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General Forums => The Mess Hall => Topic started by: neale_rs on January 29, 2008, 05:07:47 PM
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This question is mainly for oldjeep but it would be good to get any and all opinions from members.
oldjeep,
You have an SUA YJ. With your mechanical and fabrication skills you could set up your jeep with SOA about as easily as anybody. What are you reasons not to do so?
Thanks
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Probably axle wrap, a friend of mine has a CJ7 with a 4.5" lift on it and he has a heck of a time keeping his Jeep on the road. The thing wanders from the rear accelerating/decelerating
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I like BOTH... :wall:
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SOA on my YJ, now have to add traction bars to contend with the axlewrap. I didn't think the 2.5L would twist the axles much, maybe it's the 5.38 gears :smokes:
I run relatively flat springs, I like the added lift of SOA without having to run stiff arched springs.
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This question is mainly for oldjeep but it would be good to get any and all opinions from members.
oldjeep,
You have an SUA YJ. With your mechanical and fabrication skills you could set up your jeep with SOA about as easily as anybody. What are you reasons not to do so?
Thanks
Pro
1) SOA will tend to be a more flexible and gives you some more ground clearance at the springs
Cons
1) it's also a lot harder to make it behave on the highway.
2) Cost - everyone who has never done an SOA says they are cheap, just put the axles under the springs and go. BS. You need to address the steering problems, generally with a high steer setup. You need a rear traction bar or you will be destroying springs, driveshafts and pinion yokes.
It's very easy to set up an SUA YJ and make it work safely and reliably, and if you are going to be driving it at 75 MPH those are important things.
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Thanks for all the replies. I'm going with SUA. My main reason initially was to avoid fabrication and having to work out all the complications of SOA. Since the YJ will be driven on the highway to get to trails it sounds like SUA was the better choice for me.
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My SOA YJ drives just fine down the interstate at 80mph.
You would need to do the same mods between the SOA and SUA if using the same amount of lift, minus having to weld on spring perches. Comparing apples to apples here and not comparing a 6" SOA lift to a 4" SUA lift. You can get away with a lot fewer mods at 4" regardless of the type of lift.
A SOA will outperform a SUA lift any day, a flatter spring has a much larger operating range and a better onroad ride.
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I really didn't want too much lift, just enough for 33s. I have a few jeeping buddies who run SOA and also say it is fine but they have complained about lean on off-camber slopes.
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My SOA YJ drives just fine down the interstate at 80mph.
You would need to do the same mods between the SOA and SUA if using the same amount of lift, minus having to weld on spring perches. Comparing apples to apples here and not comparing a 6" SOA lift to a 4" SUA lift. You can get away with a lot fewer mods at 4" regardless of the type of lift.
A SOA will outperform a SUA lift any day, a flatter spring has a much larger operating range and a better onroad ride.
Out of curiosity, what did you do to your steering when you went SOA? In otherwords, where is your tierod?
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My tierod was initially under the springs, now it is over the springs with BTF highsteer arms.
With it and my draglink under the springs I had too much bumpsteer, same problem you would have with the same amount of lift SUA.
SUA is a good choice for 4" of lift and 33" tires. I'd even recommend 2.5" springs and TJ flares to keep the center of gravity lower.
IMO for 35" tires and larger, SOA is the best route. I was installing D44's anyway (needed for proper gearing) so SOA was logical.
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My tierod was initially under the springs, now it is over the springs with BTF highsteer arms.
With it and my draglink under the springs I had too much bumpsteer, same problem you would have with the same amount of lift SUA.
SUA is a good choice for 4" of lift and 33" tires. I'd even recommend 2.5" springs and TJ flares to keep the center of gravity lower.
IMO for 35" tires and larger, SOA is the best route. I was installing D44's anyway (needed for proper gearing) so SOA was logical.
So you've got a Dana 44 in the front, not a dana 30. This is how most SOA vs SUA discussions start, when the guy with SOA forgets about all the mods that he did before switching to SOA. And by your own admission, you've currently got an axlewrap problem in the back - which is a common problem when people do a partial SOA conversion.
