long travel shocks, who makes em (13"+travel)

BigSouth said:
... and what science keeps this from buckling under side load pressure? The forces applied aren’t always linear straight up and down.
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Duh.
The science of metals, duh!
 
BigSouth said:
... and what science keeps this from buckling under side load pressure? The forces applied aren’t always linear straight up and down.
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It's got pivots at both ends, so there shouldn't be much side force, except from something like binding bushings or the damping force trying to buckle it linearly. But the shaft velocity is divided roughly in half between the two shocks, so the linear damping force is half as much, so that will help with buckling.
 
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Fabrik8 said:
It's got pivots at both ends, so there shouldn't be much side force, except from something like binding bushings or the damping force trying to buckle it linearly. But the shaft velocity is divided roughly in half between the two shocks, so the linear damping force is half as much, so that will help with buckling.
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Sounds like you’ve got more confidence in this setup than I do. I see the transition from full droop to full bump at any rate of speed folding that thing in half right where it’s cobbled together.
 
I tried to type a response to this but have stopped backspaced it several times. It obviously works for now but only time will tell. My questions...why not mount the superduty shocks to your lowers? why do you need that much travel? Do you know that traction and performance will suffer greatly when you're that far out of your coil range? Are you going to weld stock xj coils together?

Have fun a carry on.
 
1stgenxxx said:
I tried to type a response to this but have stopped backspaced it several times. It obviously works for now but only time will tell. My questions...why not mount the superduty shocks to your lowers? why do you need that much travel? Do you know that traction and performance will suffer greatly when you're that far out of your coil range? Are you going to weld stock xj coils together?

Have fun a carry on.
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Hey quit trying to being logic in this discussion, that's not how things roll in this joint.
 
BigSouth said:
Sounds like you’ve got more confidence in this setup than I do. I see the transition from full droop to full bump at any rate of speed folding that thing in half right where it’s cobbled together.
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The failure would be the metal bending where it is welded. My guess is that a shock shaft will bend first.

But if you have nothing in the setup, and it works enough for you, and you dont care if you have to throw another set together if it breaks; why should the rest of us care too much? Roll cage or safety items, I understand.
 
BigSouth said:
Sounds like you’ve got more confidence in this setup than I do. I see the transition from full droop to full bump at any rate of speed folding that thing in half right where it’s cobbled together.
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I totally agree; the buckling forces should be in a straight line though, which was my point (it will bend when it fails though, obviously). Those shock eyes were not really meant to be used in bending, because they normally have a bushing to take care of that (normally tension and compression only), so it may be interesting to see what happens at that point when there is a bending/buckling load in the middle.

I'm not confident in the setup, just noting that the setup will cut the damping velocity in half-ish, so that may save the entire setup from failing.
 
Fabrik8 said:
I'm not confident in the setup, just noting that the setup will cut the damping velocity in half-ish, so that may save the entire setup from failing.
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do you mind elaborating on this, being honest, for my learning purposes. I'm trying to understand the physics here but sorry I'm slow.
 
marty79 said:
do you mind elaborating on this, being honest, for my learning purposes. I'm trying to understand the physics here but sorry I'm slow.
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Those shocks are designed to work at 1:1 motion ratio.

Think 1” of wheel travel equals 1” shock travel at the same velocity.

Because you mounted them in series,

1” of wheel travel equals .5” in one shock and .5” in other shock, the piston speed in the shock is now at 1/2 the speed of the wheel.

That is all theoretical. Bc the shock with firmer valving will move less, and make the other move more, until that valving starts to resist movement and make the other shock work again.

This switching between which shock is resisting movement, would oscillate back and forth less and less until no more suspension movement.

Going to have some weird characteristics for sure. You may not notice bc you are moving them at 1/2 the speed they are designed.
 
Mac5005 said:
Those shocks are designed to work at 1:1 motion ratio.

Think 1” of wheel travel equals 1” shock travel at the same velocity.

