Shackles in front vs back question

[The_Dealer]

well i was checking out some sas builds and i noticed alot more people have the shackles in the back SRS style then in the front stock jeep style. i understand the principals behind the srs and how it improves ride and handleing because its not trying to push the axle forward on bumps

anywas most of the setups ive seen, which dont have gawdawful tall front spring hangars, tend to look like this

see how angled the spring is.

now im wondering isnt this a bad thing? i know that a shorter shackle would help it out, and i know that the axles caster is dialed in before welding on the perches. but could this be bad? it seems like to me the tire will want to push even farther towards the rear of the rig over a srs with a level spring, which wants to push back anyways.

i was just wondering if it hurts anything for the spring to be like that, or make it handle funny. and what someone could do to mount the shackle in the rear like that without having a huge drop hangar in the front.

 

[ThatGuy]

Its like that because of the step in the frame. The front is higher. If you didn't want a dropped hanger in front you could either outboard the springs or box the frame where the shackle is and put the shackle through the frame.

Personally, I'd do it the easy way and use coils. Oh wait, I did.

 

[dangerranger83]

Personally, I'd do it the easy way and use coils. Oh wait, I did.

x2

 

[The_Dealer]

im not even sure what i want to do or how i want to do it. i was just wondering what are the downsides of a setup like that. he does have a pretty long shackle on it and a stock rbv shackle will improve that drastically. and i know about outboarding. thats how i did my yj when i went 1 tons. real big pita, but the outcome was nice, alot more stable, and i kept my overall cog low...er lower then it woulda been

 

[dangeranger01]

If your set on leafs, then mount the shackle in the frame like an SAS toyota. Box the frame, weld a tube in then put a bushing in it and mount the shackle. Or do it the easy way and use coils.

 

[bobbywalter]

well i was checking out some sas builds and i noticed alot more people have the shackles in the back SRS style then in the front stock jeep style. i understand the principals behind the srs and how it improves ride and handleing because its not trying to push the axle forward on bumps

anywas most of the setups ive seen, which dont have gawdawful tall front spring hangars, tend to look like this

see how angled the spring is.

now im wondering isnt this a bad thing? i know that a shorter shackle would help it out, and i know that the axles caster is dialed in before welding on the perches. but could this be bad? it seems like to me the tire will want to push even farther towards the rear of the rig over a srs with a level spring, which wants to push back anyways.

i was just wondering if it hurts anything for the spring to be like that, or make it handle funny. and what someone could do to mount the shackle in the rear like that without having a huge drop hangar in the front.

what you have there is what not to do.

that has to ride horribly. but maybe not if the adjusted the c's to proper caster. could ride great...but i dont see how.

the spring is best level as possible. i put them in the back and the front.

mine are out front at the moment as i went to chevy 52's. i like the ride better in the back but i wanted to change the ride height and front shackles facilitated that a lil better. i run a track bar too depending on what tires i use. the 44's or 42's i let it float. with 33's or 35's i put the bar on. been letting it hang with the 37's but will pop the bar on again and play with it.

 

[The Jester Race]

With the shackles in front you get a lot of bump steer, in my case it was so bad it threw it into a death wobble. If the truck is going to see much pavement I suggest a rear shackle setup, but if its a trail only truck it really doesn't make any difference.

Here is mine

What are you trying to accomplish? A full blown crawler? Mild SAS build? How much lift? What size tires? Are you dead set on leaf springs or would coils be better for what you want to do?

-Jester

 

[The_Dealer]

it will see some dd usage, coils isnt really gonna be a big benefit for me. i do know more about leaves then setting up a coil suspension, plus the trac bar issue kinda scares me, if its not right it will drive like shit. im wanting 35's not real sure on the axles yet, i would like f/w but will prolly be overkill for what im going to do with it. i really like the way yours is setup, do u have a build thread on it?

 

[The Jester Race]

Thanks. No I dont have a build thread. I wanted to do one but I kept forgetting to stop and take pictures. I do have some pictures, but not enough to do a build thread. If you have any questions or want more pictures feel free to ask.

