TTB coil-over spring rates/lengths

[Rmc]

I thought of something else, coil bind dosnt apply to ride height springs due to them being fully compressed 90 percent of the time, most are flat coils instead of round but it depends on brand and rate choice.

[cs_drums]

Yeah I may go that route. Anyone interested in trading 14" 350lb for 12" 350lb coils?

[Kel Fab Creations]

Don't you think you should go stiffer on both? From what I've seen all the bronco guys are running 500-550 lower and 450-500 upper. I have a pair of 450-16 and 350-12 that worked good on a fully built 4.0 ranger that I'll probably sell cause I think they're too light for my bronco...

[hobbyturnedobsession]

I run 400/500 and it works well

[tcm glx]

Keep in mind, what Coil rates you run can depend a lot on stock width VS extended as well as shock placement(both upper and lower) and valving of course.

As a example, my brother runs a 500/500 with Keifers coil buckets and he has less body roll Than I do on Keifers older engine cage coil over mount on mine. I'm running 450/550 on the older cage, and the engine buckets that he sells now set the shock up at a slighter different angle, which I am sure causes a difference in performance.

[Rmc]

450 over 500 here.. But I have to quote a guy named randy Andersen ( walker Evans crew chief) right about now. " springs are to hold the truck up, all else is made up in proper valving" for what it's worth I agree to a point but I'm a lazy ass who dosnt like rebuilding his shock 20 times a day till I get it right. So ill trade coils out, just before I don't like the body roll and do the rest in valving. I'm shure all u guys have opinions on proper coil choice including weighing the sprung vs unsprung weight Method, But as I said I'm lazy but u do need a certain stiffness especially if u plan on the rough stuff. Someone needs to get some longacher scales so we can all borrow them.

[cs_drums]

450 over 500 here.. But I have to quote a guy named randy Andersen ( walker Evans crew chief) right about now. " springs are to hold the truck up, all else is made up in proper valving" for what it's worth I agree to a point but I'm a lazy ass who dosnt like rebuilding his shock 20 times a day till I get it right. So ill trade coils out, just before I don't like the body roll and do the rest in valving. I'm shure all u guys have opinions on proper coil choice including weighing the sprung vs unsprung weight Method, But as I said I'm lazy but u do need a certain stiffness especially if u plan on the rough stuff. Someone needs to get some longacher scales so we can all borrow them.

This is a arguement I have heard several times and it make the most sence to me. Wouldn't stiffer rate also get me in the opposite direction of what I am shutting for now, 1-2" lower?

Don't you think you should go stiffer on both? From what I've seen all the bronco guys are running 500-550 lower and 450-500 upper. I have a pair of 450-16 and 350-12 that worked good on a fully built 4.0 ranger that I'll probably sell cause I think they're too light for my bronco...

Did you already get new springs. What are you looking to get for the 350-12s?

[Rmc]

Yes, but u can go triple rate and have the ride height u want and the proper rate for the weight, I'm far from any kind of expert on this topic. But I do have friends running 12/14 on a 14 inch coilover. I think I'm running a 16 and a 12 for the same result, it's all about how u get where u want to be but maintain low roll and full cycle.

[Kel Fab Creations]

Did you already get new springs. What are you looking to get for the 350-12s?

I haven't bought new springs yet. To be honest, my mind isn't totally made up as to if I wanna get new ones or try these out. I'd have to get at least 125 for the set IF I decided to get rid of them.

[Rmc]

Yes, but u can go triple rate and have the ride height u want and the proper rate for the weight, I'm far from any kind of expert on this topic. But I do have friends running 12/14 on a 14 inch coilover. I think I'm running a 16 and a 12 for the same result, it's all about how u get where u want to be but maintain low roll and full cycle.

I can't remember my coil lengths I do remember there 2 different lengths, I can measure them if u want. I have a tired looking pair of 600 lb springs for a 2.5 if anyone is interested. There sun faded red, 14 inch I think but, cheap and good enough to run or testing.

