Rear Spring Options For Lifting Your WD21 Pathy

[Harbinger]

Jeep Grand Cherokee

[Guest rolling]

oo ok whew that helps ALLOT!! i know what those are! I WANT ONE WITH THE qUADRA-DRIVE anyway that liek way down the road

i want to see what my pathfinder can do with 5sp and 220k!

[k9sar]

Do not use standard Cherokee 6-cyl front springs, they will not give you any lift.

 

this has gotten confusing. there are so many variations in springs...

 

According to Aarons site, the springs I want for my pathy are:

 

Jeep Grand Cherokee V8 springs:

Outer diameter: 5.25"

Inner diameter: 4"(after trimming)

Coil thickness: .52"

Coil height(uncompressed): 17"

 

I think the coil thickness listed is in error. Other discussions list them as .56". The stock springs for an I6 are the FJ springs that spec at .52" (which I bought a pair based on the above info). There was a variation on the I6 JGCs that used a FN spring which measured .56" I got 1 of those cause that's all that was there.

 

I'm now believeing that the .52 springs will not provide any lift and I need another .56 (or a pair of GN's at .60").

 

sigh.

 

anyone need a pair of FJ springs?

[88pathoffroad]

There are two types of springs used in the JGC's apparently. On the Laredos with the Upland suspension package(maybe) they got 9-coil .56" coils. The stock JGC's got 9-coil .52" coils AFAIK. I've measured many a set and only found two sets of the .56" coils, both off Laredos.

 

And once again, the standard 8-coil Cherokee coils won't give you any lift AFAIK. It's been tried...

[k9sar]

so, for clarification, the "FJ" springs are .52 and are basically the same as are on the stock pathy. The "FN" springs off the heavy duty suspension are .56 and should provide lift. I am learning more and more about jeep springs and there is apparently a true up-country spring that measures close to .6. The code is GN I think. I'll edit this post tomorrow when I get to my office and find my notes.

[88pathoffroad]

Not really, no. Let's not refer to them with OEM part sticker letters, things are getting confusing. Let's refer to the vehicle they specifically came off of.

 

The .52 springs from a Grand Cherokee will still give you about 3" of lift. The .56" coils from a Grand Cherokee will definitely give you 3" of lift. What you don't want are Cherokee springs, they're .50" with 8 coils.

 

Apparently that's what you got instead of the Grand Cherokee springs, from what I could see.

[k9sar]

The ones I have are 8-coil .52" 17" length off ... well... I'm not sure. Definately not off a JGC but maybe an 80's cherokee w/ I6. The third spring I have is a 9-coil .56" 17" off a JGC Laredo w/ I6.

 

As the pathy springs are 8 coil .50" 16.5", I'm guessing that the 8x.52x17's may give a little lift but what I really want are the 9x.56x17's which I unfortunately only have 1 of.

 

Since I have a 4-door w/ tire carrier, I doubt I'd get much of a lift with the 8x.52x17's.

 

Of course... two days ago it was in the high 70's and sunny. Now it's in the 30's with 40mph winds and flurries. I believe the springs will stay put for now.

[mws]

Throwing another handful of mud into the soup... and then hopefully some clarifying medium....

 

I have a pair of front springs out of a 4.0L (I6) Jeep something sitting in front of me (thanks, Red!).

They have just under 8.5 coils, but it appears Red already cut the pig tail off.

The springs are just over 17" long.

The wire is .54 to .55 inches in diameter

OD of spring is about 5.25", ID is about 4.00"

 

I will be installing these in a month or two and will report what lift (if any) they provide.

 

In a previous life, I worked for NUMMI where we produced Toyota Corollas and Geo Prizms (same car, different cosmetics). There were at least 10 different models of front springs used for this "1" car depending on options and trim levels. DX, LE, GXI, LXI, with A/C, without A/C, etc. And that was just for the model year in production - there were some year to year changes as well. Only 2 versions of rear spring as I recall.

 

So it is very likely (and looking pretty sure) Jeep used more than two different front springs over the years. They were probably not as anal about providing "optimal" suspension as Toyota was, but as our data base builds here, it appears they did offer some variations.

And the aftermarket companies will not want the hassle of stocking all these varieties, so they are going to offer only a "universal" or "one size fits all" variant.

 

So my suggestion is that we're going to have to start measuring and reporting more information to provide more accurate predictions of results. The wire diameter, number of coils, and static length (without pigtail) will all affect the amount of lift that will result. And heres how each will affect:

 

Wire diameter: Directly affects spring rate, or how much the spring will compress under a given load. Spring rate changes as the square of the change in diameter (eg, doubling diameter quadruples spring rate). The larger the diameter, the stiffer it will be. All other things being equal, the larger diameter wire will provide more static lift as it will compress less under the weight of the vehicle. It will also provide a stiffer ride as it will compress less under the dynamic load induced by a bump.

