when climbing a ledge, the axles in under compression when set up properly, it will not be drooping at that point
Front shackle reversal
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With the SOA your double cardan joint is probably close to binding at full droop - assuming it's a stock driveshaft. A shackle reversal will increase the drveshaft angle even more and you might have to modify the tranny crossmember for driveshaft clearance as well.1985 GW, 360, 727, NP229, D44, AMC20, HEI, SOA/shackle flip 7" lift, Quick Lok locker rear, Aussie Locker front, 4.10 gears, 37 X 13.5 Interco SS-M16's, Warn Premium hubs, Tuff Stuff 12,000 LB winch, rear disc brakes === stripped down street legal off road toy
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Originally posted by billyj7175I'm no engineer, but I did see that in play as he couldn't climb obstacles that he could clear before the shackle reversal.
I love my reversal. Sure, I had to deal with building a custom driveshaft and more significant pinion angle change, but it's worth it, IMO. I mean, look at every single Toyota. Shackles in the backs. And Toyotas are arguably the best vehicles to build into a "budget" hardcore rig (How dare I say that, i know!).
Aside from crawling, the reversal made the biggest difference in the world while mashing thru the desert. My truck likes whoops.
Typically, the hard mounted end of the leaf spring sees about 70% of the load. So, when you hit a rock, you are putting the spring in compression where it is likely to bend. However, when you reverse the shackle, the hard mount is at the front of the truck, and the spring will basically be in tension, where it is less likely to fail.My 1977 J10 on 1tons and Krawlers
If you wheel on the west coast or you hit the Hammers, look for my crew, the PolyGoats: www.polygoats.com
Poundcake!
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Originally posted by onesunJ10I've wheeled both set ups, and, as an engineer, the forces really aren't different. Dynamically, they may act differently initially, but the suspension isn't going to continually move away or towards the obstacles. What i am trying to say is after the initial movement (compression/droop) the suspension is settled and it's not goinig to continually move "away from the rock". It can only move so far. There are so many factors that influence how a truck crawls, and if my shackle reversal made my truck crawl worse, i sure didn't notice.
I love my reversal. Sure, I had to deal with building a custom driveshaft and more significant pinion angle change, but it's worth it, IMO. I mean, look at every single Toyota. Shackles in the backs. And Toyotas are arguably the best vehicles to build into a "budget" hardcore rig (How dare I say that, i know!).
Aside from crawling, the reversal made the biggest difference in the world while mashing thru the desert. My truck likes whoops.
Typically, the hard mounted end of the leaf spring sees about 70% of the load. So, when you hit a rock, you are putting the spring in compression where it is likely to bend. However, when you reverse the shackle, the hard mount is at the front of the truck, and the spring will basically be in tension, where it is less likely to fail.
Someone ask Cappa if HotDot was a POS...
Get ahold of these guys, they have a kit they sell.... and HEY, THEY RACE FSJs Too:
Now... do make sure your suspension doesn't travel aft more than your driveshaft or you will be sadly disappointed with the results... but heck you can SOLVE THAT WITH FOUR BOLTS.... simply flip your FSJ springs around. The fronts have a 2" offset (and then work in some steering corrections to account for it or you'll be jamming your tie rod into your pitman arm... or maybe not since it all moves aft now).Last edited by Elliott; 02-13-2010, 07:12 PM.*** I am collecting pics and info on any factory Jeep Dually trucks from the J-Series at the new Jeep Dually Registry.
***I can set you up with hydroboost for your brakes: http://www.ifsja.org/forums/vb/showthread.php?t=106056
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It is quite possible that (mind you, I was referring to Samurai's), he wasn't hitting the obstacle hard enough.
Now that I think about it, his tighter turning was most likely stemmed from running a 2" longer shackle in the original configuration...with the S/R, his caster was probably back in spec, (or possibly beyond).
Elliott: That's some good info on the spring center difference.83 J-10 Jeep "Oscar"
360/727/229
4" Rusty's w/33X12.50 BFG AT's
I'll apologize ahead of time...my inner voice has Tourette's...
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The 2" offset... that would probably not be a problem on spring reversal with shackle reversal. If you flip the springs around on a normal rig you will have trouble on compression but with the reversal... seems like you'd be clear.
