Lets talk about coil springs.

seanR · Oct 13, 2005

I am planning on a new front set up this winter.
I have the axles and I know what I am going to do for control arms.
I found a catalog that sells coil springs in any size shape and rate a guy could want.
Right now I have the R.E. 4.5 springs and a 1.5" spacer on top.
I run 33"'s

I want 35"s

What would I need for spring rate to achieve this?
Any one know about spring rate, how to figure it, what works best?

CRASH · Oct 13, 2005

I run a 250 lb/in spring and love it. THe best spring i have ever run, and I've run a lot of different springs. It is the SkyJacker 8" spring. The RE ZJ spring is about 215 lb/in. The regular RE XJ spring is about 195-200 lb/in.

Spring rate calculator.

http://www.proshocks.com/calcs/coilsprate.htm

Danno · Oct 13, 2005

Andy, I'm running the RE1341 3" ZJ coils and don't like the soft spring rate. It bottoms out way too easily. Would the Skyjacker 8"give me about the same lift as the RE 3" ZJ spring? Thanks, Danno

Beej · Oct 13, 2005

seanR said:
I am planning on a new front set up this winter.
I have the axles and I know what I am going to do for control arms.
I found a catalog that sells coil springs in any size shape and rate a guy could want.
Right now I have the R.E. 4.5 springs and a 1.5" spacer on top.
I run 33"'s

I want 35"s

What would I need for spring rate to achieve this?
Any one know about spring rate, how to figure it, what works best?

Where can one find this catalog you speak of? I'm interested...

CRASH said:
Spring rate calculator.

http://www.proshocks.com/calcs/coilsprate.htm

Thank you for that, I've been looking for one... http://www.proshocks.com/calcs/coilsprate.htm

seanR · Oct 13, 2005

I have talked about it many times here.
It is a local shop for circle track racers.
They have alot of things we use also.
I have gotten rims, tie rod ends, hiems, I am going to use them for my mid arm and high steer set up also.
If I dont buy a pre-bent cage, I will get that stuff there also.

Lefthander chasssis
Enjoy!

xjbubba · Oct 13, 2005

I'm running "RE" 4.5 ZJ springs. Before installing my Chevy350, NV4500, and associated frame reinforcements, I got about 5.5 inch lift. Now that I have the extra weight, I would like a little stiffer spring. But I'm not unhappy with the way it is, except I've lost ~1 to 1.5 inches of lift that I need to recover when I install my new D44.
Crash--what kind of lift do your 8" Skyjackers give you? Can you guess at your current vehicle weight? I'm currently at ~4150lbs.
I experimented with the Spring Rate Calculator Crash referenced in his post. I used numbers out of a book titled Chassis Engineering, by Herb Adams. He covers spring rate and gives a formula for calculating spring rate. Using the data in his example, plugged into the Spring Rate Calculator, I get 247lbs-inch; the book gives 166lbs-inch. The constants in his formula are based on normal spring steel. This is quite a difference. Any one like to comment on the difference?

Jes · Oct 13, 2005

Danno said:
Andy, I'm running the RE1341 3" ZJ coils and don't like the soft spring rate. It bottoms out way too easily. Would the Skyjacker 8"give me about the same lift as the RE 3" ZJ spring? Thanks, Danno

Danno, the 8" Skyjackers will net about the same lift as a RE 4.5" ZJ spring with a 2" spacer.
Here's a picture of them uninstalled side by side for reference...

I'm really happy with these coils.

Beej · Oct 13, 2005

seanR said:
I have talked about it many times here.
It is a local shop for circle track racers.
They have alot of things we use also.
I have gotten rims, tie rod ends, hiems, I am going to use them for my mid arm and high steer set up also.
If I dont buy a pre-bent cage, I will get that stuff there also.

Lefthander chasssis
Enjoy!

Thanks!
:wave:

Jim63 · Oct 13, 2005

hmmm so how much of a difference is the 4.5 RE ZJ coil compaired to the 4.5 XJ coil? I need to get rid of my 3" rustys coils

xjj33p3r · Oct 13, 2005

Jim63 said:
hmmm so how much of a difference is the 4.5 RE ZJ coil compaired to the 4.5 XJ coil? I need to get rid of my 3" rustys coils

You get an inch more out of the zj coil.

MaXJohnson · Oct 14, 2005

xjbubba said:
I'm running "RE" 4.5 ZJ springs. Before installing my Chevy350, NV4500, and associated frame reinforcements, I got about 5.5 inch lift. Now that I have the extra weight, I would like a little stiffer spring. But I'm not unhappy with the way it is, except I've lost ~1 to 1.5 inches of lift that I need to recover when I install my new D44.
Crash--what kind of lift do your 8" Skyjackers give you? Can you guess at your current vehicle weight? I'm currently at ~4150lbs.
I experimented with the Spring Rate Calculator Crash referenced in his post. I used numbers out of a book titled Chassis Engineering, by Herb Adams. He covers spring rate and gives a formula for calculating spring rate. Using the data in his example, plugged into the Spring Rate Calculator, I get 247lbs-inch; the book gives 166lbs-inch. The constants in his formula are based on normal spring steel. This is quite a difference. Any one like to comment on the difference?

The calculator uses coil outside diameter; Adams uses coil mean diameter(center of wire to center of wire).

mean diameter + wire diameter = outside diameter.

plug 5.62 into the calculator for spring OD and your answers will agree

xjbubba · Oct 14, 2005

Thanks for the clarification, MaxJohnson.

Gridikal · Oct 14, 2005

Maybe my RE catalog is out of date, but, wouldn't it be a lot simpler to say XJ 5.5" coils insted of ZJ 4.5" coils?

My RE catalog has them as the same part # RE1345

Jim63 said:
hmmm so how much of a difference is the 4.5 RE ZJ coil compaired to the 4.5 XJ coil? I need to get rid of my 3" rustys coils

I mean thats like saying whats the difference between 5.5" XJ coils and 4.5" XJ coils :gag:

Jim63 · Oct 14, 2005

xjj33p3r said:
You get an inch more out of the zj coil.

So how much lift will a zj re 4.5 spring give you?

turbobaja1835 · Oct 14, 2005

Jim63 said:
So how much lift will a zj re 4.5 spring give you?

Mine started out at 6" minus my 1.5" spacer and ended up at 5 1/4" after winch and bumper were finally built. I agree, they are a little soft especially after the winch bumper but they flex well.

Joe
92 XJ
RE 5.5LA
Ford 8.8 w/detroit &4.10's
Dana 30 w/arb &4.10's
4.6L stroker

Roxtar · Oct 14, 2005

I like a softer spring for off road which is why I went with the Rock Krawler 6"
They match up nicely with the rear 4 link/airshox.
However, with 180# spring rate their on-road handling is, shall we say, interesting. :laugh:

XJ_ranger · Oct 14, 2005

sean? with a technical post?

Lets talk about coil springs.

seanR

Want to puff on my pipe?

CRASH

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