Looks like I'll be reversing the rear shocks after I confirm with the product sheet on their web site.

[87mjdriver]

I hope this isn't considered a thread high jack, but here's my question concerning the above topic.

I have a 98 grand cherokee with a three inch pro comp lift, I talked to nick (aka Kolak) to get some better shocks.

He recommended Rubicon express mono tubes but he only found a set of them that we're designed for a TJ but the lengths worked.

 

I have the rears mounted boot down, is this correct???

[HOrnbrod]

I'd call Rubicon express with the shock p/n to be sure.

[Eagle]

I hope this isn't considered a thread high jack, but here's my question concerning the above topic.

I have a 98 grand cherokee with a three inch pro comp lift, I talked to nick (aka Kolak) to get some better shocks.

He recommended Rubicon express mono tubes but he only found a set of them that we're designed for a TJ but the lengths worked.

 

I have the rears mounted boot down, is this correct???

 

Probably not, but check with Nick or RE to be sure.

 

How is Nick? I haven't touched base with him for probably ten years or more.

[Bornindesert]

I upgraded my 2001 GC brakes through Kolak, made a huge difference in stopping power and here in Phoenix that's a big plus if you ride the freeways.

 

Sent an email to ProCompUSA will post when I hear back.

 

Since the shocks operate with gas, not fluid like the Oleos on an F/A18 Super Hornet I can't imagine why orientation would matter but I'm all ears.

[Eagle]

 

Since the shocks operate with gas, not fluid like the Oleos on an F/A18 Super Hornet I can't imagine why orientation would matter but I'm all ears.

 

The shocks operate with gas, not fluid? What kind of shocks do you have?

 

I don't think you understand what the term "gas shocks" means. Generally, all it means is that, instead of the non-fluid part of the interior of the shock being at atmospheric pressure, there is a chamber that is filled with a LOW pressure charge of inert gas, usually nitrogen. The gas doesn't do anything as far as absorbing shock. All it does is reduce the tendency of the hydraulic fluid to foam when it gets hot and works hard by raising the ambient pressure to which the fluid is exposed.

 

It's like taking a new bottle of cola and shaking it. As long as you don't open the cap, whatever pressure is in the bottle doesn't allow the carbonation gas to foam out. Open the cap, and you get LOTS of foam. We don't want foam in our shock absorbers.

 

The fluid in a shock absorber absorbs shocks by being forced through orifices and valves inside the shock. Not all shocks are designed and valved to resist movement equally in both directions. An extreme example is the 90/10 shocks used in the front of drag race cars. They allow lots of uplift, to help transfer weight to the rear wheels off the line, and they resist compression to help KEEP that weight on the rear wheels. Consider what would happen if they were mounted upside down.

 

Also consider that the valves in the shocks are designed to function when the shock is installed in the orientation the designer expects it to be installed. If you invert the shock, the valving may or may not (probably not) function as designed.

[Bornindesert]

Got it, thanks Eagle. It's gas over the working fluid, makes sense that orientation would matter. I still have not located the manufacturers recommended orientation for this shock, so have contacted them for an answer.

[87mjdriver]

^{Probably not, but check with Nick or RE to be sure.}

 

^{How is Nick? I haven't touched base with him for probably ten years or more.}

 

 

I haven't talked to him in a long time either, my jeep has always rode very rough, especially the rear, I was thinking maybe its the way the shocks are mounted now.

[HOrnbrod]

Probably not, but check with Nick or RE to be sure.

 

How is Nick? I haven't touched base with him for probably ten years or more.

 

Just talked to Nick last month. He got me an ADDCO MJ front sway bar at about 1/3 less than anywhere else I could find. He's doing fine and is still a great guy. Have known him for years too and was a lot of help finding the best header available at the time for Jeep I6 strokers.

[nitroxsteve]

 

Since the shocks operate with gas, not fluid like the Oleos on an F/A18 Super Hornet I can't imagine why orientation would matter but I'm all ears.

 

The shocks operate with gas, not fluid? What kind of shocks do you have?

 

I don't think you understand what the term "gas shocks" means. Generally, all it means is that, instead of the non-fluid part of the interior of the shock being at atmospheric pressure, there is a chamber that is filled with a LOW pressure charge of inert gas, usually nitrogen. The gas doesn't do anything as far as absorbing shock. All it does is reduce the tendency of the hydraulic fluid to foam when it gets hot and works hard by raising the ambient pressure to which the fluid is exposed.

 

It's like taking a new bottle of cola and shaking it. As long as you don't open the cap, whatever pressure is in the bottle doesn't allow the carbonation gas to foam out. Open the cap, and you get LOTS of foam. We don't want foam in our shock absorbers.

 

The fluid in a shock absorber absorbs shocks by being forced through orifices and valves inside the shock. Not all shocks are designed and valved to resist movement equally in both directions. An extreme example is the 90/10 shocks used in the front of drag race cars. They allow lots of uplift, to help transfer weight to the rear wheels off the line, and they resist compression to help KEEP that weight on the rear wheels. Consider what would happen if they were mounted upside down.