On another note, I guess if you found the braking conditions to be undersireable (although 900Lbs over my front >flat< as in no arch springs isn't a problem for me on the F350<) I would think that installing an adjustable proportioning valve would help you dial it in to your liking better.Last edited by Elliott; 02-13-2010, 07:47 PM.*** I am collecting pics and info on any factory Jeep Dually trucks from the J-Series at the new Jeep Dually Registry.
***I can set you up with hydroboost for your brakes: http://www.ifsja.org/forums/vb/showthread.php?t=106056
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I have BJ's 6" lift with the drop pitman arm on my 85 GW. Can I just flip the springs around and do a shackle reversal without other mods?1985 GW, 360, 727, NP229, D44, AMC20, HEI, SOA/shackle flip 7" lift, Quick Lok locker rear, Aussie Locker front, 4.10 gears, 37 X 13.5 Interco SS-M16's, Warn Premium hubs, Tuff Stuff 12,000 LB winch, rear disc brakes === stripped down street legal off road toy
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I mean, look at every single Toyota. Shackles in the backs. And Toyotas are arguably the best vehicles to build into a "budget" hardcore rig (How dare I say that, i know!).and, as an engineer,
This question is just like the, "Do I switch to a SBC question"....The bottom line is,, knock yourself out. It's your money and time.
J20BP Drivetrain...........
Driveshafts for all Jeeps, Constant velocity rebuilds, Replacement, Repair
775-537-7918
https://www.facebook.com/BPShafts/
Putting this back up. "Someone is gonna have to crawl under the rig"
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Originally posted by Dirt WagI have BJ's 6" lift with the drop pitman arm on my 85 GW. Can I just flip the springs around and do a shackle reversal without other mods?*** I am collecting pics and info on any factory Jeep Dually trucks from the J-Series at the new Jeep Dually Registry.
***I can set you up with hydroboost for your brakes: http://www.ifsja.org/forums/vb/showthread.php?t=106056
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No, not without centering the axle in the well. So, the front hanger will have to be dropped approximately 4" and the rear shackle mount will have to be moved as it will now attach to the long end of the spring. Im going to be doing this soon on my J15 and will have a square cross tube with the hangers welded unto it. This tube will provided lateral support to the hangers and more area to attach the hangers to the frame.
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Originally posted by J20 projectMan, these are just begging to be hammered..LOLMy 1977 J10 on 1tons and Krawlers
If you wheel on the west coast or you hit the Hammers, look for my crew, the PolyGoats: www.polygoats.com
Poundcake!
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I stand corrected, the steering box sets bellow the frame rail preventing a cross bar unless it sets infront of the mount. Hmm? Im still going to need a 4" drop in front to correct the caster. Or use wedges??? Buy at www.rocklaurencevintageautoparts.com
I now have a bolt in kit: RockLaurence vintage auto parts and I have a store on Ebay
Last edited by rocklaurence; 05-12-2015, 07:42 AM.
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OK, this is the Universal Heavy Duty Slider Boxes that I have listed on my store. The one for the FSJs will be the same with the addition of a side plate to locate the brackets via the two lower transmission crossmember bolts. Ill be putting that together soon. https://rocklaurencevintageautoparts.co ... de-springs
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I have the Rocklaurence FSSR kit on mine and I love it. (probably close to 5k miles with it). I originally had it with stock springs, now have Rancho lift springs.
Some notes for anyone considering it:
1) You will need to have your front driveshaft lengthened and/or have a long travel yoke added.
2) I was able to keep my stock brake lines but moved the bracket that holds the fitting where the soft lines meet the hard lines down a notch.
3) When you brake, the truck does nose down a bit more than it used to. It feels like the front brakes are doing all the work but they are not; it's just the physics on how the springs work now. Again, not really a problem.
4) the centering of the axle does not really end up being a thing. At least I don't think so. You would be hard pressed to tell the difference before and after install. If you REALLLLLY look at before/after pics, you can see it moved but it's not enough to really be an issue.Chuck McTruck 71 J4000
(Chuck McTruck Build Thread)
(8.1L swap questions - PerformanceTrucks.net Forums)
79 Cherokee Chief (SOLD, goodbye old buddy)
(Cherokee Build Thread)
11 Nissan Pathfinder Silver Edition 4x4
09 Mazdaspeed3 Grand Touring
00 Baby Cherokee
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