Shackles, brackets and relocation
#1
Senior Member
Thread Starter
Shackles, brackets and relocation
The Stock XJ leafs are comparatively "flat" in shape compared to aftermarket lift leafs that have a greater arch. And the stock shackle looks to be about ~4" ?
The leaf absorbs shock by "straightening " or flattening. The front of the leaf is firmly attached to the body, so as the spring flattens the rear of the spring moves back, and the shackle swinging back allows this.
The more arch the spring initially has, the more the rear eye needs to swing back. A stock, almost flat leaf doesn't move much so the short stock shackle is fine.
with an aftermarket leaf with more arch, the rear of the spring move back much more, and I would think the stock (short) shackle is going to limit this, making the leaf "bottom out" sooner than it should?
So that brings me to a few questions:
1) Why do people want a 45deg shackle position at rest? you are already giving away 1/2 the travel of the shackle,, would not 90deg (straight down) give you the most travel?
2) is not it more important to have a Longer shackle with aftermarket springs, so you have more travel before the spring is limited by the shackle swinging straight back?
3) do leaf spring manufactures state a min shackle length?
4) most shackle mount relocation brackets drop the mounting holes down 3-4" from stock,, plus using a longer aftermarket shackle, doenst this lift the rear a few inches?
Let me know where I am going wrong here?
Getting ready to address the rear suspension and mounts, while I have the rear all opened up (rear floor pan removed) and welding in there.
Slack
The leaf absorbs shock by "straightening " or flattening. The front of the leaf is firmly attached to the body, so as the spring flattens the rear of the spring moves back, and the shackle swinging back allows this.
The more arch the spring initially has, the more the rear eye needs to swing back. A stock, almost flat leaf doesn't move much so the short stock shackle is fine.
with an aftermarket leaf with more arch, the rear of the spring move back much more, and I would think the stock (short) shackle is going to limit this, making the leaf "bottom out" sooner than it should?
So that brings me to a few questions:
1) Why do people want a 45deg shackle position at rest? you are already giving away 1/2 the travel of the shackle,, would not 90deg (straight down) give you the most travel?
2) is not it more important to have a Longer shackle with aftermarket springs, so you have more travel before the spring is limited by the shackle swinging straight back?
3) do leaf spring manufactures state a min shackle length?
4) most shackle mount relocation brackets drop the mounting holes down 3-4" from stock,, plus using a longer aftermarket shackle, doenst this lift the rear a few inches?
Let me know where I am going wrong here?
Getting ready to address the rear suspension and mounts, while I have the rear all opened up (rear floor pan removed) and welding in there.
Slack
#2
Senior Member
Thread Starter
OK, question on after market relocation brackets:
I see the are typ 1/4" thick material, does that "flex" enough that when you tighten down on the shackle bolt it "squeezes" the shackle bushing and holds it?
or is the shackle bushing inner sleave just rotating on the shackle bolt? creating wear of the bolt and inner sleave?
Slack
I see the are typ 1/4" thick material, does that "flex" enough that when you tighten down on the shackle bolt it "squeezes" the shackle bushing and holds it?
or is the shackle bushing inner sleave just rotating on the shackle bolt? creating wear of the bolt and inner sleave?
Slack
#3
Senior Member
Join Date: Jul 2015
Location: Southern Maryland
Posts: 563
Likes: 0
Received 2 Likes
on
1 Post
Year: 1993
Engine: 4.0
1) having a static angle of 90 would give you the most potential uptravel, however it completely removes opportunity for down travel except for decompression of the leaf. Also at 90 you have maximum force transfer into the vehicle, at 45 the force is evenly distributed up and back
2)A longer shackle does allow for more travel
3)I don't know for sure, the spring will behave more optimally with a longer shackle but it will still work with a short one. There probably is a sweet spot but I doubt most manufacturers really put in the R&D to figure it out, maybe look at Jeepspeed style rigs and copy what they do.
4) yes it does raise the rear, sort of, if you have a 90 degree shackle, kicking it back to 45 degrees makes it's effective overall length in the "y" plane shorter, we'll call this "S", equal to S*cos45, for example a 6 inch shackle at 90 degrees is only 4.24" tall sitting at 45, so while the bracket drops the hole a few inches, the difference in shackle angle could compensate (might want to double check my trig, but concept is legit). Also since you have your rear opened up, check out the no lift relocation brackets by HD offroad engineerning, this way you can use a longer shackle to optimize travel, without getting too much lift.
5)the brackets I have (HD offroad standard) did not have this as an issue. 1/4" steel will flex enough, but in my case it was a very tight fit to begin with.
