It seems to me that SHORTER shackles would be the fix, rather than longer, if your springs seem short and you're at 90 degrees like that (before you invest in new springs or move the spring hangers). Yes, you end up with less shackle lift.
Shackle Angle
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Bad Coco
GOLD Star
I realize I am no master of these things, but it would make sense to me that if you have your shackle at 90* or inwards, the big problem would be as your suspension drops (ie. becomes shorter from bushing to bushing,) you quite likely would invert your spring.
Mark W
Yep, I really don't really care that much I guess.
Although Guppie makes an inference about even longer shackles (damn though, mine seem pretty long at 4 3/4" c2c when I look around)... the bigger question is (1) how would you fix this in my case without anything radical - a different style of shackle - and (2) how would it get this way on mine that is SUA as compared to another that is SUA and not running nearly 90 degree shackles?
THEORY: Also, I wonder if a static photo of a sitting still vehicles shackle angle really relates well to actual real world usage? That is, as it sits, it is an issue. But, as it moves: gravity & momentum take hold, the body moves and springs load and flex and weight is added with people and what not so when you actually drive and say come across a bump or hole or rut, since the rig is in movement (+ previously mentioned variables), you might be hitting that object at a time where the state of the vehicle relative to those shackles is no longer at 90 degrees in the real world so no harm no foul???
I think that theory is somewhat tenuous, but kind of makes sense in a way to me. BUT, I still see no harm in trying to make a change so mine are not 90 degrees, but not sure how without a radical change.
BTW, I was looking at SOR and saw this photo..
not much better angle than mine in their sales literature.... gives one the impression that if theirs is okay mine is okay..
Only way to change the shackle angle is to move the shackle hanger or to change the length of the spring. A different length shackle will affect things a small amount, buit not enough to mater in most cases.
Just because SOR or any other vendor shows something, doesn't mean it's a good thing.
With the same length of spring and the same length of shackle, a more steeply arched spring will have a steeper shackle angle. A spring like this will usually not droop as much as a flatter spring, and there is potential for great outward
movement of the shackle too.
Mark...
Mark W
Yep, I really don't really care that much I guess.
Not an issue in many setups, the shackle can limit uptravel if it is not long enough to let the spring flatten out. Not unheard of once you start putting not stock components together.
Mark...
maybe this is useful
http://www.bedfordspeedway.com/toolbox_leaf.htm
http://www.bedfordspeedway.com/toolbox_leaf.htm
Mark W
Yep, I really don't really care that much I guess.
This will usually reduce suspension flex, almost always increase the likelihood of shackle inversion and can sometimes increase the angle problem.
Mark...
OK, thanks! So much for intuition!
I *just* put the Downey cantilever shackles on the rear of my 40 yesterday.
HUGE improvement in ride quality!
My horrible Pinnacle's started riding a bit better after i plucked the bottom 2 leaves out. But not until they settled after wheeling. . . This gave me a better shackle angle but dropped my rear end 2" - 3".
I just put the Downeys on which gave me the 2" - 3" back and gave me a longer shackle and a much shallower angle. (Mine are closer to 45deg as opposed to the Downey pic above)
Rides like a new truck!
HUGE improvement in ride quality!
My horrible Pinnacle's started riding a bit better after i plucked the bottom 2 leaves out. But not until they settled after wheeling. . . This gave me a better shackle angle but dropped my rear end 2" - 3".
I just put the Downeys on which gave me the 2" - 3" back and gave me a longer shackle and a much shallower angle. (Mine are closer to 45deg as opposed to the Downey pic above)
Rides like a new truck!
OK, still puzzling over this shackle length thing. I realize it isn't real world, and there must be something wrong with my model. But, assuming a fixed spring length, and a fixed spring eye to shackle hanger length, I went from 65 degrees shackle angle with the longer shackle, to 55 degrees with the shorter shackle.
Isn't that an improvement? What am I missing in my assumption?
The only thing I can think of is that if the spring length is way too short (shorter than the spring eye to spring hanger length), then the shorter shackle exaggerates in the opposite direction as you pass 90 degrees.
Isn't that an improvement? What am I missing in my assumption?
The only thing I can think of is that if the spring length is way too short (shorter than the spring eye to spring hanger length), then the shorter shackle exaggerates in the opposite direction as you pass 90 degrees.
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Mark said *sometimes* increase the angle problem
big issue with shorter shackles is they don't let the spring flatten out as much when you hit a bump. I think generally, you'll get a better angle, but at a price.
big issue with shorter shackles is they don't let the spring flatten out as much when you hit a bump. I think generally, you'll get a better angle, but at a price.
Blue77FJ40
SILVER Star
I had the too short shackle problem with my HFS lift. The springs couldn't flex fully on compression and screeched loudly as they bent sideways. Until I put in longer shackles (about 1.5" over stock), I had to straighten out the springs after each outing as they kept moving sideways under the ubolts.
How will a longer shackle help out the angle? Seems to me like the angle will be the same unless you get a longer spring, or move the upper hanger towards the axel.
OK, I see that. The angle issue is only part of the story. And the effect of the length of the shackle depends on the relative lengths of the spring vs frame (spring eye to shackle hanger). A longer spring will show a bigger angle change with shackle length.
But I get the thing with a longer shackle giving the spring more lengthening with a bump. And starting out at 90 degrees is bad either way.
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The problem still becomes the length and arch of the spring. Longer shackles CAN help BUT you need something to help the springs flatten out a little (creating a longer e2e distance).
Add some weight, flex it out, repeat. The springs will soften/flatten and the shackle angle will improve! I posted my picture in post #18. The extra weight in the rear improved the ride 100 fold, the change was amazing!
Give it a try
One more thing: GOOD Soft-ride shocks can make a huge difference too
Add some weight, flex it out, repeat. The springs will soften/flatten and the shackle angle will improve! I posted my picture in post #18. The extra weight in the rear improved the ride 100 fold, the change was amazing!
Give it a try
One more thing: GOOD Soft-ride shocks can make a huge difference too
I *just* put the Downey cantilever shackles on the rear of my 40 yesterday.
HUGE improvement in ride quality!
My horrible Pinnacle's started riding a bit better after i plucked the bottom 2 leaves out. But not until they settled after wheeling. . . This gave me a better shackle angle but dropped my rear end 2" - 3".
I just put the Downeys on which gave me the 2" - 3" back and gave me a longer shackle and a much shallower angle. (Mine are closer to 45deg as opposed to the Downey pic above)
Rides like a new truck!
Where you get the Downey cantilever shackles from?
Thanks,
Thanks I will check them out.
Why does Downey say the cantilever shackles are only for 40s with Saginaw PS conversions? Thanks
so what is the downfall of an improperly angeled shackle? For example, mine are closer to 90 degrees (to the frame) - I assume it just adds to a harsh ride? and, how would you change just the angle? by changing the shackle out itself?
front
rear
Mine look like that, doesn't seem to affect the flex, but I always wondered why they won't angle out.
I would not think it would affect the 'flex' to much in those scenarios off road like you show. as the springs load, and push up and elongates, naturally the shackles would push out.
I think it would more affect the 'ride' and jolts when not in a situation where you are not really flexing the springs (like daily driving) much and actually calling on the shackles to roll out. in this situation, the 90 degrees is not taxed enough to roll out and allow the springs to activate much so instead it is transferred right into the body. if they were fortunately past 90 degrees (like those seen above) they would likely - even in daily driving scenario I mention with little taxing of the springs or shackle - allow to roll out as they are already slightly out (not at 90) so would work a little more.
