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static ride height relative to shock travel

tdr1213

NAXJA Forum User
Location
Seattle
Is there a best case scenerio for static ride height relative to the shocks? What is the optimum as a percentage of compression vs droop? For example, at static ride height is it preferred to have 30% compression travel and 70% for droop, or 50/50, or what?
 
I'm guessing you are a mechanical engineer.....

IOW,
I have no idea what you are talking about!!:gag:
 
60/40 c/d is what I've heard desert racers use in general but wheeler probably switch it 40/60 or even more. I don't know if there is a set ratio.
 
Thanks for your inputs Weasel, 40/60 might be just right.

FYI, I run mostly trails and have fun on the rocks. I'm riding on 33's with ome leaf pacs, coils (zj), and long travel shocks. I want to keep my center of gravity low and maintain a good balance of compression and extension on my shocks. I think, with the right sized spacers on the coils, and the right shackle in the back I might be able get to the desired ratio of shock compression vs extension. I'm just curious what might be. I'm thinking 30% for compression, which would be around 3.25 inches of up travel, and 70% for droop, which would be near 8 inches of down travel. Is that too radical?

I'm wondering what others run, or if people don't concern themselves with this.....just get the lift they want and forget about it.
 
tdr1213 said:
Thanks for your inputs Weasel, 40/60 might be just right.

FYI, I run mostly trails and have fun on the rocks. I'm riding on 33's with ome leaf pacs, coils (zj), and long travel shocks. I want to keep my center of gravity low and maintain a good balance of compression and extension on my shocks. I think, with the right sized spacers on the coils, and the right shackle in the back I might be able get to the desired ratio of shock compression vs extension. I'm just curious what might be. I'm thinking 30% for compression, which would be around 3.25 inches of up travel, and 70% for droop, which would be near 8 inches of down travel. Is that too radical?

I'm wondering what others run, or if people don't concern themselves with this.....just get the lift they want and forget about it.
unless you are building from the ground up, I don't see how you have control of this, find the shock that fits and use it, that is for the stock shock mounting locations, if you were going to modify the stock shock locations you may be able to control this but you will likeley have to give up ground clearance or go through the floor/hood. I have had problems with the shocks being too long, too much droop and not enough compression. Unless I am reading this wrong, you really don't have much control over this with stock shock locations. I guess I am asking for clarification on what exactly you are trying to do.
 
Regardless of the mounting,the droop/compression(travel) is going to be "fixed" based on "your" suspension set-up(springs/shackles/bumpstops).You take your measurements and find a shock to fit the needs!
 
Skullvarian said:
find the shock that fits and use it
The whole percentage thing really through me earlier. After reading more it all kinda fell together for me.
I was under the impression that the above quote was the best way to get correct length shocks. Simply measure and get what fits. I need to get new front shocks pretty quickly and want to make sure I know what the heck I'm doing! I thought it was pretty simple, no?
 
Skullvarian said:
I have had problems with the shocks being too long, too much droop and not enough compression.

I'm interested - How much was too much droop? How little was not enough compression?

I would like to stick with my ome shocks which have 11.25 inches of travel in the front and 10 inches in the rear. I was thinking I could manipulate the static ride height, via shims, in order to take full advantage of the shock travel...specifically the droop, and droop is limited by the length of the shock. For example, I once saw a rig that was lifted high (probably too high) and the shocks only had a few inches of droop left in them - not a good set up in my mind. Maybe he just had the wrong shocks.
 
RCP Phx said:
Regardless of the mounting,the droop/compression(travel) is going to be "fixed" based on "your" suspension set-up(springs/shackles/bumpstops).You take your measurements and find a shock to fit the needs!

Yes, the shock travel is fixed. But can't we, with minor modifications (shims, extra leafs, shackels, longer or shorter coils, bar pin eliminators, relocating the shock mounts etc.) set our ride height that would allow for as much droop that logically makes sense?
 
If yoiu want more travel on a stock set up get the rancho or likewise shock for the 1.5- 2 inch lift. They will fit and will have more travel. if you think that the Xj is sagging then rearc the rear springs and put in some new front coils. Other than that if you arent doing serious mods to the chassis then just buy the right size shock for it.
 
tdr1213 said:
Yes, the shock travel is fixed. But can't we, with minor modifications (shims, extra leafs, shackels, longer or shorter coils, bar pin eliminators, relocating the shock mounts etc.) set our ride height that would allow for as much droop that logically makes sense?
You keep looking at this completely backwards.If you change your set-up w/ different springs,shims,shackles,coils,etc.,now you have a "different" "fixed" number to order your shocks by.
 
tdr1213 said:
I'm interested - How much was too much droop? How little was not enough compression?

I would like to stick with my ome shocks which have 11.25 inches of travel in the front and 10 inches in the rear. I was thinking I could manipulate the static ride height, via shims, in order to take full advantage of the shock travel...specifically the droop, and droop is limited by the length of the shock. For example, I once saw a rig that was lifted high (probably too high) and the shocks only had a few inches of droop left in them - not a good set up in my mind. Maybe he just had the wrong shocks.
too much droop is where the coil spring unseats itself and not enough compression is where the shock limits the compression before the bumpstops. I am talking about in the shock itself, as if I tried to get a longer travel shock, my compression would be reduced and the droop would be non-realistic, it is about cycling your suspension and measuring shock mount to shock mount at full compression/then full droop, then you find a shock that operates within that range allowing for reasonable compression/droop.
 
RCP Phx said:
You keep looking at this completely backwards.If you change your set-up w/ different springs,shims,shackles,coils,etc.,now you have a "different" "fixed" number to order your shocks by.

Exactly, The only way to preset a travel ratio is to move the shock mounts or form a ground up build. Even with shims or spacers all you are doing is changing the suspension height, the shock points are still the same, so the travel ratios is the same.
 
Weasel said:
Exactly, The only way to preset a travel ratio is to move the shock mounts or form a ground up build. Even with shims or spacers all you are doing is changing the suspension height, the shock points are still the same, so the travel ratios is the same.
right, but at that higher height... the shock is now extended a little bit more...i.e. a greater % of up-travel vs. down-travel.

the question should be: "how much up travel(inches) is necessary for the type of wheeling i do, and will i need any droop once i achieve that?" my jeep may have 10" of total potential travel and if i lift it... it may still only have 10" of travel (bumpstops and links limit travel), or it may then have 12" of potential travel and the shocks will limit the droop/compression.

I say, if the wheeling you do is constantly bottoming out the bumpstops(assuming they're set to hit before your shocks)... you should get a shorter shock, or move the mounting points. if you never hit the bumpstops and want more droop, like for rocks, you should get a longer shock, or move the mounts closer together and adjust the bumpstops. OR you could move the mounts and adjust the bumps and get longer shocks to increase overall travel(may be limited by susp, steering, etc.)
 
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jjvande said:
right, but at that higher height... the shock is now extended a little bit more...i.e. a greater % of up-travel vs. down-travel.


The way you explain it, the shock will top out, and limit up travel.(won't extend any further) I think some of you guys are making this alot harder than it is.
 
Haleyes said:
The way you explain it, the shock will top out, and limit up travel.(won't extend any further) I think some of you guys are making this alot harder than it is.

my axle moves downward when the shocks extend
 
jjvande said:
my axle moves downward when the shocks extend

My situation.
I have front shocks designed for a 3" lift. (exact specs are unknown to me, just know that they are for a 3" lift for an XJ. they are Rusty's) Now, the Jeep is setting at 6". The shocks are now extended further than it was when the jeep sat at 3". When the axle droops, it will limit the downtravel of the axle due to the shock being fully extended and physically unable to go out any longer.

My plans are to take the shocks off and flex the jeep to see what I need. I'll measure form mouting point to mounting point, getting a measurement for extended and compressed. I'll then go through the different shock specs and find one that will work best for me.

I think you might need to worry LESS about percentages and more about a shock that works best for you.


Hale
 
this makes sense... my case is a little different

the rear of my xj is lifted about 4-5". the shocks i have installed on it will allow the wheel to trave up about 4" before it hits the bumpstops. I designed it this way so that the leaf springs aren't bent too much and turn into "W". Now, the rear will droop another 9-10 inches or so and the 14" shocks i have will let it. now say that i dont need so much down travel, but i need to get more up travel...for hitting bumps and what not... i could throw on a 12" travel shock and now it may have 2" more up travel and 2" less down travel.


i think the answer to the original question is not easy... it depends on other factors like limitations in steering, links, springs, hoses, driveshafts, and also what type of wheeling you plan to do and are you willing to change some of these things to get the kind of travel you want. It seems as though the rock crawlers want more droop, the desert guys want more compression from static height. then again, this could also differ front to rear. on a lot of pre-runners the rear axle will have a lot of droop to keep the rear on the ground... but then you dont want to be hitting your bumps all the time either.


the battle I'm having is that i just set up the rear of my jeep with a ton of droop and now that the springs have sagged an inch or so... i dont have a lot of up-travel left and am always hitting the bumps with the type of wheeling i do.

anyway.........hastahastahastahastahastahasta
 
tdr1213 said:
Thanks for your inputs Weasel, 40/60 might be just right.

FYI, I run mostly trails and have fun on the rocks. I'm riding on 33's with ome leaf pacs, coils (zj), and long travel shocks. I want to keep my center of gravity low and maintain a good balance of compression and extension on my shocks. I think, with the right sized spacers on the coils, and the right shackle in the back I might be able get to the desired ratio of shock compression vs extension. I'm just curious what might be. I'm thinking 30% for compression, which would be around 3.25 inches of up travel, and 70% for droop, which would be near 8 inches of down travel. Is that too radical?

I'm wondering what others run, or if people don't concern themselves with this.....just get the lift they want and forget about it.
That is about my situation too. I'd like to keep CG low, but more importantly, I'd like to keep my LCA's closer to horizontal for better road ride. So I'm resisting going higher than my 3 inch lift for now. I'm running 265/75/16's on stock rims with 1.25" spacers (just cut the front fenders..) The shocks I had were specified for a 3" lift. Static ride measured 20", shock extended to 21". Not a good situation. I removed shock, measured droop, and got a shock that could handle that, in addition to further droop if I go to a 4-4.5" spring, and a body that didn't limit things too much! I'm figuring my tires are actually gonna determine my bumpstop positions (adding 2 inches this weekend). So, I've got slightly more than 2.5" uptravel, and slightly less than 8" droop. Extended measurement was something near 24"? The shocks go to 27" to give me some room to grow.
I was concerned about minimal compression, but it hasn't been an issue on the street, and I don't do anything fast off road! I believe the minimal compression, and maximal droop is the philosophy of Teraflex's LCG lifts for TJ's.
Hope that helps...the shocks are RS9000's
 
Lots of great posts and insights. Thanks guys. I'm currently at 50/50 - my rig sits right in the middle of the shock....travel wise. Really, it boils down to suspension "fine tuning". I think I will lower it an inch or so to provide for a little more extension over compression. Even though I mainly run trails, I sure like going fast from time to time and I don't want to slam the bumpstops. While we all have different needs, I think the original suggestion of 40% compression and 60% droop (if you can get there) was probably spot on for most trail rigs.
 
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