Pro's/con's of longer shackles

[lovetoski]

Currently I have a heavy/heavy OME lift with their stock 3.5"/3.75" F/R shackels. I am thinking about going to the MAF 5" shackles. This would give me about 3/4" of lift (1/2 the difference in shackle length).

What other changes might I notice? Will the suspension flex differently - more flex, less flex? Will the truck track the same on the freeway?

In the searches I've done so far, the primary thing I've read is that longer shackles will tend to be more vertical, and this will make the suspension less compliant on smaller bumps...essentially harsher for on-pavement driving. Is this true?

Anything else that might be different?

Since pics are always good...

 

[Wile E Coyote]

Longer shackles up front will alter the caster angle with varying results.

Yes, shackle length plays an important part in overall suspension performance, as a shackle that's more-or-less 90 degrees will make an otherwise nice suspension ride like a covered wagon.

If the current shackle is long enough to allow the springs to already travel fully unencumbered, then a longer shackle will not add flex.
The amount of lift added is proportional to the shackle angle. The numbers you used to find lift (half the added shackle length) were determined using an assumed 45 deg shackle angle. The greater the shackle angle, the greater overall lift obtained. The opposite being also true.

 

[MANUCHAO]

I used to run that set up.
yes your ride will be more harsh.. with longer shackles.....
you might (i needed them) need caster shims.. 4° or 6° ....

 

[lovetoski]

Good points - thanks! My shackles are not at 45*, a little less really. So maybe more lift, but also more like a "covered wagon." LOL.

I already have 4* shims, drove like crap w/out them, probably only need 3*. Hmmm...gotta think more on this one.

 

[crushers]

i have run longer shackles (home made) for decades.
the ride was better since the flex is easier with longer shackles (common sense prevail)
the handling would suck till shims installed (caster is being changed)
you MIGHT need longer shocks since most kits supply shocks that are too short to begin with (a shock should never be the "droop" limiter)
if you are into rock crawling then longer shackles will become rock catchers.

i like the longer shackles

 

[Heckraiser]

Using longer shackles with the stock mounting points will make for a more vertical shackle angle (which is bad for flex and for ride comfort). However, if you chop off the shackle hangers and weld them back on an inch or two back, you'll get nice ride quality and a lot of droop which is swell. My ideal setup has limited uptravel (4-5") and as much droop as possible. I've seen mini trucks set up with 8" rear shackles that flex like the dickens.

I'd hesitate to go big on the front shackles because of the "smash it into a rock" factor.

 

[AlexJet]

Good info on shackle angle. Didn't think of this before.

 

[dcoy]

While on tbe general topic of shackles, would'nt a shackle reversal be a "better" way to go rather than a bigger shackle, giving a small amount of lift plus better suspension flex/articulation?

 

[Trapper50cal]

Problems are exposure and angle...as others have stated, if the stock hangers are used on the frame side, in the stock location, the longer the shackle, the more vertical the shackle angle will become. This will create the "covered wagon" ride quality. The longer the shackle up front, the more exposed it is to rocks and features of obstacles. I would also assume that since the shackles on the front are the leading connection to the leaf springs that the steering would begin to suffer as a result of perceivable "play" on the front of that which is holding the axle in place.

 

[AlexJet]

Longer shackle on the back shouldn't that bad, would it?

 

[Trapper50cal]

Longer shackle on the back shouldn't that bad, would it?

No, unless it gets to vertical. I used longer shackles (5.5" eye to eye) to get rid of some droop in the back. I made sure I got beefy, anti-inversion shackles just to be safe.

 

[AlexJet]

No, unless it gets to vertical. I used longer shackles (5.5" eye to eye) to get rid of some droop in the back. I made sure I got beefy, anti-inversion shackles just to be safe.

That's what I was thinking. To get some more clearance for 35s, to go with 6"-7" pin-to-pin in Tri-Shackle design, just debating to go with 1/4" steel plate or go further and use 3/8" or even 1/2" thickness???
By not being vertical, do you guys refer to level ground stand on the wheels or at full axle drop?

 

[Trapper50cal]

That's what I was thinking. To get some more clearance for 35s, to go with 6"-7" pin-to-pin in Tri-Shackle design...
By not being vertical, do you guys refer to level ground stand on the wheels or at full axle drop?

Lateral stability will be affected ( I would think ) the longer you go as well. 6 seems "okay" 7 is starting to sound "not okay"

 

[Slowerthanu]

While on tbe general topic of shackles, would'nt a shackle reversal be a "better" way to go rather than a bigger shackle, giving a small amount of lift plus better suspension flex/articulation?

Not necessarily, one of my rigs is reversed and one isn't. I notice no significant difference in handling or steering.

On the subject of longer shackles. You will alter geometry of suspension, reduce approach angle and gain minimal lift with a longer shackle.

The OME shackles are a nice compromise over a really long shackle.

 

[lehiguy]

I spent years and years monkeying around with shackle length and angle. (Had the internet been more available to me, I would have figured it out faster). The proper static angle is around 30 to 40 degrees inclined from vertical towards the fixed end of the spring. It has to be long enough to not invert in either direction. (I am of the opinion that if you need anti-inversion shackles, something is wrong with your geometry) The spring itself should be slightly lower in the rear (with relationship to the ground) than the front. On 60s with OME springs, moving the shackle mount inboard is required to obtain the proper static angle and accomodate a shackle of proper length to facilitate all possible articulation and not invert forwards or backwards. The ride is much, much better this way as well.

 

[Trapper50cal]

That's what I was thinking. To get some more clearance for 35s, to go with 6"-7" pin-to-pin in Tri-Shackle design, just debating to go with 1/4" steel plate or go further and use 3/8" or even 1/2" thickness???
By not being vertical, do you guys refer to level ground stand on the wheels or at full axle drop?

1/2" seems overkill but 1/4" or 3/8" seems okay. Too vertical of a shackle angle refers to level ground stance. You want the leaf spring side to be aft of the frame hanger side (on the back) and in front of the hanger side on the front.

 

[crushers]

when i used to make custom shackes i used 3/8" X 3" flat for the sides, very strong.
as long as the bushings are new then shackle float is not an issue.

 

[Clifton Bennett]

Will a shorter shackle kick out more than

a longer one? I don‘t need the lift, just looking for a softer ride. This sees too vertical.