Bumpsteer on a SUA YJ with 4" lift is solved with a drop pitman arm or tierod flip. Although with a 4" SUA lift 5/8" shackle lift and stock steering, mine is decent enough on the highway - with plans for a tie rod flip. 4" SUA, 5/8" shackle lift and TJ flares is plenty for 35" tires and is a nearly bolt on setup.
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Hmmm, I see there are some misconceptions with SOA's.
If you''re already lifted 4" or more then a SOA is fairly simple to install since you won't be gaining that much more height. When I decided to go SOA on the front of my Jeep, it cost me $30 for the perches and $150 for two stock leafs springs. Everything else was carried over from the SUA.
Steering is no different SOA or SUA. The only real difference is that the SUA is going to be stiffer so it moves less. But that's because of the leafs and not because of any corrections to the steering geometry. Because of this, you will see more bumpsteer then with a SUA generally speaking. Now if you raise the spring rate of the SOA, it will reduce the bumpsteer. Adding a trackbar to the front will help a lot since that really stiffens up the front. I'm just running the stock arms with a dropped pitman arm currently.
The rear? Well, I didn't want to deal with axle wrap so I kept it SUA. It flexes a bit less then the front but it's not bad at all. Otherwise, adding a extra main leaf to the stock leafs would help alleviate axle wrap. If you really wanted to do it right then getting some SOA springs from Rubicon Express would probably be best. At least for an off the shelf solution.
As for highways, you adjust to it. Although with my SOA/SUA setup, it's a bit more surefooted then if I went all the way. With the sway-bar attached, the front is well behaved. 75mph is smooth and tracking is fine. Emergency braking could be a bit better but that's fixed with high-steer.
Offroad, though, it's a big difference. The front actually flexes. Instead of three wheeling, you'll have 4 down. The ground clearance is a big plus. If you do rocks, you'll be dragging your leafs. This is actually a problem with SUA's that have custom leaf packs. To get a softer ride but have the added spring rate of a thicker spring, they have to use thinner leafs but more of them. The problem this causes is the spring pack can get rather big. If you look at some older Jeeps that have National Springs leafs, you'll see they are usually 9 leafs to a pack and are huge. They flex really well and ride smooth though.
Although you're really opening up a can of worms, asking a person to defend their choice. It's a personal choice and is really dependent on their local trails as much as a personal preferance.
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Jeffy, Have you got a picture of your tie-rods in relation to your springs? Every SOA YJ I have ever seen that uses the stock YJ steering has the tierod or drag link hitting the leaf spring when flexed out. How did you get around that?
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This is what I was looking for. What happens when you crank the steering to the right and stuff either front wheel? Have you got the perches jacked up enough or the knuckles tiped back so that the draglink doesn't hit the spring?
(http://i4.photobucket.com/albums/y118/yokomura/1992-2007/2003h.jpg)
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This is how most SOA vs SUA discussions start, when the guy with SOA forgets about all the mods that he did before switching to SOA.
D44's were at the SAME TIME as the SOA, which made the swap that much easier.
When I had my draglink under the springs, it did not contact the spring pack when at right full lock. I was using Waggy steering linkage and GM knuckles where the tierod goes into the steering arm from beneath. Couldn't use the Waggy knuckles because the TRE's go in from the top.
Rear axlewrap isn't much of an issue for me to avoid the advantages of SOA, it's easy to deal with. Just unexpected. And I'm using stock YJ spring packs with an additional full-length leaf in each pack. I cut the extra leaf half-way through the spring eye so it wraps up the spring eye of my existing spring pack, giving good support to the weakest part of the main leaf.
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Oh, I run no swaybar or trackbars, highway use is just fine.
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This is what I was looking for. What happens when you crank the steering to the right and stuff either front wheel? Have you got the perches jacked up enough or the knuckles tiped back so that the draglink doesn't hit the spring?
(http://i4.photobucket.com/albums/y118/yokomura/1992-2007/2003h.jpg)
It clears fine or else I wouldn't not have done it. The guy who helped me set mine up runs his the exact same way.
