another rookie question: shock travel?

How do you know how much travel you need when buying shocks for a vehicle where the shock mounts have been modified and the vehicle has been lifted?

94XJ4x4 said:

How do you know how much travel you need when buying shocks for a vehicle where the shock mounts have been modified and the vehicle has been lifted?

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Compress one side fully, take a measurement between shock mounts.
Extend the same side fully, take a measurement between shock mounts.

Take these measurements to your nearest shock seller.

Get a shock in these dimensions.

Okie Terry said:

Compress one side fully, take a measurement between shock mounts.
Extend the same side fully, take a measurement between shock mounts.
Take these measurements to your nearest shock seller.
Get a shock in these dimensions.

Click to expand...

this seems to be an over-simplification...
then again, i might just be making this harder than it needs to be (i'm in the same boat this weekend, trying to determine proper shock lengths). :wierd:

if i'm not mistaken, you need to also take into account the static ride height measurement as well as the bump stop lengths.

otherwise you may be severley limiting compression and/or droop, especially w/ modified shock mounts, even if you have shocks of the correct length.
worst case: you destroy a new shock by using it as the bumpstop or droop limiter.

i'm racking my brain looking over all of these spec charts trying to find the best fit.

(to make matters worse, you can throw in BPEs and shock adapters into the equation!)

terry

MMIXJ said:

this seems to be an over-simplification...
then again, i might just be making this harder than it needs to be (i'm in the same boat this weekend, trying to determine proper shock lengths). :wierd:

if i'm not mistaken, you need to also take into account the static ride height measurement as well as the bump stop lengths.

otherwise you may be severley limiting compression and/or droop, especially w/ modified shock mounts, even if you have shocks of the correct length.
worst case: you destroy a new shock by using it as the bumpstop or droop limiter.

i'm racking my brain looking over all of these spec charts trying to find the best fit.

(to make matters worse, you can throw in BPEs and shock adapters into the equation!)

terry

Click to expand...

it is as simple as okie posted. as long as your bumpstops, bpe's and shock mounts are all setup correctly when you measure for shocks, all those factors will be included when you measure extended and compressed length.

so yes, you are making it harder than it needs to be

it must be the BPE and/or shock adapter that is confusing me then...

perhaps you can advise me (hopefully the slight hijack will help 94XJ4X4 and others):

my current front shock mounts are stock (i.e. stud on top, bar pin below).
i pulled the shocks up front and took some measurements:
23" static, 19" compressed, 30" extended = 11 inches travel, 4" up, 7" droop.

according to the rancho 9000 specs, they don't make a 30"+ shock w/ a stud on top.
so if i run the shock adapter for the upper mount, i effectively lose 1.5" of length, right?

so now my static would be 21.5", (minus the 4" compression window 'til bumpstops)
for 17.5" compressed length, and extended length would be 28.5.

or i suppose i could go the other direction and keep the stud and get the BPE
for the lower mount so now my static is 22", 18" compressed, 29" extended.

in the former case looks like the closest fit would be a #99273 (16.87"/28.125"), but
would be shock limiting.

in the latter case looks like the closest thing i could run is a #99238 (17.25"/28.625),
but then i'm still shock limiting.

:wierd: all of these numbers are making me crazy!! ...any thoughts?

thanks.

I wouldnt base my #'s on the shocks your running now unless they are already perfectly sized to your lift!As already stated by "Okie",you have to cycle the suspension after all the BPE,bumpstop,mount location mods!

MMIXJ said:

it must be the BPE and/or shock adapter that is confusing me then...
perhaps you can advise me (hopefully the slight hijack will help 94XJ4X4 and others):
my current front shock mounts are stock (i.e. stud on top, bar pin below).
--i pulled the shocks up front and took some measurements:
23" static, 19" compressed, 30" extended = 11 inches travel, 4" up, 7" droop.
--according to the rancho 9000 specs, they don't make a 30"+ shock w/ a stud on top.
so if i run the shock adapter for the upper mount, i effectively lose 1.5" of length, right?
--so now my static would be 21.5", (minus the 4" compression window 'til bumpstops)
for 17.5" compressed length, and extended length would be 28.5.
--or i suppose i could go the other direction and keep the stud and get the BPE
for the lower mount so now my static is 22", 18" compressed, 29" extended.
--in the former case looks like the closest fit would be a #99273 (16.87"/28.125"), but
would be shock limiting.
--in the latter case looks like the closest thing i could run is a #99238 (17.25"/28.625),
but then i'm still shock limiting.

Click to expand...

