Flex with a rear end ZUK mod
 

So let's just talk about this because this is kinda bugging me. So the zuk mod is jeep springs put between the bump stops on the rear end in turn leveling out rear sag and a bit of a lift as well. I have no bumper or tow bar so my rear end sits about 3 inches above stock just because of the springs. But now if my rear end is going over anything the other side won't travel up making my rear end super stiff and not really flex over obstacles. This is just theory I can't really say I can watch it happen but I almost rolled it the other day and my rear end driver side was about 2 feet off the ground. I know my center of gravity is changed but I'm trying to fix this issue besides doing the sas any help on this should I get diff springs and some new shackles ?

I can't imagine how SAS could affect rear axle flex.

If your rear springs are already so stiff as to restrict rear flex, the addition of ZUK mod springs to the rear axle can only make your issue worse.

Many would say the 63 inch chevy spring mod is the answer.

I'm not clear on what problem you're describing.
ZUK mod is not for everybody, it's simply a band aid to remedy saggy-butt of worn out leaf springs. If you want articulation, this is not for you.
Adding in a coil spring in there is going to prevent you from ever achieving the same up-travel again, simply because there's now an object there that wasn't before. It's going to make you lift more tire on the opposite side since the axle cannot pivot like it used to.

If you want articulation, you need to go back to straight up leaf springs, with a lift of some sort to gain back the height you wanted before. OME and a handful of companies make 2" lift springs as a "stock" replacement, there aren't really any stock height ones available unless you go custom and pay big $. 3"+ is your next option for leafs, sold by many companies but TG is likely cheapest. Shackles can also help add some lift as long as you can keep the angle happy and not invert them when you articulate (1" longer shackle for every 0.5" lift). Both custom leaf/hybrid packs are common mods, as are Chevy leafs. Though the Chevy 63s flex really well and a lot of people use them, I think there is almost equal amounts of people who hate them and would rather put something else on their truck after experiencing the weak points that not many people talk about when they always suggest them to people.

Good luck!

https://cimg7.ibsrv.net/gimg/www.yot...d14458fa00.jpg

the struggle is real. i did the zuk mod to clear the 33's, but it doesn't flex for ˟˟˟˟ now. i've thought about shackles, bastard packing, and chevy 63's. but i'm gonna wait till i finally pull the trigger on the sas

Ok that's what I'm talking about rear end doesn't move for crap because of the zuk mod. I have a buddy who is pretty good at fab work I've been looking for some good springs for the rear. Now I do know with most new/aftermarket springs the hangers need to be relocated. I put in a 1" bj spacers up front so it sits more level but now I really gotta find some better springs so I don't roll my truck before I get to sas it :). Thank you for all the info. I don't really have any wheeling buddy's or buddy's who know anything about cars let alone off road modifications so it really helps. What are some down sides to the Chevy springs ? Too flexy? Having to relocate hangers? My buddy's 85 has lift springs in the rear no idea the brand but because he didn't relocate his hangers he had a inverted angle :( but we popped it back with a hi lift. The zuk mod also caused my stock length shock to snap from down travel so I just got another cheap shock. I have a daughter that's supposed to be born in 3 weeks so I'm not gonna be wheeling much so my truck is just my daily till November around my b day so I have time to work about 1 day a week is what my wife gives me to do me stuff on top of working 50+ hrs. So if I can get parts around town the yards and get it all together a day in my garage makes quite a bit of work fly by.

So let's say that I'm gonna sas my front end in the future and I wana work on the rear because it's really what I need help with. I'm thinking 4 inches of lift and 35s so it sits right on top of the wheels. Are Chevys the way to go or is TG my best bet. I don't think I want a 6 spring pack to keep my rear end lifted I guess that's better then blocks but it'll be so damn stif so I'd like to get some springs that will flex good and will be decent on price

I did the zuk mod on my 4runner with the junkyard jeep tj coils. Actually flexes pretty nice. Guessing the added rearend weight of the topper and such must be enough to get the added spring rate to flex.

I took my tow package off no bumper and no spare underneath think I got almost 3 inches of lift off of it but I think I would have a better lift and better flex with extended shackles seems to me that unless you have a large load in the rear that these springs are super stiff my rear end just slams on and off of everything

Flex with a rear end ZUK mod
 

Different springs maybe? Mine didn't really lift at all just brought the saggy back end up to about level with the front. I used junkyard springs, factory jeep tj rear coils if I recall.

Possibly I got mine off Craigslist for 40 bucks I can't remember if there front or rear. I was surprised how heavy my tow bar was that raised it quite a bit. there snug on the bump stop but like I said I'm thinking of doing a 6" shackle until I can get some 2wd Chevy springs to get the real flex going

I'm pretty sure the front tj springs are several inches longer than rears. Straighter also, the rears are kind of a "barrel" shape if that makes any sense.

Yea totally I think that the Zuk mod is good for getting rid of sag for cheap but for off-roading and flex I think either a shackle lift or some longer softer springs with relocation of the hangers. I've just been looking for a cheaper option my self maybe f150 springs ?

My new to me '88 4rnnr came with this mod done to it. I missed it somehow when looking at the truck, but knew something was up from its ride height. Whomever did it used 2.0 coil-over springs and cut the 'U' brackets that bump-stops hit in 1/2 horizontally.
I'd like to :saw: two people, the guy who did this mod and the guy who came up with the idea. The truck rode like crap (still isn't good with those RS5k's still on there) and you'll never get a good damping set-up with two different spring types involved.

I had 63's under my old '84 Xcab that I just sold. Can not go wrong there, not at all. Flexed very well and also worked extremely well chasing desert racers. Put some remote reservoir 7100's with 275/78 shim stacks in them under it and you're good to go!
I'm trying to keep the 4rnnr lower than the 63's will allow or I'd do them again.

i got pretty squirrely this weekend and I'm rocking an 86 4Runner with original rear leafs and the zuk mod. I have a video up on my build thread that shows its performance. I was pretty happy.