FSSR Questions - Mild Baja/Prerunner Setup

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Jeepin' Pete
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FSSR Questions - Mild Baja/Prerunner Setup

Postby Jeepin' Pete » Fri Apr 12, 2019 6:53 am

So I have a question about a front shackle reversal. I know that in a normal front spring setup a longer front shackle helps the spring articulate a little better, but longer than 1" makes the steering light. In a FSSR setup, how does a longer shackle change things?

I want to build my Wagoneer to do forest roads and desert roads well at (somewhat) higher speeds, and all the posts I can find on a baja / prerunner setup say that a FSSR is key, as the axle moves rearward. However, I want to keep the overall lift lower, so I'm thinking of doing Rocklaurence's FSSR and stock height Deaver springs, with maybe a longer shackle. Anyone have any suggestions on this?

And because the FSSR is still a spring under config, I'm assuming the lift gained by a longer shackle is 1/2 the added shackle height? (i.e. 1" longer shackle give 1/2" lift?)

Thanks guys!

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ross80truck
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby ross80truck » Fri Apr 12, 2019 8:33 am

So, this is by no means my expertise. So, I will state the following is opinion only. I am running the Rocklaurence kit on my Cherokee Chief. I do not notice any difference in steering feel. This is with a stock shackle. It gave me roughly a 2" lift. When I went to get it aligned, my caster was off. They had to rock the axle back another 1.5" degrees with shims to get it where they wanted it. My alignment guy is a good friend and a perfectionist. I would like a little more lift. I am thinking about running a 1" longer shackle on the front leaf spring. This most likely will allow me to remove the shim and give me that 1" lift.

Also, I would highly recommend talking to the guys at Off Road Design. They specialize in square body Chevy trucks and those trucks are very similar to ours. Any info they give you on the prerunner setup will work on our rigs.
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Jeepin' Pete
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby Jeepin' Pete » Fri Apr 12, 2019 9:11 am

ross80truck wrote:So, this is by no means my expertise. So, I will state the following is opinion only. I am running the Rocklaurence kit on my Cherokee Chief. I do not notice any difference in steering feel. This is with a stock shackle. It gave me roughly a 2" lift. When I went to get it aligned, my caster was off. They had to rock the axle back another 1.5" degrees with shims to get it where they wanted it. My alignment guy is a good friend and a perfectionist. I would like a little more lift. I am thinking about running a 1" longer shackle on the front leaf spring. This most likely will allow me to remove the shim and give me that 1" lift.

Also, I would highly recommend talking to the guys at Off Road Design. They specialize in square body Chevy trucks and those trucks are very similar to ours. Any info they give you on the prerunner setup will work on our rigs.


Thank you! The way I understand it is that the FSSR is pretty good with stock springs, but with any lift springs it gets pretty complicated to do correctly. (double-cardan long-travel slip driveshaft, possible cut-and-turn on the C's needed to keep proper caster...) Because my rig is not actually going to be a race truck, I'm not really sure if it is worth it. The new lift kits from BJ's are made by Deaver and have 9 leaves up front, so the ride is probably pretty good with the stock setup.

When I envision it in my head, the longer rear shackle actually makes things worse in regards to driveshaft angle. Also, the centering pin on the springs of our FSJ's are 1 inch offset, so the reversal further screws up the OEM geometry.

RamJetFSJ
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby RamJetFSJ » Fri Apr 12, 2019 9:54 am

I would talk to the guys at T and J Performance in Orange, CA. They have a beefier FSSR setup, and have built and raced leaf sprung FSJs off road. (But beware their website, its sometimes comes up as being hacked). But I think with a relatively flat leaf pack, I don't think the longer shackle will make much of a difference in articulation. Its comes into play more with a spring pack with more arch. As long as the shackle angle is right that is. Sometimes a longer shackle can fix an incorrect shackle angle.

A FSSR setup will be much smoother in the desert for sure though. If you do Rock Laurences kit, be sure to weld it in addition to bolting it on. And beef it up a little with some gussets if your going to do some heavy off roading.

I tried longer shackles, and just couldn't make them work. Part of that is the lack of a track bar on my '80. (Standard shackle front setup). Went back to stock shackles... too much steering wander.

You are correct, lift from a shackle is MAX 1/2 the shackle length (depending on shackle angle).
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Jeepin' Pete
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby Jeepin' Pete » Fri Apr 12, 2019 11:17 am

RamJetFSJ wrote:I would talk to the guys at T and J Performance in Orange, CA. They have a beefier FSSR setup, and have built and raced leaf sprung FSJs off road. (But beware their website, its sometimes comes up as being hacked). But I think with a relatively flat leaf pack, I don't think the longer shackle will make much of a difference in articulation. Its comes into play more with a spring pack with more arch. As long as the shackle angle is right that is. Sometimes a longer shackle can fix an incorrect shackle angle.

A FSSR setup will be much smoother in the desert for sure though. If you do Rock Laurences kit, be sure to weld it in addition to bolting it on. And beef it up a little with some gussets if your going to do some heavy off roading.

I tried longer shackles, and just couldn't make them work. Part of that is the lack of a track bar on my '80. (Standard shackle front setup). Went back to stock shackles... too much steering wander.

You are correct, lift from a shackle is MAX 1/2 the shackle length (depending on shackle angle).


I'll try and get in touch with them. I worked with their website a little, but at times it seem hacked, and then when it did come up it was dated and pretty hard to navigate.