EDIT: DOHHH! The spring rate increases much more than that - it increases at the rate of diameter change to the 4th power!. So doubling the diameter gives 16x the spring rate! Going from .52" to .56" gives, umm, something like 35% increase in spring rate. That's a bunch.

 

Number of coils: Directly affects spring rate as a linear function. The more coils, the lower the spring rate. This only applies to coils that are NOT in contact with each other.

 

Static length: Obviously, a longer spring will provide more lift. ASSUMING the wire diameter and number of coils is EXACTLY the same. Most folks are surprised to discover this is probably the LEAST important factor. A very long spring with lots of coils of smaller diameter wire will compress a lot under the static load of the weight of the car, and will end up lowering it. A shorter spring with thicker wire and fewer coils will lift it.

 

Edited March 15, 2006 by mws

[88pathoffroad]

To date I've pulled at least 10 pairs of JGC springs. 8 pairs were 9 coils, .52" thickness. 2 pairs were 9 coils, .56" thickness. I measured them all to make sure before selling them.

[k9sar]

well.. that's why I was trying to get the specs for OEM letter coded coils. There are LOTS of different coils that Jeep uses. Stock springs are lettered from FC to FP. Then there are the up-country option springs which begin with G rather than F. Lots of variations. In my junkyard, however, they are mainly non-grand cherokees with I6 and nearly all use the FJ spring which is 8 coil 17" long .52wd. ALL FJ springs measured the same. Not ALL of the same vehicles had the same springs in them. Found 2 '93's (10th digit of VIN tells the year) that looked identical but had different springs. I also foung .56we 8 coil springs that were about 15.5" long (busted my knuckles pulling one then discovered it was actually shorter). Oh well.

 

Bottom line...I need a .56wd 9 coil 17" friggin spring for my lift to match the one I already pulled and my JY doesn't have anymore.

[thatguy03]

ok this is gonna sound like a dumb question but here goes anyways

when counting the coils is there a specific way do u start where it starts and go up in a straight line counting each one also do u include the small coil at the top

[thatguy03]

:help: ok here's my situation right now bought a pair of coils from a jgc v8 told the guy at the counter they had to be from the front (got them last week) and was re reading the forumn where it was talkin about the sizes and mesurments as in lenght 17 inches so i went and measured the ones i picked up and it only came to like 14... ohoh.... anyways i took em back todayand said they werent long enough and i told the guy 17 " so he went to the back and came out with another pair looks like same thickness and the full lenght is 18" took a tape measure to see the thickness of the spring in the middle it looks like 1/2 an inch maybe just a smidge more and it has what looks like 8 and a bit of coilsthe bit being the rest of the coil where its tapered in.....

so my question after that long winded info bit is how do i determine weather or not they will work short of cutting them and installing them they have been marked 98 cher in yellow jy paint would like to figure this out before cutting incase i have to get other ones thanks all

[88pathoffroad]

Count the coils by starting at one end, circling around until you reach the point where the coil makes a complete circle, then count up from there. It sounds like you have the right springs to me.

[thatguy03]

do you include the smaller coil as one too?

[Mr. Pickles]

Mmmmm... coils. (96 JGC front)

[88pathoffroad]

do you include the smaller coil as one too?

In stock form, yes. If you've cut it off, no.

[thatguy03]

here is a pic of them hope this works (first time posting pic)

 

http://i62.photobucket.com/albums/h120/pathvoyuer/coils2.jpg[/img][/img]

[k9sar]

Throwing another handful of mud into the soup... and then hopefully some clarifying medium....

 

I have a pair of front springs out of a 4.0L (I6) Jeep something sitting in front of me (thanks, Red!).

They have just under 8.5 coils, but it appears Red already cut the pig tail off.

The springs are just over 17" long.

The wire is .54 to .55 inches in diameter

OD of spring is about 5.25", ID is about 4.00"

 

I will be installing these in a month or two and will report what lift (if any) they provide.

 

In a previous life, I worked for NUMMI where we produced Toyota Corollas and Geo Prizms (same car, different cosmetics). There were at least 10 different models of front springs used for this "1" car depending on options and trim levels. DX, LE, GXI, LXI, with A/C, without A/C, etc. And that was just for the model year in production - there were some year to year changes as well. Only 2 versions of rear spring as I recall.

 

So it is very likely (and looking pretty sure) Jeep used more than two different front springs over the years. They were probably not as anal about providing "optimal" suspension as Toyota was, but as our data base builds here, it appears they did offer some variations.

And the aftermarket companies will not want the hassle of stocking all these varieties, so they are going to offer only a "universal" or "one size fits all" variant.

