front leaf shackle position

[dirtbag]

I am going to go SAS on my 87 Xtra Cab, and, instead of going with the traditional shackle on the rear of the leaf spring, I want to put them on the front, like a Wagoneer ( I know, Jeep stuff ), but I'll be running a version of Waggy's up front, & Jeep truck rear springs in the back ( the sets of leaves that I have in mind for this have to have a few leaves taken out, since they're made for 3/4 ton trucks ).

Anybody have any reason as to why NOT to do this?

[Hyena]

I have heard that it can be really squarlly because of the shackle in the front.  I don't know if this is true.

[Skinny_Pedal]

yeah i have heard the same thing. isnt that why jeeps have the shackle reversial kits?

[brainlessfool]

there's one out for scouts too. must be a reson   

[Skinny_Pedal]

also if u put the shackle up front your gonna need to match that with bracket for the spring to mount. so your 3rd member isnt angled down. does this make sense?

[dirtbag]

also if u put the shackle up front your gonna need to match that with bracket for the spring to mount. so your 3rd member isnt angled down. does this make sense?

yeah, it makes sense. I just want to see if someone can talk me out of it. I have most of it figured out, & I don't really care about it being squirly, since I have a swaybar I can fab up to mount on. I'll make spring mounts & stuff, it shouldn't be too bad ( I have a good idea of a few designs right now ).

[Skinny_Pedal]

well i would say dont do it, since that is one of the things i know jeepers biotch about!

[Paul_Elbisser]

I have seen this swap at the second BHCC a few years ago.  I'm sure he wasnt the first guy to do it, but you also got to think. If it has been done for more than 3 years now why don't you see more of it?

Simply put when the spring goes from arc to flat, the spring get longer. To properly tune a front shackle you should figure out how much longer it will get, how much swing you need in your shackle to keep the spring going as straight up as posible. But then of course the rear of the spring needs to be a fixed point. How do you get this in the right spot?

The way I look at it it needs to be lower than the axle. So whne the suspention travels down, the spring gets shorter. it will also be closer to the pivot point, so that is close to a straight line down. And when the spring compresses the axle moves up away from the pivot point, when the spring is getting longer.

So in my eyes anything else will make the axle move forward into an obsticle harder.  However if you have the shackle behind the geometry isn't as much of a factor. If the suspention can compress over it.

On the other hand when the axle is moving into the obsticle it is adding more traction to the tire. SO you can make the call. I was mainly just thinking to myself.

[To The Floor]

If you did end up doing that, you could do a lift shackle in front then mount the rear of the front springs close to the frame to help out your pinion angle.   

[Jared]

What in the sam hell are you thinking josh?   

[dirtbag]

What in the sam hell are you thinking josh?   

revolvers

[WHITE_TRASH]

Yup Paul said it and Ill repeat it if need be.  The tires move in a natural "absorbing" type of arch when the shackles are in therear of the axle.  When you put the shackles in the front of the axle the axle is forced into the obstacle, so instead of moving back it moves forward thus creating forced traction.  Which in effect sounds good and in hill climbs it helps a lot in keeping traction in the front.  If you are in a high traction enviornment, such as Moab where there is high traction smooth surfaces everywhere in climbs the front axle will actually pull the front of the vehicle down.  With the shackles in the rear with the same traction available, the front axle will want to move forward and actually raise the front of the vehicle up.  When you have front shackles and crossover steering (which is mandatory with front mounted shackles) the front axle will want to move side to side instead of turn the tires because the distance from the draglink to the shackle is too close.  A perfect example is a yj, find a buddy with a stock yj and take the trac bar off and take it for a drive, SCARY.  So really its up to you, it isnt imppossible by any means, you just have to decide if the trade offs are for you or not.

[Hyena]

Did we talk you out of it yet?  I have seen it done on only one toyota, and that was i na picture on pirate4x4.  Never seen it in person.

[toyhatsu]

dirtbag,

You really don't want Revolvers on the front as they will open up on you while trying to get over logs and other obstacles.  I have shackles on the front and it is a harsher ride as the natural tendancy for the spring is to push to the rear going over bumps and rocks while going forward.  With the shackle in the rear it is natural for the spring to absorb the shock better.  Also depending on the shackle length you loose some approach angle.  I have no idea what I am going to do with my front suspension but want to tackle it after the engine swap.  I know that it is wierd junk but listen to the real Toyota guys.

[toyhatsu]

side...look at those shackles sticking out

[dirtbag]

yeah i have heard the same thing. isnt that why jeeps have the shackle reversial kits?

that's the SHORT wheelbase rigs ( YJ's, CJ's ), not Wagoneers. I am seriously considering it, but, I can always change it if I don't like how it performs. I am experimenting. Thank you all for your input, I appreciate it. If I don't like it, I'll change it almost immediately.