-Jester

 

[The_Dealer]

u have any pics of how u mounted the shackle in the rear? i saw alot of vendors on pirate4x4 as well as ballistic fab and ruffstuff all make 2.5" hangers and stuff i could use to make it go easier. i like the tube mounted in the notched hanger deals that that have for a shackle mount. save me alot of time on fabwork. since it is my dd i need to have it driving within a long weekend or so. not near as long as it took me to get all my stuff to do the fm146 swap lol.

EDIT: i also like how u dont have a huge drop xmember in the front like alot ive seen. how long is your shackle? also how long and how much lift are your springs?

 

[The Jester Race]

I just copied these CLICK, then welded them to some 1/4" plate to mount them outboard of the frame, then welded some 1/4" gussets to the frame. My shackles are made out of 3/8" strap, and the holes are 4.5" on center.

For the front I used a piece of 2x4 1/4" wall tube for the cross member and some 3.5" OD 1/4" wall square tube to make the hangers. I made all my cuts with a 4.5" grinder.

I used Rancho 44150 springs with one medium length add-a-leaf, spring rate of 250lbs. If I remember right they are 4" lift rear jeep wrangler springs. They were laying around my dads shop and he said I could have them, so thats what I used . Without the add-a-leaf they were too soft and were almost flat at ride height. Over all my suspension is about 8" of lift.

I think your are a little ambitious to try and do a SAS in a weekend but if you plan right and have everything ready to go it might be possible. It took me 3 months(weekends only)to do mine, but mine fought me every step of the way.

-Jester

 

[bobbywalter]

-Jester

ahhh...and a pic of beauty in my eyes we have here in the same thread.

my guess here is a well balanced decent handling machine with great ride on and off road. of course, again i could be wrong here.

awesome work jester i likely would have slid and tacked in a support in the rectangle spreader...not sure if you did that or left the boxing as plenty strong. with a 2.9 and d 44 as the unsprung it certainly is.


curious to the death wobble issues, i actually see less of that shackles forward when caster is 5-8 deg.

 

[The_Dealer]

sweet thanks jester. seems like im gona copy u. the springs i have gave me about 3.5" in my yj with a 383. was pretty much a basterdized superlift pack. what axles are u running?

 

[t0x1k]

I saw this on Trucks or some show. It allows the tires to clear obstacles better by allowing the tires to jump and and backwards and when going forward allow the tires to "hop" over things unlike the jeeps which cause the tires to move forward and push away from the object.

 

[The Jester Race]

i likely would have slid and tacked in a support in the rectangle spreader...not sure if you did that or left the boxing as plenty strong. with a 2.9 and d 44 as the unsprung it certainly is.

I have no idea what you are talking aboutEDIT: Oh ok, I reread that and get what you're saying.

i likely would have slid and tacked in a support in the rectangle spreader

Wait I still don't know what you are talking about here.

But thanks. It took a lot of time and work, a lot of trial and error. Seems like I did everything 3 different ways before I got it right. But I am happy with how it turned out, not bad for my first build. It rides pretty well on the streets, definitely no worse then stock, and from the little offroad it has seen(so far) it handles pretty well(Still waiting on front driveshaft).

The death wobble was caused by me being a cheap bastard. Not spending the money and setting it up for crossover highsteer the first time. Instead I went with the funky ass setup that was on the axle when I got.
As seen in this picture

I originally planned on running a front shackle setup, and built it and had my truck "done". Then I took it for a test drive with a shit eating grin on my face. I could not stop smiling, I just finished building my first crawler, I was more exited then when I lost my virginity. When I experienced a very bad case of death wobble. With the front shackle setup when I hit a bump, as the suspension dropped it would "roll" about 5 degrees of caster out of the axle, when it was set up with 6 degrees of caster. Which combined with a funky ass steering setup threw me into "oh shit" wobbles. Without the funky steering it would probably of been a very sever bump steer.

With how it is set up now, steering and rear shackles, there are no problems what so ever, just a little bump steer here and there, but thats expected with a solid axle and a steering stabilizer takes care of that.

I used a high pinion Dana 44 front and a Dana 60 rear out of a '79 F-250(Full Width).

I really do appreciate the compliments, sometimes my OCD pays off.


-Jester