All those numbers are crazy-making to me too
Try this:
Install BPEs on uppers and lowers. Either aftermarket or make your own. BPE's will greatly increase the variety of shocks available to you. After installing BPE's, cycle your suspension and measure the distance between the BPE's fully extended and fully compressed. Don't worry about the static height, it should be accounted for by the full extension and compression measurements. Next, buy a shock that fits your fully extended and compressed measurements. Next, install the shocks and take measurements under compression so that the shock is almost fully compressed, then adjust your bumpstops so that they prevent the shock from fully compressing as that will damage your shock. I'm not sure what you meant by "shock limiting" in your post, but no harm will come to your shocks from them acting as extension limiters. Double check to make sure your brake lines don't inadvertently become the extension limiters! Hopefully this all makes sense. It's a pretty simple process; it seems like you are cluttering it up with unecessary calculations and measurements. Good luck.
B.

What is static height? The shock lenght at normal ride height?

RCP Phx said:

I wouldnt base my #'s on the shocks your running now unless they are already perfectly sized to your lift!As already stated by "Okie",you have to cycle the suspension after all the BPE,bumpstop,mount location mods!

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those numbers were taken w/ the shocks disconnected... cycling the suspension.

and in theory i know the lengths of the BPEs and shock adapters, so i should be able to just factor those in before purchasing anything.

94XJ4x4 said:

What is static height? The shock lenght at normal ride height?

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yep, sitting flat in the garage. from my understanding it is important because it will tell you how much of the travel is going to be either up or down.

:dunno:

Why is this so hard to figure out? Just take the measurements and bring it to the local shock dealer and give it to them. They will get you what you need. Your over thinking. It's quite simply.

hmmm... beej i think you're putting the cart before the horse!

you should bump stop to protect springs and fenders and such and then buy shocks accordingly, at least i would think.

Beej said:

All those numbers are crazy-making to me too
Try this:
Install BPEs on uppers and lowers. Either aftermarket or make your own. BPE's will greatly increase the variety of shocks available to you. After installing BPE's, cycle your suspension and measure the distance between the BPE's fully extended and fully compressed. Don't worry about the static height, it should be accounted for by the full extension and compression measurements. Next, buy a shock that fits your fully extended and compressed measurements. Next, install the shocks and take measurements under compression so that the shock is almost fully compressed, then adjust your bumpstops so that they prevent the shock from fully compressing as that will damage your shock. I'm not sure what you meant by "shock limiting" in your post, but no harm will come to your shocks from them acting as extension limiters. Double check to make sure your brake lines don't inadvertently become the extension limiters! Hopefully this all makes sense. It's a pretty simple process; it seems like you are cluttering it up with unecessary calculations and measurements. Good luck.
B.

Click to expand...

Markus said:

Why is this so hard to figure out? Just take the measurements and bring it to the local shock dealer and give it to them. They will get you what you need. Your over thinking. It's quite simply.

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well i'm willing to accept that if somebody can actually explain it more thoroughly...

think of it this way: the bigger tire you run the more bumpstop you need to keep the tire out of the fender.

so say you have (for the sake of easy math) 10" compressed and 20" extended for 10" of travel--
if your static height is 15 then you have 5 up and 5 down. but a guy w/ bigger tires can't actually use all 5" uptravel,
cuz he's got to bumpstop at say 3". but if his static height is say 17" then he's golden: 3 up 7 down nothing wasted.
likewise if you add BPEs/adapters you're either compressing the shock more (relatively speaking) or using a shorter shock.

so it still seems to me that you can't just simplify it by saying "take 2 measurements and go to the shock dealer"...

if i'm wrong, please elaborate-- i'm hoping i am wrong, cuz it does seem harder to figure than it should.
but something tells me there are a lot of lifted rigs out there w/ less than ideal shocks.

fwiw, i'm gonna call rancho tomorrow and have them school me. :cheers:

When you're done making this a trig. problem, just refer to the 2nd post.

MMIXJ said:

hmmm... beej i think you're putting the cart before the horse!
you should bump stop to protect springs and fenders and such and then buy shocks accordingly, at least i would think.

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Terry's already said it best, twice. Adjustment of bumpstops is for all of these reasons: to protect your fenders/keep your tires off your body/keep your shocks from compressing fully and in the rear its also to prevent your springs from having to flex too far. They are all good reasons. My post was offered as a proven method for obtaining shocks that will cycle and perform well according to the specifics of your vehicle, and a method for setting them up. I have done this on my own jeep and noted that no other measurements were needed aside from maximum stuff and maximum droop. Check out this page, there is some good information.