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Suspension upgrade recomendations

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north796 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote north796 Quote  Post ReplyReply Direct Link To This Post Topic: Suspension upgrade recomendations
    Posted: 25 Jan. 2022 at 8:23pm
Since so many people have messing with these jeeps for so long, Im looking for suspension recommendations. Im building a frame, and I do not care about stock ( sorry to the purists). If anyone can help I would appreciate it. I'm keeping some type of leaf spring and the original dana 25 and 41. Im looking for comfortable (as possible) off road characteristics.....cushy suspension, yea i know u can only go so far. I could use ideas like longer shocks? longer springs? Im probably adding hydraulic bump stops. I might add an inch or 2 of lift, but i want to keep it lower and smaller, no huge tires. I'm rebuilding the l head. Thanks!  
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wfopete View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wfopete Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2022 at 8:28pm
Just a thought, if you have springs already you may want to try removing a couple of the shorter leaf's to soften things up.  
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oldtime View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2022 at 8:58pm
Building a frame ? But using standard axles. Seems kinda strange.
In any case I suggest you stay with stock type leaf springs and soft action shock absorbers; Not heavy duty Rancho shocks.
You might consider installing rear springs (42” long) at both front and rear.
But using any longer springs on a flatfender gains little advantage and increases your shock travel and possibly some propeller shaft issues.
You sure don’t need a lift to get a soft ride.
If you want a soft ride then take a standard spring pack and reduce it to 7 leaves evenly spaced.
Also consider front shackle reversal, but here you will certainly get into propeller shaft changes.
This will give a much softer ride off -road.
Here you basically want to mimic the M38-A1 design.
I don’t recommend front shackle reversal for on road operation due to nose dive braking with soft leafs.


Edited by oldtime - 25 Jan. 2022 at 9:05pm
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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Mark W. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2022 at 9:10pm
CJ5 Springs front and rear I have them on my cj2a frame and my ride is very nice. I'm using NAPA shocks and 1" lift shackles. With a 28" tall tire my door opening sits at 29" which is about all I can swing my foot over.

Edited by Mark W. - 25 Jan. 2022 at 9:12pm
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oldtime View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2022 at 9:15pm
Mark, did you go to a longer than standard shock length. 
Or did you limit your spring travel via the standard shock ?
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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Noah View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Noah Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2022 at 9:27pm
How long are CJ5 springs compared to stock willys springs?

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oldtime View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2022 at 9:39pm
Flatfender front 36-1/4”
Flatfender rear 42”
Flatfender shock length front and rear 10-3/4 compressed to 17-1/2” extended

M38A1-CJ-5 front 39-5/8”
M38A1-CJ-5 rear 46-1/8”
M38A1-CJ-5 Shock length Front 11-7/16” compressed to 18-7/16” extended Rear 11-15/16” compressed to 19-7/16” extended.




Edited by oldtime - 25 Jan. 2022 at 9:44pm
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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Noah View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Noah Quote  Post ReplyReply Direct Link To This Post Posted: 25 Jan. 2022 at 10:11pm
Thanks oldtime,

also are M38-A1 and early CJ-5 springs the same width as flat fender springs?


Edited by Noah - 25 Jan. 2022 at 10:12pm
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oldtime View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jan. 2022 at 10:47am
Yes all pre 1976 CJ springs are 1-3/4” wide.

The 46-1/8” long spring began in 1953 with the A1.
This change required a frame redesign. 
In order to fit longer springs to a flatfender you “must” somehow extend all the frame horns. 
Most notably the front horns if you are going from standard 36-1/4” to 46-1/8”.
This change obviously can effect the standard 80” flatfender wheelbase.

That’s basically why I don’t recommend going to 46-1/8” springs.
A lot of extra changes for relatively small change in ride quality.
If strictly used off road a front shackle reversal would provide more notable improvement.

Myself I am running standard flatfender springs at both front and rear. Several reasons.
1) Jeep value is unaffected
2) easier to source springs if all remains standard
3) engine selection should be a priority over suspension.
My last two flatfender builds have Dauntless 225 and this limits the front suspension travel. In other words the standard front stuff and droop is right at it’s limit without incurring front propeller shaft interference.



Edited by oldtime - 26 Jan. 2022 at 10:49am
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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oldtime View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jan. 2022 at 12:44pm
Another thing to consider is that changing to longer leafs will soften the ride some but it will not add suspension travel unless you re-arrange and or change the shock absorbers.
Laying the shocks down diagonal to the direction of axle travel will increase the travel distance and decrease the shocks damping effect.
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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smfulle View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote smfulle Quote  Post ReplyReply Direct Link To This Post Posted: 26 Jan. 2022 at 1:49pm
I hesitate to comment of suspension stuff these days. Most people think I'm just silly anyway. But..

My limited experience has lead me to believe the stock replacement springs give the best compromise of soft ride and off road performance. Newer lift springs, even custom ones, seem to always be stiffer. So you can get a bigger tire under there, but it's harder to keep that tire on the ground due to limited flexibility. 
Some of the vendors have very nice, US made replacement springs (Walcks), but they tend to be heavier duty with more leaves. Great for shows, or even heavy ranch work, but not so great on the trail. Again stiffness and hard ride. 

I have had the best luck with the cheap Crown brand stock replacement springs. They have a softer ride and are fairly flexible on the trail.  They do flatten out sooner than the stiffer springs, but I'm willing to pay that price for the ride and flexibility. I have the mind set that I will probably have to replace springs about as often as I replace tires.

2nd thing on ride comfort. Air pressure makes a huge difference in comfort and performance in these rigs. I like hard tires on the pavement. 30 psi or so. This makes the tires roll easily and I can run her up to 55 mph pretty quickly. Makes the ride a little bumpier, but I'm willing to take it to get more horsepower to the ground, not sucked up by a soft tire. On the trail a soft tire makes life much more pleasant. I usually run 8 psi off road. It really softens up the bumps. Floating over washboards like a Crown Vic. Smile 

If you want to just set it and forget it, somewhere between 15 and 23 psi would probably be a good on/off road compromise. Don't count on that to keep you from sinking in the sand though.

All this is from a guy whose experience has only been on one Jeep and observations of people around me, so as always, Your Mileage May Vary.

Stan
48 CJ2A (Grampa's Jeep)
59 Chevy 1/2 ton
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