drop shackle questions

Parker_

Parker_

I'm a torque addict !!
May 13, 2014
244
1
18
Blythe ca
I have the same shackles and I know a few people including myself that run the bolts opposite of factory . No issues


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baddaddition

baddaddition

New member
Mar 10, 2013
287
0
0
Pm flyin Elvis his truck we did two yrs. Ago and sets really nice!

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flyinelvis11

flyinelvis11

Member
May 11, 2010
543
0
16
50
VG, IL (because my wife does)
Late to the party as usual.....lol
As you well know the only way to make these gold trucks look good is to mod the crap out of them.... 3" rear drop and keys turned way out
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063346400daf59a1920eda7a67a3d748.jpg


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Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,759
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Phoenix Az
A little info for those that dont know how to figure out how much the shackle will lower their truck when it has multiple holes.

If you want the shackle to lower the back of the truck 1", it will take a 2" longer shackle than stock to achieve it. Think of the springs as a lever with the fulcrum point at the front where the spring bolts to the frame hanger. the axle is exactly half way back from that fulcrum point while the shackle is at the very end. to move the axle any amount, the shackle must move twice as much.

so to get 3" of drop, it will take a 6" longer shackle than stock. I can say ive seen a few drop shackles that dont measure out to what they claim and you can see it in the drop they give. specifically the "1-2 drop shackles" i have on my truck. measured them out and at the top hole, i showed i should only get 1" of drop and no more. put them on where i measured and they were exactly that. granted these were the cheapest ones i could find on ebay so im not surprised.
 
melms23

melms23

Member
Jul 30, 2011
253
0
16
WI
I agree. My eBay 3" shackles achieved a 2" drop. Even with the shackles and overload removed, the truck is not low in the rear by any means.

Still has a good amount of rake with the t-bar bolts removed.
 
fastpunker

fastpunker

adrenaline junkie
Feb 7, 2012
215
1
16
Lake Havasu City, AZ
Chevy1925 said:
A little info for those that dont know how to figure out how much the shackle will lower their truck when it has multiple holes.

If you want the shackle to lower the back of the truck 1", it will take a 2" longer shackle than stock to achieve it. Think of the springs as a lever with the fulcrum point at the front where the spring bolts to the frame hanger. the axle is exactly half way back from that fulcrum point while the shackle is at the very end. to move the axle any amount, the shackle must move twice as much.

so to get 3" of drop, it will take a 6" longer shackle than stock. I can say ive seen a few drop shackles that dont measure out to what they claim and you can see it in the drop they give. specifically the "1-2 drop shackles" i have on my truck. measured them out and at the top hole, i showed i should only get 1" of drop and no more. put them on where i measured and they were exactly that. granted these were the cheapest ones i could find on ebay so im not surprised.
Click to expand...

Glad you hit on that James, I'm a little surprised nobody else chimed in on that also. Are our rear leafs a 50/50 ratio for the axle pin? (I can't remember atm, I know my Tacoma factory leafs are more of a 40/60 ratio)
 
c20elephant

c20elephant

C20ELEPHANT
Apr 25, 2013
2,065
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0
Phoenix, Arizona
As you lower via shackles the pinion is also pointed downward the further you drop. Depending on your truck you may or not acquire a driveline vibration.
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,759
5,933
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Phoenix Az
fastpunker said:
Glad you hit on that James, I'm a little surprised nobody else chimed in on that also. Are our rear leafs a 50/50 ratio for the axle pin? (I can't remember atm, I know my Tacoma factory leafs are more of a 40/60 ratio)
Click to expand...

yup, ours are 50/50. toyota and jeep did weird 70/30, 60/40 ratios on some rigs. XJs use a really off set pin
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
c20elephant said:
Not based on the front being the fulcrum, draw a picture of the leaf spring and strike a line though the leaf spring ends and raise the rear one it points the pinion downward
Click to expand...

your right, im thinking of lifting it.

i have usually suggested people grab a pair of 3* shims for the rear end when they use a 3" drop shackle. more than 3" of drop starts to get into a very long shackle (ass end can become unstable) and very bad pinion angle
 
c20elephant

c20elephant

C20ELEPHANT
Apr 25, 2013
2,065
0
0
Phoenix, Arizona
I had a thought you might be getting high, oh wait, lifting it...:rofl:

Now for the other part of the drop, the thickest part of the shim is to the back to adjust the pinion back up, I believe that is correct...
 
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motoking_1990

motoking_1990

Active member
May 9, 2011
1,957
5
38
Terre Haute, IN
Chevy1925 said:
your right, im thinking of lifting it.

i have usually suggested people grab a pair of 3* shims for the rear end when they use a 3" drop shackle. more than 3" of drop starts to get into a very long shackle (ass end can become unstable) and very bad pinion angle
Click to expand...

c20elephant said:
I had a thought you might be getting high, oh wait, lifting it...:rofl:

Now for the other part of the drop, the thickest part of the shim is to the back to adjust the pinion back up, I believe that is correct...
Click to expand...
What are these shims you speak of?

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Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,759
5,933
113
Phoenix Az
^^ yes but be careful. Some of these shims don't come with a pin in them to keep the leaf pack centered. You may need to put a longer center pin in with a spacer between it and the leaf pack so the pin can sit in the hole of the axle
 
danzick

danzick

playing with fire
Feb 20, 2014
576
16
18
Livingston, MT
Chevy1925 said:
A little info for those that dont know how to figure out how much the shackle will lower their truck when it has multiple holes.

If you want the shackle to lower the back of the truck 1", it will take a 2" longer shackle than stock to achieve it. Think of the springs as a lever with the fulcrum point at the front where the spring bolts to the frame hanger. the axle is exactly half way back from that fulcrum point while the shackle is at the very end. to move the axle any amount, the shackle must move twice as much.

so to get 3" of drop, it will take a 6" longer shackle than stock. I can say ive seen a few drop shackles that dont measure out to what they claim and you can see it in the drop they give. specifically the "1-2 drop shackles" i have on my truck. measured them out and at the top hole, i showed i should only get 1" of drop and no more. put them on where i measured and they were exactly that. granted these were the cheapest ones i could find on ebay so im not surprised.
Click to expand...

thanks for the good info. Thats what I was wondering in the first place. I've atually come to be pretty happy with how it sits. I measured a buddies stock truck and his space from tire to wheel well was 10 inches and mine is 8 so im happy. It looks taller in the picture.
 
motoking_1990

motoking_1990

Active member
May 9, 2011
1,957
5
38
Terre Haute, IN
Chevy1925 said:
^^ yes but be careful. Some of these shims don't come with a pin in them to keep the leaf pack centered. You may need to put a longer center pin in with a spacer between it and the leaf pack so the pin can sit in the hole of the axle
Click to expand...
So the shims is thicker on one end to tilt the axle one way or another? Interesting. I'm new to this whole lowering thing. The question is how much angle is too much and causes problems?

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Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,759
5,933
113
Phoenix Az
motoking_1990 said:
So the shims is thicker on one end to tilt the axle one way or another? Interesting. I'm new to this whole lowering thing. The question is how much angle is too much and causes problems?

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Click to expand...


It's quite a bit of text for me to put up again but the short of it is, you want the downward angle of the tcase output or Trans output to be the same as the upward angle of the pinion. You want to be within a few degrees of either. Then you select your shim and install
 
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