What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Hard top weight 87 K5

Chevk587

Chevk587

Whiskey bent & Hell bound
 Premium
GMOTM Winner
Joined
Feb 8, 2015
Posts
1,068
Reaction score
1,032
Location
California
Trying to dial in my coil springs and my dumb self just realized I still have my top on . When I wheel it’s normally off trying to figure out the weight of thing so I can simulate having my equipment ppl and gear to decide if I need to go with stiffer springs or not . I’ve done a search and got a varying results from 180lbs to 300lbs that’s a big difference. Any help would be appreciated.
 
So my coils are 150 over 250 with a rate of 94 the top pretty much simulates the gas tank being full I put about 400lbs in the back of my truck it dropped about 1-3/4 which I think is pretty good should I run say a 200 spring on top ? Would that benefit me or hurt me ?
 
You really need to know the unsprung weight over the axle. When I pull my tools out, the back lifts 2 inches. I am running 250/350. But the Jimmy also weighs 7000 pounds with me in it. Balanced 100 pounds front to back.
 
What is your preload at?

Also, don't forget you can calculate the 'Sprung' weight since it is sitting on springs. 1 to 1.5" inches of preload is where I believe the sweet spot is with an actual truck.

I keep editing, just to cover bases. What is your CO length and what are your spring lengths as well?

This all factors in, as well as a few more things. But to start that info would be helpful.
 
Last edited:
My preload is 2” it’s a 16” king with a 16” 150 and a 16” 250
 
You can run the dual 16", but a 16" over 18" length is much much better.

I try and keep the individual rates no more than 100lb difference, which is fine with what you have. Dual rate slider transition.

What I would do is use the current springs you have to get your sprung corner weights at ride height. For this measurement load up the truck to what would be your setup for the hardest trail you will run in the truck and 3/4 tank of fuel. My thought here is that when you run this trail, passengers will have exited the vehicle for the obstacles and the truck will be operating close to what you used to calc your numbers. You are obtaining your ideal rates here. Everything after this is the compromise we all end up dealing with.
Once you have those numbers you can then calculate which springs will get you to your goal.

Don't forget you need all the stuff not just in the bed, but also in the cab etc...

IMO, and this is debatable, If it still has a bed and does some truck duty and camping duty, with multiple people etc, I'd be shooting for 1 to 1.5" preload. I'd only go to 2" if it does not get loaded down much. The coilover geometry and link setup can play into this preload number alot, and you may find down the road you need to tune a bit.

So, you're spring rates, with the correct length of springs, and your preload all need to be calculated based off your current calculated corner weights from the existing springs you have. Create a simple spreadsheet set of equations you can use to fill in numbers and see what spring rates you need.
 
So it looks like my springs compress 10” under ride load at a combined spring rate of 95 . So 10x95 =950lbs
I believe .
So from what I’m reading I only want about 8” of compression. So @ 8” 950lbs / 8 = 118 spring rate sound correct ?
 
Chevk587 said:
@Tnsejed thats without tools and gear.
Click to expand...


You need to load the truck with tools and gear that you would normally take. Don't forget driver weight. Like I said I like to do this with the truck setup for the hardest trail I'll run.

Throw all the gear in the back where you'd put it normally. From my experience 950 on the rear ready to go in our trucks is pretty light (depending on mounted CO angle of course). But I don't know what you've done to it.

The other consideration is the gas charge. It does make a bit of a difference as the air spring effect is there in the coilover. But its minimal. Just depends how accurate you want to be (not a smartass remark, just a cover yourself on the interwebs thing).

Usually I work from shock shaft at ride height desired. You know the amount of shock shaft showing that you need for desired uptravel. You know the preload you want to run. You also know the spring lengths needed for the coilover. You know you don't want to exceed 100 lb/in between main and tender.

The one variable here that's not really a concern as long as the CO's are not at very crazy angles or mounts because you weighed with springs already at that angle, is the effective angle of the coilover. And we are assuming these are CO's mounted to the axle, not a trailing arm. That's another discussion and probably better explained by the dezert guys. As long as nothing is crazy the below will get you close and you can play with what mains and tenders are available.

So:
Shaft exposed= 16-((CW/((TS*MS)/(TS+MS)))-X)

TS=Tender Spring
MS=Main Spring
X=Preload in inches
CW=Corner Weight (sprung only)


My .015 cents. I have also already had a drink.
 
Tnsejed said:
You need to load the truck with tools and gear that you would normally take. Don't forget driver weight. Like I said I like to do this with the truck setup for the hardest trail I'll run.

Throw all the gear in the back where you'd put it normally. From my experience 950 on the rear ready to go in our trucks is pretty light (depending on mounted CO angle of course). But I don't know what you've done to it.

The other consideration is the gas charge. It does make a bit of a difference as the air spring effect is there in the coilover. But its minimal. Just depends how accurate you want to be (not a smartass remark, just a cover yourself on the interwebs thing).

Usually I work from shock shaft at ride height desired. You know the amount of shock shaft showing that you need for desired uptravel. You know the preload you want to run. You also know the spring lengths needed for the coilover. You know you don't want to exceed 100 lb/in between main and tender.

The one variable here that's not really a concern as long as the CO's are not at very crazy angles or mounts because you weighed with springs already at that angle, is the effective angle of the coilover. And we are assuming these are CO's mounted to the axle, not a trailing arm. That's another discussion and probably better explained by the dezert guys. As long as nothing is crazy the below will get you close and you can play with what mains and tenders are available.

So:
Shaft exposed= 16-((CW/((TS*MS)/(TS+MS)))-X)

TS=Tender Spring
MS=Main Spring
X=Preload in inches
CW=Corner Weight (sprung only)


My .015 cents. I have also already had a drink.
Click to expand...
I have a build thread you can kinda see what I’m working with “here I go “ is the name .
 
For what it's worth... There is nothing wrong with adding 3" of preload if the spring is too light..
 
You must log in or register to reply here.

Latest Posts

Top Bottom