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It clears fine or else I wouldn't not have done it. The guy who helped me set mine up runs his the exact same way.
Couple questions for you, I'm trying to add some tech to this thread.
1) Did you do anything special to make it work, or is that pretty much stock YJ springs with normal height perches?
2) What kind of terrain do you wheel in? The picture does point out another reason why SOA should have high steer. Now instead of having springs to ramp the rocks, the tie rod and drag link is the first point of contact. For forest trails, it wouldn't matter much - in the rocks it wouldn't last long.
I'm not trying to be an a-hole, but I've seen that setup not work in person many times.
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The springs don't contact as much as the middle of the axle does, since they're tucked up behind the wheels. Thus the draglink (at the middle of the axle) would be at the same level and risk of contact regardless of SOA or SUA.
You can see a little of my steering here:
(http://sija.org/bounty/Redbird07/DSCN5703.JPG)
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Couple questions for you, I'm trying to add some tech to this thread.
1) Did you do anything special to make it work, or is that pretty much stock YJ springs with normal height perches?
2) What kind of terrain do you wheel in? The picture does point out another reason why SOA should have high steer. Now instead of having springs to ramp the rocks, the tie rod and drag link is the first point of contact. For forest trails, it wouldn't matter much - in the rocks it wouldn't last long.
I'm not trying to be an a-hole, but I've seen that setup not work in person many times.
Nothing extra ordinary BUT you have to choose the right spring perches. I'm using Rubicon Express which are a bit taller then regular ones. This makes a BIG difference in whether it hits or not. The RE perches are made for SOA specifically. Not to mention they're offset. The picture is a bit deceiving since it's show from low down so it looks closer then it actually is.
Terrain: Rocks, rocks and more rocks. I'm about 3-4 hours from the Rubicon. I don't use my drag-links as feelers. It takes a bit more thinking but then you put the tire on the rock and not straddle it. It's really no safer then SUA though since you can get punched in the center if you try to straddle a rock. I could raise the tie-rods, if I wanted to put some bends in drag link but I haven't had any problems with it.
High steering would be nice but it's a waste for a D30 when you don't plan on keeping it forever.
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You can see a little of my steering here:
(http://sija.org/bounty/Redbird07/DSCN5703.JPG)
Slightly off subject, but what size are those Swampers Bounty Hunter? I like your front flares :thumb:.
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High steering would be nice but it's a waste for a D30 when you don't plan on keeping it forever.
Definitely - considering what high steer for a D30 costs. You could do a d44 swap with high steer for that money ;)
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Slightly off subject, but what size are those Swampers Bounty Hunter? I like your front flares :thumb:.
Q78, which is 35.5"x10.5" with 27/32" tread which is only second in depth to the bogger. The Q78 is close to the 36"x12.5", just a little skinnier with deeper tread. I like pizza cutters.
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Definitely - considering what high steer for a D30 costs. You could do a d44 swap with high steer for that money ;)
This brings to mind the following setup with D30 front axle:
SOA in rear
SUA in front with a tie rod flip to get the steering up higher (I don't think this can be done with SOA in front)
Do you think it would have a significant advantage over straight SUA?
Any significant advantage over Jeffy's SOA/SUA setup?
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This brings to mind the following setup with D30 front axle:
SOA in rear
SUA in front with a tie rod flip to get the steering up higher (I don't think this can be done with SOA in front)
Do you think it would have a significant advantage over straight SUA?
Any significant advantage over Jeffy's SOA/SUA setup?
I don't think there would be any advantage to doing an SOA only in the rear, unless you were just doing it as a half step on the way to a full SOA. The clearance gain wouldn't help much since the front is still down lower, and you would have to put in a traction bar to keep the wrap under control.
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This brings to mind the following setup with D30 front axle:
SOA in rear
SUA in front with a tie rod flip to get the steering up higher (I don't think this can be done with SOA in front)
Do you think it would have a significant advantage over straight SUA?
Any significant advantage over Jeffy's SOA/SUA setup?
