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  1. #1
    CO Scramble Host 1BADCJ8's Avatar
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    Shocks... Up or Down???

    Why do some people run there shocks up side down with the rods pointed down versus running them with the tubes down?

    I've wondered this for a while and best I can think is that it gives more room at the bottom and you don't get the "U-Bolt plate dent" in them. Hold any water?

    Is there any difference as far as weakness or strength?
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  2. #2
    otisdog's Avatar
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    Some shocks can be run can-up and some can't. Mine are MX6's and they are designed to run can-up. Monotubes can be mounted either way I believe.
    One advantage at least for TJ's is that when you do an SYE/CV conversion generally you have to rotate the pinion up so it points straight at the t-case. Since the shock mounts are on the back of the axle it rotates them down and moves the shocks closer to the axle tube. If the cans are down they will hit the axle tube under flex. Two ways to cure this are mount the shocks can-up if possible or get shock mount extenders which throws the mounts out farther and makes them more vulnerable to getting tore off.
    Jim
    Last edited by otisdog; September 11th, 2011 at 04:19 PM.
    03 TJ auto, 4" Mixed lift, 33 BFG KM2's, D44 locked/D30, Warn x8000i and some other junk

  3. #3
    ROCK BRAWLER's Avatar
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    Hydraulic shocks have to be mounted with the can on the bottom but nitrogen charged can go either way
    Captain Mayhem-
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  4. #4
    Bilstein 5125's are can up.
    1984 Toyota 4Runner

    [QUOTE=CGuava]I might be brown, but my neck is red on the inside![/QUOTE]

  5. #5
    newracer's Avatar
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    Quote Originally Posted by otisdog View Post
    Some shocks can be run can-up and some can't. Mine are MX6's and they are designed to run can-up. Monotubes can be mounted either way I believe.
    One advantage at least for TJ's is that when you do an SYE/CV conversion generally you have to rotate the pinion up so it points straight at the t-case. Since the shock mounts are on the back of the axle it rotates them down and moves the shocks closer to the axle tube. If the cans are down they will hit the axle tube under flex. Two ways to cure this are mount the shocks can-up if possible or get shock mount extenders which throws the mounts out farther and makes them more vulnerable to getting tore off.
    Jim
    Or outboard the shocks.
    Have you ever seen a man eat so much fish?

  6. #6
    otisdog's Avatar
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    Quote Originally Posted by newracer View Post
    Or outboard the shocks.
    Yep -didn't think of that one.
    jim

  7. #7
    Like mentioned, some shocks can be mounted can-up (either way), while others its better if they are not (or you'll cause internal component damage if you do), while others its required for them to be mounted can-up.

    For the most part - hydraulic shocks (those without gas inside) need to be mounted can- down. If you mount them can-up, they will eventually fade causing the initial first movement of the shock to be far less effective. Usually the seals will start to loose their effectiveness and you may get some leaks and then air gets sucked into the chamber causing an even less effective shock control.

    For emulsion shocks (like Fox emulsion shocks which are nitrogen charged), its generally a requirement that they are mounted can-up. If you don't, you'll starve the seal of the floating piston, but keeping them mounted can-up keeps the seal flooded at all times.

    In the emulsion style or reservoir style shocks, the gas is necessary and shouldn't mix with the oil. Keeping it seperated allows for a more uniform/balanced dampening characteristic. Plus, the gas is necessary to allow space displacement as the shock shaft enters the shock body.

  8. #8
    ROCK BRAWLER's Avatar
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    I replaced the rear gas charged shocks once on my jeep with some cheapy hydraulic ones and the previous were mounted can-up. So I put the hydraulic ones that way too and everytime I hit a bump i would get this LOUD thumping noise. A mechanic friend told me that if the hydraulic shocks are mounted upside down it messed with the flow so to speak so they were acting as if they were bottoming out on every bump

  9. #9
    CO Scramble Host 1BADCJ8's Avatar
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    Yep I did some looking around and have found most of what you guys are saying as well. My main question, in my head, was; Does it benefit anything.

    None-the-less, I was wondering simply because I have so Rancho RS9000's that I'm going to be putting on my Jeep and wondered if they would could go can up and if there was a benefit to it. From what I have found some do run these can up but most say its not good for them and Rancho doesn't return emails so I'll just run them Can Down and be done.

    Thanks for the input fellas...

  10. #10
    The RS9000's are fine to run can up (this is coming from somebody who use to work for Rancho and use to build shocks from scratch for a living).

  11. #11
    CO Scramble Host 1BADCJ8's Avatar
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    E-mail reply from Rancho...

    RanchoExtreme Team


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    From: Robert Johnson (rjohnson@tenneco.com) on behalf of RanchoExtreme Team (RTeam@Tenneco.com)
    Sent: Wed 9/14/11 2:12 PM
    To: onebadcj8@msn.com

    Thank you for your interest in Rancho products.

