egghead Posted May 29, 2015 Share Posted May 29, 2015 Hey guys so I picked up a 90' MJ the other day. It's currently 2wd with a 3" lift up front and 0 lift in the rear. I'm looking to get ideas on a SOA rear without netting 5" I'm swapping out the 35 rear for an 8.25 with 4.10s. (Yes I'm converting to 4wd as well) picked up an AX15, 231 and a set of 4.10 axles for 350$ If I make spring perches as low as possible, (machinist by trade) use XJ shackles and possibly take out a spring.. I'm thinking I may be close to where I want to be. Am I crazy? What am I missing? I'll throw another curve ball and note I'm looking to gain load capacity too.. hmm Egg -I think I'm thinking too much- head Link to comment Share on other sites More sharing options...
Eagle Posted May 29, 2015 Share Posted May 29, 2015 Hey guys so I picked up a 90' MJ the other day. It's currently 2wd with a 3" lift up front and 0 lift in the rear. I'm looking to get ideas on a SOA rear without netting 5" ... I'll throw another curve ball and note I'm looking to gain load capacity too.. hmm Not possible. Link to comment Share on other sites More sharing options...
Pete M Posted May 29, 2015 Share Posted May 29, 2015 2 things to keep in mind: -the packs have to be stiff enough to resist spring-wrap -the shackle needs to be long enough or the leafs will bind upon full stuff. why are you wanting to go SOA and not stick with new metric ton leafs and SUA? Link to comment Share on other sites More sharing options...
egghead Posted May 29, 2015 Author Share Posted May 29, 2015 Just exploring my options, I figured I'm going to be cutting off perches of the 8.25 already anyway. I do have access to a set of XJ packs to build a "Bastard pack" and have a set of chevy drop shackles. I'm unclear on where to pick up a set of metric ton packs? Link to comment Share on other sites More sharing options...
mvusse Posted May 29, 2015 Share Posted May 29, 2015 It might be doable by only keeping the MJ main leaf, and bastard packing the xj pack in there. You're just going to have to try and see. Link to comment Share on other sites More sharing options...
Jeep Driver Posted May 29, 2015 Share Posted May 29, 2015 I can tell you what works- Standard GS leafs will give you 3", JKS shackles will give you 1"........reality is I'm at 3.75" over where I was 6 months ago. Depending on which direction you mount the JKS shackles........0-1" lift, I just swapped the direction on mine a couple of nights ago and gained the 1". OME coils up front will gain you nearly 2" (+additional isolator= 3") . I just installed the JKS ACOS system and adjusted it for 1" more, now at 4" and level with rear. I have had exactly 1100lbs in the back of mine (transfered marble from tractor trailer to job, known shipping weight) with virtually no sag.....the GS springs can handle weight. Link to comment Share on other sites More sharing options...
mjeff87 Posted May 29, 2015 Share Posted May 29, 2015 2WD rear spring packs will net @ 1" less lift on an SOA compared to a stock 4WD pack, but you're still gonna be over 3". XJ shackles would help keep you lower, but may invert. Jeff Link to comment Share on other sites More sharing options...
egghead Posted May 29, 2015 Author Share Posted May 29, 2015 I can tell you what works- Standard GS leafs will give you 3", JKS shackles will give you 1"........reality is I'm at 3.75" over where I was 6 months ago. Depending on which direction you mount the JKS shackles........0-1" lift, I just swapped the direction on mine a couple of nights ago and gained the 1". OME coils up front will gain you nearly 2" (+additional isolator= 3") . I just installed the JKS ACOS system and adjusted it for 1" more, now at 4" and level with rear. I have had exactly 1100lbs in the back of mine (transfered marble from tractor trailer to job, known shipping weight) with virtually no sag.....the GS springs can handle weight. You are talking SUA correct? What are "GS" springs? Link to comment Share on other sites More sharing options...
Megadan Posted May 29, 2015 Share Posted May 29, 2015 GS = General Springs. I replaced my rear leaf springs with GS standard leaf springs because my stock ones had broken leaves. Over a year later, and with some heavy stuff for more than half the time, they settled. After they settled, with the stock shackles, the rear sits over 2 inches higher than the front. They definitely sit higher than stock Comanche springs. Link to comment Share on other sites More sharing options...