Because you mounted them in series,

1” of wheel travel equals .5” in one shock and .5” in other shock, the piston speed in the shock is now at 1/2 the speed of the wheel.

That is all theoretical. Bc the shock with firmer valving will move less, and make the other move more, until that valving starts to resist movement and make the other shock work again.

This switching between which shock is resisting movement, would oscillate back and forth less and less until no more suspension movement.

Going to have some weird characteristics for sure. You may not notice bc you are moving them at 1/2 the speed they are designed.
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ok I'm following now, makes sense thank you for that explanation
 
1stgenxxx said:
.why not mount the superduty shocks to your lowers? why do you need that much travel? Do you know that traction and performance will suffer greatly when you're that far out of your coil range? Are you going to weld stock xj coils together?
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as mentioned earlier I didn't think about that lol, it's def an idea for future reference when this setup fails lol.
As for "why the need" for long travel?...you say traction will suffer...so check this out
With a tire hanging in the air, you have 0 traction period! can't argue that "science of metals" LMBO
so even with spring unloaded, why not have that tire touching ground with the opposite axle side providing some force downward plus the weight of the axle and tire itself...now you're not only possibly gaining a little traction but MOST IMPORTANTLY staying planted, which means Stability!! You and others might not care to be all that stable but that's a big factor for my rig, and basically slowly figuring out how to achieve the closest I can without 2K coilovers lol, for now anyways
 
marty79 said:
With a tire hanging in the air, you have 0 traction period! can't argue that "science of metals" LMBO
so even with spring unloaded, why not have that tire touching ground with the opposite axle side providing some force downward plus the weight of the axle and tire itself...now you're not only possibly gaining a little traction
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Its a little more complex than that and will depend on specific location and other factors, but...with a properly setup suspension if one tire on a solid axle is in the air it is providing down force (through the magic of gravity) to the tire on the other end of that axle. Assuming you have a locker or welded rear then the total weight of the rig and whatever downforce this is is applied to the contact patch of that one tire which is spun by whatever horsepower/torque you have.
By going super long travel you allow the other tire to droop and (hopefully) contact the ground. This removes some force from the original tire and adss some to this new tire which is no longer floating in the air. But now you have two tires each with less force on them than the prior 1 tire.

Now if in the initial scenario you were able to transmit 100% of available HP to that single tire but not able to move, but doubling the contact patch and removing some weight this might solve the problem.
However if in the old scenario that single tire would spin and lose traction before movement occurred, you have actually potentially made the problem worse and both tires will now spin as each has less force on it.

Again there isnt a universal there are some scenarios where more contact patch is better and some where its not.

However I would definitely disagree with you regarding stability. More droop will me more body roll which will increase cab angle relavtive to ground position and actualy make you "Feel" more off camber
 
Ron said:
However I would definitely disagree with you regarding stability. More droop will me more body roll which will increase cab angle relavtive to ground position and actualy make you "Feel" more off camber
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Well dang, is that "just a feel" thing of more instability or are you saying it actually makes it more unstable? New concept to me
The rest of what you said is definitely a good point too, nothing is perfect setup I just prefer long travel for the type of wheeling I try and desire to do.
 
Some of y'all never seen a dude run shockles before, have you?
Guy wanted more droop in his Toyota rear suspension. Removed shackles, replaced them with 2 12" travel shocks in between the leaf and hanger (2 per side). Had impressive droop until it grenaded the driveline and rear output. Oh and it was crazy unstable.
This has zero to so with the subject at hand, just brought back a funny memory.
 
