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DIfference between Gas or Oil shocks????

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Can Can, Apr 1, 2002.

  1. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    A buddy of mine claims that gas-charged shocks aren't as good as oil-charged shocks. I wasn't aware of any difference myself, but do the two different styles behave diferently??

    I hope I used the right term because for some reason oil-charged doesn't sound right..../forums/images/icons/tongue.gif
     
  2. DesertDueler

    DesertDueler 1/2 ton status

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    The oil shocks will give you a better ride than the Gas charged ones. Rancho 5000s are gas charged for instance. They are the stiffest shock out there. I run Doestech shocks on my Jimmy. They are oil charged and give it a much smoother ride. They dont force themselves back to full extension like gas shocks do. I run Ranchos on the BUrb because I tow, but hate the way it rides when I dont have a trailer on it.
     
  3. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    So basically an oil-charged shock will dampen road imperfections a little better? If that's the case why would anybody run gas shocks???

    The Rancho 9000 shocks are adjustable. From what I've read the 3rd notch is like the R5000s.........what the heck would the 5th notch feel like???
     
  4. DesertDueler

    DesertDueler 1/2 ton status

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    I would run gas shocks all the time, but when towing you want a really stiff shock as well to keep the tires on the ground. As for the 5th position it gives you the feel of a fork lift /forums/images/icons/smile.gif
     
  5. Hossbaby50

    Hossbaby50 3/4 ton status

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    My buddy has 9000's on his 66 Chevy Pickup, and when he turns them to 5 you know it. One time we had just got done hauling something heavy, and the shocks were still on 5, and we went threw a decent size dip in the and it put us both in the roof of the truck. His truck is even IFS front, and rides real nice, except when the shocks are set stiff.
     
  6. m j

    m j 1/2 ton status

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    gas charged shocks are merely pressurized oil shocks to prevent ?foaming? or ?cavitation?, sorry mental block for the word, when the oil is agitated.
    stiffness is in the valving
    gas charged is always better
     
  7. DesertDueler

    DesertDueler 1/2 ton status

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    MJ, thats why Prerunner trucks use oil shocks? And like I said I love the ride of my oil shocks versus the ride of my gas shocks.
     
  8. The_Sandman_454

    The_Sandman_454 1/2 ton status

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    Actually gas charged are the best and can be the stiffest or very stiff.

    Take the Bilsteins for example. They're *high* pressure gas charged shocks. To install them on my S truck (needed to be compressed) I had to use a ratchet strap and crank it in. Can't compress it unless you're leaning down hard on it and it's against the ground the other way.

    Gas charged prevent foaming and this is why you only see gas charged shocks used on pre runners, desert race vehicles, etc. The ride is a bit firm on the road but you have a *wonderful* amount of control. Amazing in fact...

    The Rancho 5k's lasted about a month before *all* dampening effects were *gone* in my S truck. Might as well *not* have even had shocks on there at all. Swapped a set of Bilstein HD's in there and there was an *amazing* difference in handling and control...

    I'm going to put a set of Bilstein HD's or 5100's in my solid axle suburban when I'm ready to get it back on (off) the road.... Will never touch a non gas charged shock again...
     
  9. m j

    m j 1/2 ton status

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    look again
     
  10. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    So for a stock(suspension-wise) 84 K5 that sees little offroad but lots of towing in the summer, would the Bilsteins be a good choice? Up here the shock of choice is Monroe - is there a specific model of Monroe shock that would be comparable to the Bilstein you guys are talking about???
     
  11. HarryH3

    HarryH3 1 ton status Author

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    All modern automotive shocks use some type of oil as the hydraulic damping medium. However, in hard use (pre-running and desert racing type stuff) the shock is moving so fast and so often that the oil starts to get air bubbles forming in it, known as foaming. Air will flow through the internal orifices of the shock MUCH quicker than oil would and the shock loses its ability to control motion. This is referred to as shock fade.

    Pressurizing the oil cavity greatly reduces the tendency for the air bubbles to form in the oil. What do they use for this "pressure"? A gas, typically nitrogen. Thus the term "gas shock". It still uses the damping oil to control motion, but the gas keeps the oil under high pressure to minimize shock fade.

    Desert racing trucks still have the problem of generating too much heat, as the physics of a shock absorber are to convert motion into heat. Hot oil gets thinner and loses viscosity, making it flow through the internal orifices quicker. Again, shock fade is the result. This is why you will see desert race trucks using huge shocks with remote oil resevoirs. More oil gives them a larger heat sink to dump the extra heat into. The remote resevoirs are usually finned, to dissipate even more heat. They also will often use multiple shocks for each wheel, to spread the heat across an even larger amount of fluid and cooling fin area. In the mulitple shock applications, each shock has to perform less work to control the same amount of motion, so they are valved much softer so that the truck doesn't ride like the axles are welded to the frame. /forums/images/icons/wink.gif
     
  12. RedDwarf

    RedDwarf 1/2 ton status

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    Think the term you are looking for is windage?

    Desert Dueler: I do not think the RS 5000 is a gas charged shock. The RSX is though
     
  13. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Sooooooooooooooo/forums/images/icons/crazy.gif...............could somebody answer my question? Would my stock 84 benefit from having one or the other? I tow a lot in the summer, BTW.
     
  14. m j

    m j 1/2 ton status

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    a gas pressurize shock is better
    Monroe and Gabrial are commonly available but I think the Bilstien are a better mono tube design or is that not the model you are looking at
     
  15. The_Sandman_454

    The_Sandman_454 1/2 ton status

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    I would say virtually *everything* would benefit from the gas charged shocks (like the Bilsteins)... Better handling, especially over rough terrain or rough roads, better control, as well as not fading anywhere *near* as fast as a non gas charged shock...
     
  16. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Thanks, Michael. For my application is there a certain model that I should consider? Around here the shock of choice is Monroe, although I;m sure I could get whatever I wanted in Calgary.

    Is the more $$$ Bilstein worth the extra bucks?
     
  17. m j

    m j 1/2 ton status

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    sorry, no help here
    I have been dreaming about rebuildable/revalvable shocks from the circle track catalogues
    the shock conversation has started here once before but no experts stepped up to give hard guidelines.
    I think shock gurus are rare
     
  18. HarryH3

    HarryH3 1 ton status Author

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    I've got Monroe Gas Magnum (or some name similar to that) /forums/images/icons/shocked.gif shocks on my S-Jimmy. They ride great and have held up for many years and over lots of washboard dirt roads. /forums/images/icons/cool.gif
     
  19. DesertDueler

    DesertDueler 1/2 ton status

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    Gas Charged if you tow. I just like the oil shocks on my Jimmy, because between the TF ez ride lift and the Doestech shocks I have a ride just as soft as the factory springs, and it rides like a caddy dwon washboard roads, even above 55 mph.
     
  20. Pugsley

    Pugsley 1/2 ton status

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    Correct - RS5000's are really hideously valved hydros. I run the Doetsch Prerunners which have nearly perfect valving for a mild K5, but might be a smidge soft for the 14bolt/38's+ crowd in a single shock application (lots of unsprung weight there). For towing with a stocker, I'd look at the Monroe gas mags, or Rancho 9000's.
     

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