Extension of a shock absorber with no load on vehicle (at rest)??

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AlexK10

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Hi, Im in the process of dealing with the rear shock mounts on my K10. I have currently the stock shocks with a 2" lift block.

I have a plan to relocate the top shock attachment point to avoid the elongated stud hole in the frame and future frame cracks.

Before I go any further I need to know what is the recomended "no load on vehicle" shock compression % or lenght, given the designed travel of the shock (or any shock for that matter).

Lets say my shocks travel 9.36 inches and this is at 100% extension. Should these be mounted at full extension or how much extended when vehicle is at rest? 8", 7" ...

Any ideas?
 

78C10BigTen

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Not technical at all but when i added 3" blocks to my suburban rear i took off the shock and had the auto store match it but be 3" longer at full extension. Turns out they were for the same year truck (not suburban) just a 3500 not a 1500. But i was like 20 so i did it a little cockamayme... i threw blocks in the rear and cranked the tortions in the front to put 33s on it. Needless to say i got yelled at by the alignment shop to never turn up tortion bars... but i ran them new 33s till they were bald without incident so...:shrug:
 

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It’s kind of specific to each application. Jack up one side of the frame so the wheel comes off the ground on the one side and the other side tucks in, try to get the side on the ground as tucked in as possible, don’t kill yourself though. Then take the measurements from center to center of shock mounts, one side will be full extension length and one side will be compressed length, measure at normal ride height as well.

Then you have your specs, make sure you have a couple extra inches extra or so, so you don’t blow up a shock
 

77 K20

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Offroaddesign has a page that shows recommended "generic" shock lengths.

http://offroaddesign.com/catalog/Bilstein 5125.htm

For a 3" lift in the rear they show a 11" shock.

If you bolt on a shock when it is near full extension then when lets say you hit a speed bump fast- after the initial compression then it will extend fast- and will try to pull the shock apart. Shocks don't like this for long. Its better to be towards the middle of the travel.
 

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It’s kind of specific to each application. Jack up one side of the frame so the wheel comes off the ground on the one side and the other side tucks in, try to get the side on the ground as tucked in as possible, don’t kill yourself though. Then take the measurements from center to center of shock mounts, one side will be full extension length and one side will be compressed length, measure at normal ride height as well.

Then you have your specs, make sure you have a couple extra inches extra or so, so you don’t blow up a shock
Oh an air lift bumper jack..... heaven...
 

shiftpro

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[QUOTE="78c10bigten, post: 458602, member: 1329 cockamayme... [/QUOTE]

bassackwards
 

AlexK10

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Thank you all for the suggestions.

Additional info: I do not do any rock crawling or heavy off-roading, its basically a home use work truck to carry stuff (move small equipment, construction lumber, pipe, rebar, concrete bags and block, landscaping materials). For whatever I need to move around and not use my daily driver suv.

I can definitely jack one side up and figure out full extension and compression of the suspension and go from there.

Hypothetical scenario: (Don't know if this will happen but) If it turns out that at full extension the current shock mounts are further away than the max shock length; or at full compression the current shock mounts are closer than minimum shock length...

Option one: Try to find shocks that fall within this range. If not feasible go to option two.
Option two: Move shock mounts at full shock extension (or x inches below full extension) so that during compression the shocks do not bottom out, providing more down travel?

We all know its not rocket science but then again your opinions will make me feel better on where I locate the top mount.
 

AlexK10

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Thank you all for the suggestions.

Additional info: I do not do any rock crawling or heavy off-roading, its basically a home use work truck to carry stuff (move small equipment, construction lumber, pipe, rebar, concrete bags and block, landscaping materials). For whatever I need to move around and not use my daily driver suv.

I can definitely jack one side up and figure out full extension and compression of the suspension and go from there.

Hypothetical scenario: (Don't know if this will happen but) If it turns out that at full extension the current shock mounts are further away than the max shock length; or at full compression the current shock mounts are closer than minimum shock length...

Option one: Try to find shocks that fall within this range. If not feasible go to option two.
Option two: Move shock mounts at full shock extension (or x inches below full extension) so that during compression the shocks do not bottom out, providing more down travel?

We all know its not rocket science but then again your opinions will make me feel better on where I locate the top mount.
 

77 K20

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Instead of moving your upper shock mount I have seen where people have welded a thick washer up there to make it round again, or to fix cracks.

Then ORD makes a bracket to help support it.

Just an idea.

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