Stuntman Autoworks said:
I havent replied to one of your threads lately but I'm really surprised that you actually believe you do any wheeling that is more difficult, or any different from anyone on here that is giving you advice and trying to help you.
Your delusions of granduer are astonishing.
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Ok fair enough lol. I'm not saying I do. I like flexing on stuff, driving through big deep ravines and on that stuff I like the long travel and the looks of it. Now driving through a deep ravine without enough flex doesn't work out too well, at least not for my liking so that's when I got more into longer travel suspension
 
Why not just run Dual Shocks, Double up the shocks as fabricated now. Then dampening rates are back to where the originals (one) were. Then you can run whoops at 80MPH Throw back to the 80's :D
What could go wrong, I'd run it.:eek:
@marty79 I have to give you credit for ingenuity!
 
No fries said:
Why not just run Dual Shocks, Double up the shocks as fabricated now. Then dampening rates are back to where the originals (one) were. Then you can run whoops at 80MPH Throw back to the 80's :D
What could go wrong, I'd run it.:eek:
@marty79 I have to give you credit for ingenuity!
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Good thought,

But since we are trying explain things to fuller,

That’s not how shocks work.

They are velocity sensitive.

So even adding double the long shocks he has now, they are still operating at 1/2 the piston speed. Yes you would get 2x the damping/dampening force as there is currently, that still may be less than the shocks at 1x the designed piston speed.

The same is true if the put the shocks on the links, as the piston speed is slower than axle speed, but they wouldn’t need to be mounted at 1/2 the link length.

Hence why running trailing arm suspension has advantages and disadvantages. That slower piston speed can be tuned for with tuneable shocks.

Plus mounting them to the links wouldn’t have the weird oscillation between which of the two shock pistons is moving.


I still say run it until it fails and then do something else. At least you collect data and understanding in your experiment @Marty
 
Mac5005 said:
That’s not how shocks work.

They are velocity sensitive.

So even adding double the long shocks he has now, they are still operating at 1/2 the piston speed. Yes you would get 2x the damping/dampening force as there is currently, that still may be less than the shocks at 1x the designed piston speed.
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4dmdj9.jpg
 
Mac5005 said:
still say run it until it fails and then do something else. At least you collect data and understanding in your experiment @Mart
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That's what I'm all about, to some extent lol
 
Mac5005 said:
They are velocity sensitive.

So even adding double the long shocks he has now, they are still operating at 1/2 the piston speed. Yes you would get 2x the damping/dampening force as there is currently, that still may be less than the shocks at 1x the designed piston speed.
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Yeah, it's not easy to calculate unless you have the force-velocity plots for the damper, because the damping coefficient isn't linear with velocity. If it was linear with velocity, the damping coefficient actually combines in series like the spring rate of springs in series. It still combines like that when it's not linear, but you've have to calculate the resultant curve versus velocity for the combined velocities (because the damping coeffs are different at each velocity point). Basically you can't just say that the damping force is 1/2 because the velocity is 1/2 (I did make that oversimplification earlier in the thread).

All you can really know(without that) is that the velocity is roughly 1/2 depending on how the shocks are matched, so however the damping coeffs will combine at 1/2 velocity.
 
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Fabrik8 said:
Yeah, it's not easy to calculate unless you have the force-velocity plots for the damper, because the damping coefficient isn't linear with velocity. If it was linear with velocity, the damping coefficient actually combines in series like the spring rate of springs in series. It still combines like that when it's not linear, but you've have to calculate the resultant curve versus velocity for the combined velocities (because the damping coeffs are different at each velocity point). Basically you can't just say that the damping force is 1/2 because the velocity is 1/2 (I did make that oversimplification earlier in the thread).

All you can really know(without that) is that the velocity is roughly 1/2 depending on how the shocks are matched, so however the damping coeffs will combine at 1/2 velocity.
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My 1/2 was an over simplification for the sake of explanation. I guess I should have put that disclaimer on that post. It wasn’t meant to be taken as literally .5, more of a generic half.

I’m not a betting man, but if I were,

I’d bet those shocks are progressive and are designed for much higher piston speeds than most Offroad shocks due to being enginerded for a street use truck.

So they are already being used at too slow of a piston speed for the application, before mounting them in series.
 
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