2)A longer shackle does allow for more travel
3)I don't know for sure, the spring will behave more optimally with a longer shackle but it will still work with a short one. There probably is a sweet spot but I doubt most manufacturers really put in the R&D to figure it out, maybe look at Jeepspeed style rigs and copy what they do.
4) yes it does raise the rear, sort of, if you have a 90 degree shackle, kicking it back to 45 degrees makes it's effective overall length in the "y" plane shorter, we'll call this "S", equal to S*cos45, for example a 6 inch shackle at 90 degrees is only 4.24" tall sitting at 45, so while the bracket drops the hole a few inches, the difference in shackle angle could compensate (might want to double check my trig, but concept is legit). Also since you have your rear opened up, check out the no lift relocation brackets by HD offroad engineerning, this way you can use a longer shackle to optimize travel, without getting too much lift.
5)the brackets I have (HD offroad standard) did not have this as an issue. 1/4" steel will flex enough, but in my case it was a very tight fit to begin with.
#4
Seasoned Member
Join Date: Nov 2012
Location: Fort Collins, Colorado
Posts: 327
Likes: 0
Received 4 Likes
on
3 Posts
Year: 1998 (buggy), 1998 DD
Model: Cherokee
The Stock XJ leafs are comparatively "flat" in shape compared to aftermarket lift leafs that have a greater arch. And the stock shackle looks to be about ~4" ?
The leaf absorbs shock by "straightening " or flattening. The front of the leaf is firmly attached to the body, so as the spring flattens the rear of the spring moves back, and the shackle swinging back allows this.
The more arch the spring initially has, the more the rear eye needs to swing back. A stock, almost flat leaf doesn't move much so the short stock shackle is fine.
with an aftermarket leaf with more arch, the rear of the spring move back much more, and I would think the stock (short) shackle is going to limit this, making the leaf "bottom out" sooner than it should?
So that brings me to a few questions:
1) Why do people want a 45deg shackle position at rest? you are already giving away 1/2 the travel of the shackle,, would not 90deg (straight down) give you the most travel?
2) is not it more important to have a Longer shackle with aftermarket springs, so you have more travel before the spring is limited by the shackle swinging straight back?
3) do leaf spring manufactures state a min shackle length?
4) most shackle mount relocation brackets drop the mounting holes down 3-4" from stock,, plus using a longer aftermarket shackle, doenst this lift the rear a few inches?
Let me know where I am going wrong here?
Getting ready to address the rear suspension and mounts, while I have the rear all opened up (rear floor pan removed) and welding in there.
Slack
The leaf absorbs shock by "straightening " or flattening. The front of the leaf is firmly attached to the body, so as the spring flattens the rear of the spring moves back, and the shackle swinging back allows this.
The more arch the spring initially has, the more the rear eye needs to swing back. A stock, almost flat leaf doesn't move much so the short stock shackle is fine.
with an aftermarket leaf with more arch, the rear of the spring move back much more, and I would think the stock (short) shackle is going to limit this, making the leaf "bottom out" sooner than it should?
So that brings me to a few questions:
1) Why do people want a 45deg shackle position at rest? you are already giving away 1/2 the travel of the shackle,, would not 90deg (straight down) give you the most travel?
2) is not it more important to have a Longer shackle with aftermarket springs, so you have more travel before the spring is limited by the shackle swinging straight back?
3) do leaf spring manufactures state a min shackle length?
4) most shackle mount relocation brackets drop the mounting holes down 3-4" from stock,, plus using a longer aftermarket shackle, doenst this lift the rear a few inches?
Let me know where I am going wrong here?
Getting ready to address the rear suspension and mounts, while I have the rear all opened up (rear floor pan removed) and welding in there.
Slack
2.) No, it is not.
3.) No, they do not, there is no reason for them to.
4.) Depending on length of shackle and angle yes and no.
#5
Senior Member
Thread Starter
Thanks for the response,, I have read more about leafs, shackles and relocation brackets in the last 48 hous than I care to admit.
Cut and ground off the stock shackle mounts and picked up a bunch of flat steel to fab up new multi position weld in brackets.
Slack
Cut and ground off the stock shackle mounts and picked up a bunch of flat steel to fab up new multi position weld in brackets.
Slack
Thread
Thread Starter
Forum
Replies
Last Post
HS00XJ
Modified XJ Cherokee Tech
4
01-20-2015 11:34 AM
dukie564
Modified XJ Cherokee Tech
23
06-11-2012 08:03 AM
DIRTDOGXJ
Cherokee Chat
7
02-24-2012 03:39 PM
huntingman2706217
For sale
14
08-15-2010 10:42 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)