That would be the worst way to go. With the SOA in the rear only, you'd have to deal with axle wrap which isn't so easy to solve. SUA in the front would be no doubt be stiffer up front so your ride would suffer as well as your flex. Most crawlers have more flex up front then in the rear anyway. Off the shelf traction bars don't work well. Of the guy's I know who tried that route, ended up going custom since those bars kept breaking. The one setup that really works though is the 'BamBar'. It's a multi-linked shackle sort of thing. It was created by a friend of mine. You can see it here http://www.jeepaholics.com/tech/bambar/
You really need to plan out a SOA and research it well. Talk to people who've done it.
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Thanks. The bambar looks good. From the geometry it looks like it would induce a bit of squat instead of anti-squat and the main problem would be having enough space under the tub, might require a body lift.
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My SOA YJ drives just fine down the interstate at 80mph.
I am not sure I would even drive a stock Jeep at 80mph... I try to keep it under 75, but that's just me.
You would need to do the same mods between the SOA and SUA if using the same amount of lift, minus having to weld on spring perches.
If you plan to install a CV shaft, you will end up having to weld anyway. Otherwise, you wont be able to drive at more than 20mph cause the jeep will shake more than a San Francisco earthquake! Trust me on this one, and dont ask me how I know!!!
My main worry in the case of SOA is sprig warping... Bounty, how's this issue been for you?
This brings to mind the following setup with D30 front axle:
SOA in rear
SUA in front with a tie rod flip to get the steering up higher (I don't think this can be done with SOA in front)
Do you think it would have a significant advantage over straight SUA?
Any significant advantage over Jeffy's SOA/SUA setup?
I was in the same dilema, and although I know the SOA will outperform the SUA, I decided to go with the SUA for convenience. But knowing what I now now, I would probably have gone SOA in the front and SUA in the rear... And if possible, i would swap to D44s... This will allow you to have more options in the future, like better gearing for bigger tires, and more strength at the axles.
Felipe
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My main worry in the case of SOA is sprig warping... Bounty, how's this issue been for you?
Are you talking about spring sag? My stock springs +1 AAL haven't sagged any, but I extended the bumpstops to limit uptravel, thus making the springs last longer. Repeated over compression will wear them out quickly.
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Well I run a SOA setup.... I believe it is far better than my old 4.5" RE SUA Kit.... But it did cost more to get it right.... We streched the wheel base about 3" also....
Superlift 1.5" Springs - RE Spring Mounts - MORE Bomrangs - TeraFlex HSK - Sams Offroad HD Traction Bar
Ive got a few pics:
(http://oakey.net/FTP/JEEP/YJ_5.jpg)
(http://oakey.net/FTP/JEEP/tb1.jpg)
(http://oakey.net/FTP/JEEP/YJ_1.jpg)
l8r,
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Which end did you stretch and how?
Thanks for the traction bar pic, how's it working out for you?
Looks like your rear springs are about shot, looking past the traction bar. Definitely don't look like 1.5" springs unless that was before the springs.
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My YJ is now lifted SUA (just since Friday). First time out on the trail, trying to get up on a rock, the front spring hits the rock (not hard) half way between the shackle and axle. On a SOA YJ, the rock would have slipped under the spring, hitting either the tire or the tie rod first. Could have been better or worse. For now, I'll have to wait until I have more experience with the lift to better understand the tradeoffs.
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Which end did you stretch and how?
Thanks for the traction bar pic, how's it working out for you?
Looks like your rear springs are about shot, looking past the traction bar. Definitely don't look like 1.5" springs unless that was before the springs.
I pushed the front axle out 1.5" and the rear the same by redrilling the spring plates and flipping the springs around..... Those springs have been replaced now.... I should have kept them since they were flat.... The flex was GREAT..... But the new springs work GOOD too....
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Are you talking about spring sag? My stock springs +1 AAL haven't sagged any, but I extended the bumpstops to limit uptravel, thus making the springs last longer. Repeated over compression will wear them out quickly.
Sorry, I meant spring wrap... The bending (in an S shape) of the spring as you accelarate.