Pete M Posted May 29, 2015 Share Posted May 29, 2015 HellCreek also makes leafpacks for MJs. regular, lift, and metric ton. should be a link in the vendors forum in the classifieds. Link to comment Share on other sites More sharing options...
WiscoXJ Posted May 29, 2015 Share Posted May 29, 2015 ive tried to figure on this as well. doesn't seem possible. thought of using the main leafs and the rest of an xj leaf pack but I bet itll still be pretty high Link to comment Share on other sites More sharing options...
Megadan Posted May 29, 2015 Share Posted May 29, 2015 I would just rock some 3" Hell Creek lift leaf springs, or maybe the military wrap MT springs from GS, and call it a day. Link to comment Share on other sites More sharing options...
Eagle Posted May 29, 2015 Share Posted May 29, 2015 2WD rear spring packs will net @ 1" less lift on an SOA compared to a stock 4WD pack, but you're still gonna be over 3". XJ shackles would help keep you lower, but may invert. To be technical, a SOA will lift any MJ, 2WD or 4WD, about 5-1/2 inches. If a 2WD starts out 1" lower than a neighboring 4WD, after both undergo a SOA they will both be lifted by 5-1/2" (+/-) and the 2WD will still be 1" lower than the 4WD. The amount of lift from a SOA is the sum of 1x perch offset ~ 1/2" 1x axle tube diameter ~ 2-3/4" 1x perch offset ~ 1/2" 1x leaf pack thickness ~ 1-1/4" Add that up and you get 5 inches as a minimum lift. Link to comment Share on other sites More sharing options...
dscowell Posted May 30, 2015 Share Posted May 30, 2015 People have taken a waggy pack and replaced the main leaf with the MJ main and got around 4". If you want 3" in the rear just stay SUA. It's still very capable and you will get plenty of flex Link to comment Share on other sites More sharing options...
87MJTIM Posted May 30, 2015 Share Posted May 30, 2015 General Springs in the rear and spacers up front will give you approx 3" Link to comment Share on other sites More sharing options...
egghead Posted May 30, 2015 Author Share Posted May 30, 2015 Thanks for the posts! Looks like I've got a few ideas now. Link to comment Share on other sites More sharing options...
Incommando Posted May 30, 2015 Share Posted May 30, 2015 2WD rear spring packs will net @ 1" less lift on an SOA compared to a stock 4WD pack, but you're still gonna be over 3". XJ shackles would help keep you lower, but may invert.To be technical, a SOA will lift any MJ, 2WD or 4WD, about 5-1/2 inches. If a 2WD starts out 1" lower than a neighboring 4WD, after both undergo a SOA they will both be lifted by 5-1/2" (+/-) and the 2WD will still be 1" lower than the 4WD. The amount of lift from a SOA is the sum of 1x perch offset ~ 1/2" 1x axle tube diameter ~ 2-3/4" 1x perch offset ~ 1/2" 1x leaf pack thickness ~ 1-1/4" Add that up and you get 5 inches as a minimum lift. Pretty much . I got 5.5" going SOA. Link to comment Share on other sites More sharing options...
ggcnash Posted May 30, 2015 Share Posted May 30, 2015 Very happy with Hellcreek springs Link to comment Share on other sites More sharing options...
Pete M Posted May 30, 2015 Share Posted May 30, 2015 fwiw here's a pic showing the SOA measurements: or if it's easier to visualize it this way: Link to comment Share on other sites More sharing options...
daking Posted May 31, 2015 Share Posted May 31, 2015 Great picture! Gave me a great visual. And made me just realize some things. I've always wondered why some trucks had SOA, and some had SUA (all brands / types). Spring over axle never made sense to me. However, after seeing this image, I can see some design benefits of SUA. Mainly, on a drive axle (powered axle, like a rear end), a SUA should have much less wheel hop. Cause the axle housing will have less leverage over the spring. And the spring eyelets will be near equal with the housing. Humm. wondering if I should convert my Race RAM rear to SUA, to help control wheel hop under extreme acceleration... Link to comment Share on other sites More sharing options...
Pete M Posted May 31, 2015 Share Posted May 31, 2015 my guess is that it's usually done for packaging reasons. consider that the MJ is SUA and the XJ is SOA, but the Ranger is SOA and the Explorer is SUA. Either design works just fine for a factory suspension. Link to comment Share on other sites More sharing options...
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