    No, they can not be mounted upside down, as the shock will not function.

    For further questions or assistance, please contact technical assistance at 734-384-7804 M - F 8:30am - 5:30pm EST.

    Rancho Team Member,

    Rob

  12. #12
    Chris Overacker's Avatar
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    I once heard a shock MFG. say, "it is better to move the piston inside the cylinder, than to move the cylinder around the piston".

    So, that may be one reason that the better shock MFG's mount them can-up, rod down (since the piston is connected to the rod).

    Most good shocks (all?) have gas pressure. This eliminates any air in the shock. Most hydraulic (non-gas) shocks have an air pocket which allows for fluid expansion. When a non-gas shock is mounted can up, the air pocket rises to the top, thus the valving which is now at the top is exposed to the air pocket. The valves need oil, not air to function.
    Hope this clears things up.
    Put a little gravel in your travels, take a back road!

  13. #13
    CO Scramble Host 1BADCJ8's Avatar
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    Sure that makes sense Chris...

    I got them used from a friend that went Coilover, they are 14in travel and even adding towers they are a little tall. After I was done with the towers/hoops they would actually be perfect for 12in of travel. I've only got 5.5in of up travel as it turns out with these but with the 42' MT/R's I hit fender before that.

    Any way, I just went ahead and mounted them the regular 'ole way. Even used I don't want to ruin them.

  14. #14
    Quote Originally Posted by 1BADCJ8 View Post
    RanchoExtreme Team


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    To onebadcj8@msn.com
    From: Robert Johnson (rjohnson@tenneco.com) on behalf of RanchoExtreme Team (RTeam@Tenneco.com)
    Sent: Wed 9/14/11 2:12 PM
    To: onebadcj8@msn.com

    Thank you for your interest in Rancho products.

    No, they can not be mounted upside down, as the shock will not function.

    For further questions or assistance, please contact technical assistance at 734-384-7804 M - F 8:30am - 5:30pm EST.

    Rancho Team Member,

    Rob
    Do you know specifically if they were aware you were asking about the RS9000's (not the RS9000XL's) or basically the RS's that replaced them?

    I ask because from what I understand the RS9000's are no longer made/available unless somebody has some really old stock laying around.

    I ran RS9000's for ~6 years with zero issues knowing the RS9000's can be ran either way.
    Last edited by Joe Dillard; September 21st, 2011 at 11:33 AM.

  15. #15
    Barf Bag's Avatar
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    Quote Originally Posted by Chris Overacker View Post
    I once heard a shock MFG. say, "it is better to move the piston inside the cylinder, than to move the cylinder around the piston".
    makes no sense. how do they figure which one is moving and which is not when a moving vehicle with a cycling suspension is a complex dynamic situation.
    [QUOTE=Snotty;1352791]The government didn't fail those people. Darwin did.[/QUOTE]

  16. #16
    Chris Overacker's Avatar
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    Quote Originally Posted by Barf Bag View Post
    makes no sense. how do they figure which one is moving and which is not when a moving vehicle with a cycling suspension is a complex dynamic situation.
    If I have to explan it more, you wont understand.

  17. #17
    crashXJ's Avatar
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    My monotube Bilsteins are mounted with the tube on top. Even if I wanted tube on the bottom I would not be able due to the aftermarket TnT brackets I am using as the tube would hit the bracket and potentially cause a failure in the shock.
    This is my boom stick.

  18. #18
    CO Scramble Host 1BADCJ8's Avatar
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    Quote Originally Posted by Joe Dillard View Post
    Do you know specifically if they were aware you were asking about the RS9000's (not the RS9000XL's).
    Yes I was very specific that they are RS9000's... Look above, I stated I got them used, you are right, they only have the XL's now. I read a bunch on many different forums and on all of them pretty much found what Chris stated here. However there were some that said they ran theirs can up with never an issue. I originally just wanted to know if there was a benefit to to it one way or the other. In the end I just welded on my towers and bolted them on, wala all done .

  19. #19
    Hi all,

    Just to let you guys know, I have the Procomp ES3000 shocks on my rig. I mounted them with teh can up and the ride was horrible and felt soft. It also made a lot of unfamilar noise. I contacted Procomp and they said the cans had to be in the downward position to work properly. I changed the orientation of the shocks with the can down and they feel perfect now. Much better rebound and compression dampening. The noise is gone too.

    I can copy in the text of the email if anyone is interested.

    Rob

  20. #20
    Barf Bag's Avatar
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    Quote Originally Posted by Chris Overacker View Post
    If I have to explan it more, you wont understand.
    There is no understanding the retarded statement that shock manufacturer made. The system will not notice which one is moving in space because the only movement it notices is what is going on inside the shock, the piston moves relative to the cylinder or the cylinder moves relative to the shock, same thing.

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