 

So my suggestion is that we're going to have to start measuring and reporting more information to provide more accurate predictions of results. The wire diameter, number of coils, and static length (without pigtail) will all affect the amount of lift that will result. And heres how each will affect:

 

Wire diameter: Directly affects spring rate, or how much the spring will compress under a given load. Spring rate changes as the square of the change in diameter (eg, doubling diameter quadruples spring rate). The larger the diameter, the stiffer it will be. All other things being equal, the larger diameter wire will provide more static lift as it will compress less under the weight of the vehicle. It will also provide a stiffer ride as it will compress less under the dynamic load induced by a bump.

EDIT: DOHHH! The spring rate increases much more than that - it increases at the rate of diameter change to the 4th power!. So doubling the diameter gives 16x the spring rate! Going from .52" to .56" gives, umm, something like 35% increase in spring rate. That's a bunch.

 

Number of coils: Directly affects spring rate as a linear function. The more coils, the lower the spring rate. This only applies to coils that are NOT in contact with each other.

 

Static length: Obviously, a longer spring will provide more lift. ASSUMING the wire diameter and number of coils is EXACTLY the same. Most folks are surprised to discover this is probably the LEAST important factor. A very long spring with lots of coils of smaller diameter wire will compress a lot under the static load of the weight of the car, and will end up lowering it. A shorter spring with thicker wire and fewer coils will lift it.

 

hey mws... did ya lift your truck yet?

 

I just found a pair of .55 springs (FM's) and was wondering if I should get them. How much lift did you get (if you did it yet)?

[k9sar]

More information than anyone cares....

 

Jeep offers two basic suspension options on the Grand Cherokee ZJ

models, a standard base suspension and an optional UpCountry

suspension designed to improve performance in off-road driving.

 

Chrysler makes a variety of springs for the GC. There are two main

types, base and HD (heavy duty), and in each type category there are 5-10

different springs with different GVWR (Gross Vehicle Weight Rating)

capabilities. The springs are denoted by a two digit code as well as

a part number.

 

Higher GVWR springs from either the base or HD spring tables in the

factory parts catalog are stiffer and also raise the vehicle

slightly. The UpCountry (off-road) suspension option for the GC

includes higher GVWR springs.

 

In addition to whether the ZJ is equipped with standard or UpCountry

(option code AWE) suspension as well as what other weight affecting

options came from the factory different springs are selected. For

example if the jeep has the trailer hitch or skid plate/tow hook package,

there would be stiffer springs in the rear to compensate for the weight

of these items.

 

The thicker diameter wire indicates an increase in rate. The rate of

a spring is proportional to the 4th power of the diameter, so even

small differences in diameter make a substantial difference in rate.

The UpCountry V8 "GN" code front springs (.600) are 32% stiffer

than the stock "FN" code V8 springs (.560)

 

Though I do not have the full specs for the springs available, I have

determined through visiting multiple salvage yards that the most

common JGC spring (and normal cherokee for that matter) out there

are the FJ (.520) springs which, I believe, may give a 4-door pathy

with a wheel carrier about 1/2" of lift since the stock springs are only

.500 but differ in coil count etc.

 

I was amazed at the quality of the tags remaining on the springs.

The following part numbers, codes and wire diameters are known:

(so far)

part num code dia tag color

52001117 FH - .500 (grey)

52088102 FJ - .520 (green)

52088103 FK - .530 (yellowish. old part number 52001119)

52088181 FL - .540

52088361 FM - .550 (blue)

52088362 FN - .560 (yellow) [definately yellow, just got a pair]

52088104 GK

52088105 GL

52088363 GN - .600

52089141 GP

52089171 DL

 

I'll edit as I gather more info.

Edited May 1, 2006 by k9sar

[88pathoffroad]

Hey, you learn something new every day. Thanks a ton for the info, k9sar.

[k9sar]

all this cause I'm trying to find a mate for the spring I pulled from a jeep-scarce jy.

[RedPath88]

52088362 FN - .560 (white)

The "White" that you mention, is that the color of the tag?

Because those are the ones that I have, except that the tag is not white it is yellow with black text on mine.

[k9sar]

The "White" that you mention, is that the color of the tag?

Because those are the ones that I have, except that the tag is not white it is yellow with black text on mine.

could be yellow... it's not blue or green, looks white. I'll update the post. Thanks

 

I also think the FL are a light tan but I don't recall clearly. I was in a hurry and they were thinner than I wanted.

[RedPath88]

Ok I just wanted to make sure..

I was thinking that "maybe" the color of the tag was random or may have changed at some point.. worst case was that maybe the color ID'ed them is some way as well. But I really did not think that to be the case.

[k9sar]

teh only reason I am trying to include the color is because they seem to differ between codes and sometimes the letters are too hard to read (forget about the part numbers, sheesh!)