I have an early 86 f250 (build date 08/85) that I'm wanting to put a front shackle reversal on.

I see that ORU makes a kit for 86.5 -91. Any one know what difference may be between 86 and 85 front frames or horns?

I was under impression they r all the same.

Thanks

 

Can't answer the frame question but to run RSK you will need a solid axle under your truck if you havent swapped one in already.

I am sure it would fit and may only need minor modification, have you tried calling ORU?

 

Yeah I have a solid axle for it.

And oru wasn't much help, they just said it's not made for it and he doesn't know what they may have changed.

 

measure the springs. some were 2.5", and some were 3"

 

Mine are 3".

 

yours is the newer truck

 

If I'm remembering correctly, guys run these by boxing in the front frame horns.

 

You can use it. Go to the 4x4 offroad forum and post this question there they have a write up on what's necessary.

 

I am sure their listing refers to stock f350's, since they were the only ones from the factory that came with a straight axle. And guess what? They only started putting the straight axle into the f350's starting around 1986. So I believe that's what the difference is.

I sure would like to pick the brain of the engineer who designed the frontend on these trucks. You know when they were on the design board, they could have put the shackle on the rear or on the front, and they must have had a reason to put it on the front.

 

The reason it's on the front is to keep the shackle from unloading during hard braking, such as a panic stop.
Many vehicles with front leafs use this design (like Jeep CJs).
Pardon my crude drawing:


If you can get past the Jeep part, here's some good info for those who need it or are just curious:
Pros and Cons of Shackle Reversal

 

The only reason it was put on the front is for the TTB , the rear solid mount helps hold every thing in a straight line !
and then when they put the solid axle in they kept it the same to save money as to not re engineer it !

 

Well, Jeeps didn't have a ttb and they have the shackle in the front!

My 56 Ford f100 with a straight axle and leaf springs in the front had the shackle in the front also!

I am going to read that link, it seems like a reasonable explanation why they did it!

I am also not sold on the shackle flip kits on the rear either! That puts the shackle in compression instead of tension! A steel support is much stronger in tension than compression!

I am trying your ! exclamation thing, and it's much easier just to hit the period button.

 

Like Franklin mentioned, the only flaw in this statement is that Ford was using front shackles on their straight axles and military "jeeps" long before the TTB was a speckle of a thought in an engineers mind.

 

You can ONLY use the RSK if using a D60.

There is NO DIFFERENCE from 80-91 on the 4wd F250/F250 frame horns. But if you can do some MILD fabercation. you can save about $125 by buying SKY manufacturing's RSK and just supply some metal to box the frame. 92-97 F-250/F-350 front shackle reversal - Sky's Off-road Design They only list one for 92-97 but are the same thing, you just need to box the frame where it bolts in. ORUs is the same thing but they give you the material to box the frame on the 80-91 trucks

 

Franklin, people use the rear shackle flip for a) easy couple inches of lift and b) to increase stability in their off road vehicle. I went back to the drawing board to help better explain (again sorry for the crude drawings, but I hope they give some visual help):

Factory vs Shackle Flip



Now the factory rear shackle set-up is meant to increase load carrying capacity, that's it. As a factory shackle is loaded it swings towards the rear of the vehicle and if loaded far enough, will rest on top of the shackle bracket. With the shackle flip, the shackle will also swing back, but there's nothing underneath it to add additional support, which reduces your load carrying capacity.

The factory set-up is good if you're concerned with carrying heavy loads, not so much if you want your suspension to flex.

Imagine your rear axle climbing over an obstacle:

As the tire is going up the obstacle, the shackle on that side wants to swing back and the other shackle wants to swing forward. With a shackle flip, you allow the shackle a greater range of motion before binding. With the factory set-up, the bracket is the point of binding. Once the shackle contacts the shackle hanger, it has no where else to go, and so the frame of the vehicle has to twist to compensate. The problem is, when your frame is twisting, you have less stability.




Notice that this XJ is dead nuts level and only the suspension is flexing, not the vehicle.


In this picture you can see the position of the rear shackle.

Hope that gives you a better idea of why guys flip their shackles.

Sorry for the thread hijack OP...