After reading the post on front or rear shackles and seeing the responses I thought it was time to set the record straight.

A FRONT SHACKLE only causes the tires to move FOWARD on compression if the SPRINGS are ARCHED. On extention the tires will move REARWARD.

With a FRONT SHACKLE and FLAT SPRINGS the tire moves REARWARD on BOTH compression and extention.

A REAR SHACKLE with ARCHED SPRINGS causes the tires to move REARWARD on compression and FORWARD on extention.

BUT with a REAR SHACKLE and FLAT SPRINGS the tires to move FORWARD on BOTH compression and extention.

IT'S AS SIMPLE AS THAT...

BUT with a REAR SHACKLE and FLAT SPRINGS the tires to move FORWARD on BOTH compression and extention.

Yep, and thats why I have no problems with my tires moving into the fender wells... contrary to popular opinion mine arent cut flat for clearence.... its cause flopping it over made one a mangled mess ;) This is an obvious truth missed by a few. And if'n ya dont believe me.. at stuff my driveshaft is 3" longer than it is at rest.

you must have a whole lot-o-compression to even register a noticeable amount of forward movement with flat springs. lets just agree that tires move much less with flat springs.

Yeah, I abuse my poor flat springs. WAY into negative arch. Course thats going to change... and leave leafs behind for good.. and soon :D

Originally posted by RHINO
you must have a whole lot-o-compression to even register a noticeable amount of forward movement with flat springs. lets just agree that tires move much less with flat springs.

Agreed.

Flat springs are the way to go... more flex, better ride and less axle steer. :D

I think what we need to remember is that it depends on application. I'm going to rear shackles, but I'll probably move my axle forward a little to compensate. I have arched springs and the axle will move back, but I've alread hacked a bit at my inner fenderwell so it shouldn't be a problem. I see this whole shackle thing seems to be a big "jeep thing" problem:flipoff2:

No question about it. I was 4 inch SUA with shackle reversal, had all kinds of tires into the body problems. Went SOA, flat springs, no rubbing anymore, cuz now the tires move forward when compressing or extending.