[outlaws4x4]

Hey guys, was hoping you could help me out with my spring rate calculations. My 3 year build is finally at the end and one of the last things to do is order the coils. I put it in a calculator but they are not making much sense to me. for some reason im getting huge spring rates for the rear. I know there is a leverage effect from the 4-link arms but im gettings rates of 1700lbs and i thought they only make spring rates up to about 800lbs.

please help if you can thanks.

So heres what i have.

Its pretty heavy total weight with fuel,driver and Navi is 5300lbs.

16x2.5" coil overs on all 4 corners.
2" hydro bumps on all 4 corners.
quad bypass 16x3.0 on front
qaud bypass 18x3.0 on the rear.

The front is a TTB beam 4wd front end with 18" of travel
The rear is a 4-link with 28" of travel


Corner weights:sprung:
FL=1238lbs FR=1221lbs
RL=1186lbs RR=1243Lbs

Corner weights: Un-sprung:
FL=253lbs FR=225lbs
RL=388lbs RR=348lbs


Front:FR
Wt=18"
d1=30"
d2=43"
angle theta=0
angle alpha = 7.5 degrees
Droop %=50%

Front:FL
Wt=18"
d1=29.5"
d2=42.5"
angle theta=0
angle alpha = 6 degrees
Droop %=50%

Rear:RL
Wt=28"
d1=17"
d2=47.75"
angle theta=0
angle alpha = 1 degrees
Droop %=49.4%

Rear:RR
Wt=28"
d1=17"
d2=47.75"
angle theta=0
angle alpha = 1 degrees
Droop %=49.4%

I dont know what the (SUR)"Step up rate" should be. I have never played with coil overs before. I want to run a duel rate.
What do people recomend?

Thanks

oh and heres a couple of pic's of it.

[outlaws4x4]

FYI the i got the info from http://www.swayaway.com/calculators/swa ... .php#step8
for what D1 and D2 ect are.

[PaulW]

Search. Lots of info here
Your coil/shock info apparently is for a trail rig. Is that what you want?
For Baja bigger is best.
PW

[outlaws4x4]

What do you mean Paul? are you saying a 2.5"x16 coil-over plus a 2.0 hydrolic bump stop plus a 3.0x16 quad bypass shock Per corner is trail spec????
Its not meant to be. Its a Class 8 off road race truck here in Australia. very hard to find good info. Im not looking for a trail spec iv built this truck to race.

cheers

[Rmc]

Try this calculator, you calc the rate then calc the duel rate numbers. I input your numbers but they seemed a bit heavy to me. Verify the spring to pivot distance ect. There's a how to use the calculator page on the second section.

http://www.f-o-a.com/calculator.html

[philofab]

You are going to want to be in the neighborhood of 400/550 on each corner. The calculators are good for a starting point but driving style and terrain also make a big impact on what is actually needed.

Do you have a local source of coils or are you stuck paying big $$$ in shipping and tariffs?

[outlaws4x4]

Im stuck pay the shipping im most concerned about my rear spring rate as i think i have stuffed up when making the arms.
Im getting a main spring rate of 1753 and a tender of 1168......... not good i think im going to have to re-make the shock mounts and the trailing arms so i can move the shock further along the trailing arm to lessen the leverage.

What about spring length do you run a 16"/10"?????

[outlaws4x4]

you can see here where the shock mounts are on the arms

[PaulW]

What do you mean Paul? are you saying a 2.5"x16 coil-over plus a 2.0 hydrolic bump stop plus a 3.0x16 quad bypass shock Per corner is trail spec????
Its not meant to be. Its a Class 8 off road race truck here in Australia. very hard to find good info. Im not looking for a trail spec iv built this truck to race.

cheers

====
Now its all merged so you can evaluate what all the guys said
PW

[philofab]

Your rear links are short at 47", and your shock should be towards the rear axle. The numbers you have are either measured wrong or you are not using all of the shock travel.

Most links on race trucks here are 56-64" long with the shock working at a 2/3 reduction.