I'm re-doing my front suspension(again) :rolleyes:

Anyways, I am trying to figure out what length of shackle would be considered TOO long in terms of leverage and/or bending the shackle(I've already got an estimate length).

On a stock FJ40, the shackles are a little under 3 inches long. On my reworked front suspension, the shackle I need is about six inches long. I came up with six inches by having the full weight of the rig on the springs with an 1.5 inch spacer between the spring and frame... then I measured. The shackle tube goes through the frame.

Is 6 inches considered TOO long? Will it cause bent shackle or ripped frame problems?

Yes, I did a search. No, I did not find a good answer :(

Thanks in advance,
John

Longer shackles will put more strain on the frame as there is more leverage. The longer shackle can also allow the spring to twist more. How long is too long is hard to say, I run 6" shackles in the rear 4" up front. Up front longer shackles can affect the caster by tilting the axle forward or back. I guess you'll have to experiment to find what works best for your setup, but under 6" is safe.

Joe

I run 5 1/2" front and rear with no problem...it all depends if you did the shackle conversion yet...if not keep it short say 4"....

jdjanda,
Caster and pinion angle are not an issue right now since the front axle spring pads are loose. I'm going to take care of the axle once I get the springs worked out :p

The shackles are going through the frame and are re-inforced but I'm still a bit concerned on it:(

Coyote,
I'm reversing my shackle reversal. (More issues fixed by going back to stock than leaving it reversed) The shackle will be going through the frame about as low as I can go.

My shackle angle is going to end up being around 50 degrees or so when my rig is at rest. My springs are almost flat and only have about half an inch of fore to aft movement before going perfectly flat.

be a man and run some serious shackles i run 12 inch shackles all the way around raked real back and it rides real nice and flexes to all hell

FearMe posted pics of some pretty long shackles on his Ford, back before the software change. I think he was around 8" as I recall. Might be worth it to PM him and see how they're doing.

hey lil jon, not to change the subject too much, but what did you decide on the rear?? did you go with the L shape? in one of the 4 wheel rags, there is a little bit on a rig with L shackles and adjustable ride height via pins, check it out, looks just like what you were talking about(shackles)
and on the long shackles, 6" is no prob, actually its a real nice length, you might want to think of a brace in the middle, i know i know you get more flex w/o, but that brace helps stiffen things up for the side loads on the frame by keeping the bushes square in the bores, a fair trade-off for the small amount of flex. really small

Originally posted by RHINO
hey lil jon, not to change the subject too much, but what did you decide on the rear??


For the rear suspension, it is just a standard spring over with a buggy spring setup(aka 3/4 eliptical) I still need to get an axle limiting strap, a shackle limiting strap, and a buggy pin up system so I can prevent some of the common buggy spring problems.

Originally posted by RHINO
did you go with the L shape? in one of the 4 wheel rags, there is a little bit on a rig with L shackles and adjustable ride height via pins, check it out, looks just like what you were talking about(shackles)


On the front, I'm not sure what I'm doing yet with the shackle(I still have to worry about the front bumper design) I'm hoping to get a prototype of the shackles done this weekend(after I go fawk around at Hollister tomorrow) Right now, I am finishing up the through the frame shackle mounts(damn low duty cycle welder)

The front shackles are going to be in the "rock ram" position(ie stock FJ40 orientation) and will probably take a beating :(

The reason I'm looking at an L shaped shackle is because I've got the front of the spring sticking out an inch beyond where my front bumper is going to end while the shackle mount is about 2-3 inches back from there. I'll snap a side picture and post the "final" result on Sunday so you can visualize it(no bumper yet)

Originally posted by RHINO
and on the long shackles, 6" is no prob, actually its a real nice length, you might want to think of a brace in the middle, i know i know you get more flex w/o, but that brace helps stiffen things up for the side loads on the frame by keeping the bushes square in the bores, a fair trade-off for the small amount of flex. really small

I'm looking at using at least 3/8 inch steel for my shackles and may opt for 1/2 inch steel just for total overkill :p (I've bent one too many stock FJ40 shackles)

I'm also going to look at a way to make them more slider like.

Hopefully this will pan out the way I expect. OTOH, won't be the first time a project has gone FUBAR :)

For the rear suspension, it is just a standard spring over with a buggy spring setup

thats right i remember.
on the front before i went SR, i had a few ideas to make a sort of ramp comming off the bumper to protect the shackles from rocks. one plan was to cut a peice of 3" square tube diagonally, triangular, and weld it to the bottom of the bumper, the spring then would be able to go in and out of this while flexing and rocks, in theory would ramp this and not hit the shackle/spring eye. make any sense??