I ask because I'm torn between stock springs with an FSSR, and 2" springs with the FSSR setup. Sounds like the shackle length would be more critical with the 2" leafs as they are more arched.

Jeepin' Pete
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby Jeepin' Pete » Fri Apr 12, 2019 2:07 pm

I understand that the driveshaft needs to be changed because the axle now moves rearward and the OEM driveshaft does not have enough slip, thus pushing it through the transfer case. However, I'm still confused about the change in pinion angle.
Because the centering pin is offset, couldn't you turn the spring around so the pinion rotates toward the TC upon compression rather than away from it?
The following (crude) drawing is what I'm picturing: (the black dot on the leaf spring is the centering pin)

Leaf Spring Offset Diagram.jpg


If the centering pin is offset towards the front, the pinion will rotate up toward the TC upon compression. Likewise, if the centering pin is offset toward the rear, upon compression the pinion would rotate down away from the TC, all based on the arc of the spring and how it changes during compression. Is this correct?

I also sent T and J performance an email, I'll post up if they say anything.

For reference the following article has some pretty good photos of a front spring shackle reversal. I can't quite tell if there are shims under the axle to correct any angles.

http://www.fourwheeler.com/project-vehi ... okee-race/
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rocklaurence
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby rocklaurence » Sat Apr 13, 2019 9:00 am

If your looking for a High Peromance pre-runner setup, you may want to wait for my new Long Spring front susension system. Starting with the FSSR, with new replacement rear shackle brackets, 52" springs and new Shock/Bump stop brackets provide 12" of wheel travel and 5" of lift. Im currently running it on my J20 and it works great. I'm currently working on a rear suspension setup to complement the front. Just saying, It most likely will be less expensive that a SkyJacker or custom Deaver setup.

Jeepin' Pete
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby Jeepin' Pete » Sat Apr 13, 2019 12:52 pm

rocklaurence wrote:If your looking for a High Peromance pre-runner setup, you may want to wait for my new Long Spring front susension system. Starting with the FSSR, with new replacement rear shackle brackets, 52" springs and new Shock/Bump stop brackets provide 12" of wheel travel and 5" of lift. Im currently running it on my J20 and it works great. I'm currently working on a rear suspension setup to complement the front. Just saying, It most likely will be less expensive that a SkyJacker or custom Deaver setup.


I was hoping you would chime in! I’d seen mention of that new system and am definitely curious! Because it’s using the FSSR and arched springs I’m assuming a longer slip driveshaft is needed?

I was planning on doing the Ford shock mounts and Timbren active off-road bumpstops ( the ones for the rear of the Xterra will fit). Any available details on your shock mounts and bumpstops?
Also any details on ETA? Will you sell the front separate?
I bought your NP229 twin stick kit (haven’t installed it yet) so I’m really interested in this!

The Deavers wouldn’t be custom, just the pack from BJ’s, but I’m always interested in the details of a different system.


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rocklaurence
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby rocklaurence » Mon Apr 15, 2019 6:52 am

"I was hoping you would chime in! I’d seen mention of that new system and am definitely curious! Because it’s using the FSSR and arched springs I’m assuming a longer slip driveshaft is needed?

I was planning on doing the Ford shock mounts and Timbren active off-road bumpstops ( the ones for the rear of the Xterra will fit). Any available details on your shock mounts and bumpstops?
Also any details on ETA? Will you sell the front separate?
I bought your NP229 twin stick kit (haven’t installed it yet) so I’m really interested in this!

The Deavers wouldn’t be custom, just the pack from BJ’s, but I’m always interested in the details of a different system."

Hi, it is a process to put these things together. The biggest delay has been getting the brackets cut for me because I'm a small customer that the Fab' Shop has to work-in between real jobs. ;) I'm running the proto-type brackets now with the shocks, bump stops, modified swaybar links to ensure that its a reliable-sustainable system. Soon, I'm going to switch over from the current Hydro shocks to adjustable Ranchos and see how much better they are-if at all better. I will provide the option to buy a Front Suspension and a Front/Rear suspension--what ever the customer wants. However, I do have a question for everyone on the board. Would most of you prefer the Long Travel front drive shaft with the kit or would you rather purchase it on your own? The Drive shaft will likely cost more than $400.

Jeepin' Pete
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby Jeepin' Pete » Mon Apr 15, 2019 7:30 am

rocklaurence wrote:However, I do have a question for everyone on the board. Would most of you prefer the Long Travel front drive shaft with the kit or would you rather purchase it on your own? The Drive shaft will likely cost more than $400.


I would say probably purchase it on my own. That way the cost of the kit can be spread out over time. The Jeep can be run in 2wd while the kit is installed, giving the customer the time to recoup funds and then purchase the driveshaft. It would be very helpful to have the driveshaft measurements available at the time of purchase. My 2 cents...

Jeepin' Pete
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby Jeepin' Pete » Mon Apr 15, 2019 10:59 am

RockLaurence, when you run your FSSR kit, do you run stock springs? Do you have any experience with longer shackles?

rocklaurence
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Re: FSSR Questions - Mild Baja/Prerunner Setup

Postby rocklaurence » Wed Apr 17, 2019 4:09 pm

Jeepin' Pete wrote:RockLaurence, when you run your FSSR kit, do you run stock springs? Do you have any experience with longer shackles?

Yes, many use the OEM springs. Weather you'll need longer shocks or front drive shaft is dependant on the condition of the springs. For example: many old springs are sagging which doesnt require longer shocks or drive shaft because it only adds an inch or two +- over the original hieght.


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