 

Also consider that the valves in the shocks are designed to function when the shock is installed in the orientation the designer expects it to be installed. If you invert the shock, the valving may or may not (probably not) function as designed.

 

Here is a link to monroe that explains a lot.

 

http://www.monroe.com/en-US/support/Technical-Training/Shock-Absorbers/

 

And when talking about mounting a shock upside down and changing the compression or damping I am confused. Here is my thinking... Install shock raise axle shock compresses. Remove and reinstall shock upside down raise axle and shock compresses. It seems to me the ratio would not change or am I not getting it?

[nitroxsteve]

Some how the quote got ran together sorry don't know how I did thsat. Lol

[SW86]

awesome on the shock tabs, i just bought the same ones to install. seems like they worked out good.

[Eagle]

 

And when talking about mounting a shock upside down and changing the compression or damping I am confused. Here is my thinking... Install shock raise axle shock compresses. Remove and reinstall shock upside down raise axle and shock compresses. It seems to me the ratio would not change or am I not getting it?

 

What you have just described doesn't say anything about a "ratio." Up is up, down is down. What "ratio"?

 

Do you understand that shocks have internal valves to control the fluid flow and velocity? That's what allows the shocks to do their job -- they restrict the flow of the hydraulic fluid, which restricts the movement of the suspension. Valving can be set to 50/50, which offers equal resistance to compression and extension, or it can be set to other ratios such as 60/40 or even (as in the drag race shocks) 90/10.

 

Take a 90/10 shock and mount it upside down, and now you have a 10/90 shock. Instead of allowing a lot of extension but little compression, it will now resist uplift, but if the front gets extended it will offer almost no resistance to compression.

 

And that still doesn't address the fact that some valves may be designed to operate in one orientation only, and won't operate properly when installed upside-down.

[Bornindesert]

Eagle, I'm realizing how much I didn't know about shock absorber design and application. Really appreciate the info and advice. All of the pictures that I've pulled up on ProComp 9000's would indicate they are installed tube down, rod up. I need to re-install mine this coming weekend so they work as intended.

 

We need to have a Shock 101 class here on CC lol.

[Bornindesert]

awesome on the shock tabs, i just bought the same ones to install. seems like they worked out good.

I was pleased with how they installed. Eventually I will remove the Chevy drop shackles and convert the D35 to SOA. The Barne's brackets are beefy mounts and you can lay a decent weld down so if they catch on something i think they would survive.

[nitroxsteve]

 

And when talking about mounting a shock upside down and changing the compression or damping I am confused. Here is my thinking... Install shock raise axle shock compresses. Remove and reinstall shock upside down raise axle and shock compresses. It seems to me the ratio would not change or am I not getting it?

 

What you have just described doesn't say anything about a "ratio." Up is up, down is down. What "ratio"?

 

Do you understand that shocks have internal valves to control the fluid flow and velocity? That's what allows the shocks to do their job -- they restrict the flow of the hydraulic fluid, which restricts the movement of the suspension. Valving can be set to 50/50, which offers equal resistance to compression and extension, or it can be set to other ratios such as 60/40 or even (as in the drag race shocks) 90/10.

 

Take a 90/10 shock and mount it upside down, and now you have a 10/90 shock. Instead of allowing a lot of extension but little compression, it will now resist uplift, but if the front gets extended it will offer almost no resistance to compression.

 

And that still doesn't address the fact that some valves may be designed to operate in one orientation only, and won't operate properly when installed upside-down.

I understand the valving and understand that not all shocks can be mounted in both directions but some can. And I am not talking about the op shocks. I just posted a link that explains different shocks that I thought may help. My question about the ratio changing my not have been clear. In my mind if I look at a 90/10 drag shock lots of extension verry little compression. If this shock is of a style that can be mounted in both directions the ratio will not change because its always extending when the car launches no matter the orientation. Now if you put the shocks on the back of the car that would cause a problem. Or I could be nuts sorry I took it off topic.

[Eagle]

I understand the valving and understand that not all shocks can be mounted in both directions but some can. And I am not talking about the op shocks. I just posted a link that explains different shocks that I thought may help. My question about the ratio changing my not have been clear. In my mind if I look at a 90/10 drag shock lots of extension verry little compression. If this shock is of a style that can be mounted in both directions the ratio will not change because its always extending when the car launches no matter the orientation. Now if you put the shocks on the back of the car that would cause a problem. Or I could be nuts sorry I took it off topic.

 

Actually, you're right. Extension is still extension. My bad.

 

However, there is still the issue that the valves may not work properly (or at all) if/when inverted.

[Bornindesert]

Well flipped the rear shocks today, and had a good laugh. Look what was right on the shock!! Yup.

 

[Eagle]

That there is what we call a "clue." :doh: