Rear suspension issues?

hello, im not sure if this is the correct section on these forums to ask these questions so please forgive me. i have a 92 f150 camburg long travel i beams in front and 4-linked in rear. i am new to 4 link and to the whole prerunner scene completely so please help me. i only have 3" of droop from ride height in the rear but i have LOTS of compression (up travel?) my question is what do i need to change to make the droop and up travel where they should be because i should have more than 3" of droop. my rear spring rate is adjusted perfect and coil screw is threaded down maybe 3" from top so that's good its not stiff in rear about perfect where i have it now and my ride height is pretty decent (could be a lil higher) is it being setup like this effect performance bad? i know it could be good for jumping but i couldn't see this being good for overall performance...

rear shocks are 16" king coil overs and 16" king triple's

(also im looking for some bedsides if anyone has any)
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please let me know if you need more info or pictures
 
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TRichards

Well-Known Member
Always set up the truck with the shocks bottomed out on the up travel side with a metal to metal stop.
Most likely the upper mounts are too high.
Take your shocks off. Remove nitrogen and springs
Let the truck bottom out at full compression
Bolt in the bottom shock mount with shocks compressed. This will show you where the upper shocks need to be mounted.
You should be able to get 24" travel out of a 16" shock without too much problems. Be aware of driveline angles.
 
Thank you soo much ill do this over the weekend and get Measurements. Making new upper shock mounts shouldnt be difficult either with the way the previous owner made it, should be easy to make me some nice sheet metal mounts instead of the little tabs thats on it now.
 

RanchoPacific Motorsports

Well-Known Member
Normally the bypass shock is 18" stroke for a 16" coilover, you are not using the full stroke of the coilover, but i agree with Trichards moving the upper mounts will help.
 
I havent measured the stroke of the shocks i was just going off what i was told they were i should be getting 18 if thats what 16's get as i still havent got limit straps on it yet, i know thats bad for the shocks... just been taking it easy till i get some
 

Chris Tobin

Well-Known Member
Where are you running the truck in NC? I live in Eastern TN and would like to know. I haven't linked my truck yet, but it is coming soon...
 

Chris Tobin

Well-Known Member
I don't know either of those locations, but I mud bog raced my truck once, and I won't be doing it again!!! I am still cleaning mud off it and finding it everywhere despite hours of pressure washing!!!
 
TRichards i thought about what you said and was looking at it... if i lowered my upper shock mounts that would do nothing but change my ride height my coils and triples would still be at nearly full extension sitting on the ground... do i just need to add more weight in the rear somehow? the caging is really simple and really light, there isint much in the rear...

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TRichards

Well-Known Member
Well your rear cage structure is a little unusual.I would still take the springs off and cycle the truck so you can see what you dont like about the ride attitude thru the travel stroke. Also take your truck to a weigh station to get the overall weight of the truck. What are the weight markings on the springs?
 

TRichards

Well-Known Member
So your straight linear rate is 161.5 lbs per inch if the shock was mounted directly on the axle your motion ratio is approx 1.5 to 1 so your rate is 108 lbs per inch,
Cycle the rear axle with the springs off and measure to total wheel travel. Assuming 24" total wheel travel I would normally set it at 14" up and 10" down at ride height. Don't know if that's possible with your cage set up.
 
Guess what i did today?? So what rate springs do i need, assuming i need softer springs ill throw them on and lower top shock mounts to keep my ride height.

And yes i know the front to rear weight distribution is horrible im gonna fix that somehow

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TRichards

Well-Known Member
Springs are irrelevant at this point. What you are needing to get is wheel movement. Take the springs andoff and measure total bump and droop to get wheel movement. Take the fenders off to get pics.
 

Jacob7672

Nimrod de Ashcraft
yes, TRichards is right. You'll have to have the truck at full bump with the ground clearance you want (usually 3-4" at bump). Then you will have to build new upper shock mounts, Then respring the coil-over lighter. 300 over 350 is pretty light already so Im pretty sure he put coils that are too long on the shock, you'll probably need a shorter top spring to make it work. The other reason the springs are holding the truck up is that your aspect ratio is about 1.5 to 1 where normally its around 2 to 1 on a truck like this. That will limit your travel. The shock angles are also way off. You want them 90 deg off the lower link at full bump wich means you'll have to move the new upper shock mounts back also. To be honest your really going to want/have to build a whole new rear cage. Your missing a number of important tubes and there isn't a place for the axle to bottom out on.
 
Thank you for the help jacob i contacted king today and they suggested 16”x150/18”x250 in the rear. I think i will try that and lower top shock mounts to keep my ride height and see what happens. As for the rear design, well... im not going to blame the guy that "put it together" id blame it on the guy that designed it for the fabricator, he didnt want to do anything with this truck but jump it 15ft in the air so all he wanted was up travel and nothing in the way to restrict up travel... and yes i have thought about chopping it off at cab and redoing it multiple times but dont have the funds. Everything else looks great the interior cage looks very good front end is all camburg so it will work good soon as i get the correct springs for it...
 

Jacob7672

Nimrod de Ashcraft
Thank you for the help jacob i contacted king today and they suggested 16”x150/18”x250 in the rear. I think i will try that and lower top shock mounts to keep my ride height and see what happens. As for the rear design, well... im not going to blame the guy that "put it together" id blame it on the guy that designed it for the fabricator, he didnt want to do anything with this truck but jump it 15ft in the air so all he wanted was up travel and nothing in the way to restrict up travel... and yes i have thought about chopping it off at cab and redoing it multiple times but dont have the funds. Everything else looks great the interior cage looks very good front end is all camburg so it will work good soon as i get the correct springs for it...
Nice, well give that a try and I think it should be better. I understand what your saying. There are a lot of growing pains in this sport but this truck will provide you with a fun platform and some learning too. Go get some with it!


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