What is better and WHY?

shackles behind is better ride.                     When the shackles are in the front when you hit a bump the springs and shackles want to move forward against the obstacle make for a hard jolt   when the shackles are behind the ride is smother do to the spring and shackle move back away from the obstacle

That's what I've always thought too. Anybody else wanna chime in?

Brent from trailtough, and people from lowrange said shackles in the front are better for wheeling. Reversal is better for road driving, but when you are wheeling and hit a rock the wheel moves back. Call Brent at trailtough and talk to them, they explain it better. He said never to do a reversal for wheeling.

IMO i have a shackle reversal from CALMINI and it does great for wheeling. i have never had any problems.

Mild to moderate wheeling and mostly DD the reverse is great. Serious offroading and mostly offroad I would go another way. There are other options too like rears up front and YJ springs ect.

was hoping for some fact,theory or physics on the subject. In my mind (that's not saying much) shackles in rear would always be better seems a person would not want his axle pushing in to a object he is trying to get on top of or over. I have had lots of different rigs with shackles both ways and have done reversals on a few. I liked the wheeling ability of the post reversal rigs better but that might have been a mental bias (just forked out the Benjamin's for it)

The reason shackle reversal is worse for extreme wheeling is the movement of the front axle during flex.  With a shackle reversal the axle pushes up and backwards moving closer to the transfer case, and when it flexes down it swings down and away from the t-case.   This requires the drive-shaft to have enough travel to compensate.   In a traditional configuration it pushes up and away then swings down and back, keeping close to the same distance from the t-case at all times so you require much less travel.

 

basically arnt all shackles bad for extreme off roading? wouldnt a 4-link be the way to go?

Obviously yes, the topic is shackles though.

Ok, here is a really basic pic to cover the issue.  One item to keep in mind is that a spring's length remains static, the point of a shackle is to allow the spring to flex upon impact.  When a spring flexes the axle will move forward or backwards based on the shackles location and the springs arch.  If your spring has a neutral arch the axle will move in a direction away from the shackle when it hits a bump, as the spring will go into negative arch.  If it has positive arch it will move in a direction towards the shackle when it hits a bump and the spring flattens.  Most shackle systems are designed for a positive arch to your spring with the axle in the middle of the spring.

In a shackle reversal the direction of travel for your axle when you hit a bump is up an towards your transfer case, and when flexing it is down and away from your transfer case.  So your drive shaft has to be able to retract and extend the entire distance and a long travel drive shaft may be required, otherwise when flexing out your drive shaft will fall apart during droop.

In the standard shackle forward configuration the direction of travel when the shackle is flexing keeps the axle close to the same distance from your transfer case.  Thus much less travel on your front drive shaft is needed for the same amount of flex.