Is 2.5” with longer shackles better ride than 4” lift

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Apr 9, 2017
I have been searching this forum google and safari for over a month for this answer. I’m sure it is on here but I must be using the wrong words. I have a 10/70 1971 FJ40. I have stock suspension and I am about to put on my new 33x12.5x15 BFG. My fenders are cut by P.O. poorly I must add, and I am looking for the best ride I can. I am a trail guy with minimal rock crawling. If the trail is blocked by a rock slide I will try to get over it. I also want the best on road as I can. I will run the same size spare off the back and maybe a Jerry can in the future. I understand it is a short wheel base so I’m not expecting a miracle but better than what I have now. I want to do a SR and wondering if putting a 2.5 on the rear with longer shackles to make a 4” lift would ride better than 4” lift springs. Also I want a minimum of a 4” lift. Thank you for any and all opinions you may have.
If you do a shackle reversal up front you'll have to mix and match parts to get the lift you want and a level rig.
So are you saying no SR with a 4” lift?
you have the "best" ride you're going to get, right now.
any new springs are going provide a stiffer, bouncier ride.
with that said, skyjacker 4" springs, no SR.
Couple ways you could do this. In the front you could run old man emu 2.5" lift springs with the shackle reversal kit which would give about 4" of lift. You will have to make sure your driveshaft doesn't bind. In the back you could run some 4" alcan springs. Or some 4" rear fj60 springs with short side forward but install adjustable spring perches but would stretch the rear wheelbase 1.5". You could also do OME 2.5" rear springs with really long shackles but the rear may sway a bit around corners. You could also have alcan or Deaver make you some rear springs according to what you want. You could also do OME 2.5" lift all around with no shackle reversal and do a 2" body lift.
Wow lots of info. I think I will go with 4” lift in the rear for on road handling and research a little more for the front SR lift. Thanks for all the advise!
Another option is to get the 4" springs and remove a leaf. It should put you somewhere between 2" and 4" and ride softer as well. I had 4" SUA springs front and rear and they were so stiff and the truck was so tipsy that I was afraid to take it off road. I pulled a leaf from each pack and now it is perfect. It dropped about .75". Shackle angles are better. It actually flexes. Huge improvement. The most improvement was due to the removal of the leaves in the rear. The front was pretty much okay. The rear was stiff as hell before removing a leaf.

Before three wheeling and feeling like it was going to flop:


After removing a leaf and lowering bump stops. All four wheels planted and truck remains mostly level:

bump stop 5.JPG

Same ditch. Same spot.
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@roadstr6 nice rig. That may be a great idea! Yours looks perfect! Although I’m an old Honda ATC 3 wheeler. It brings back memories. Haha.
@roadstr6 nice rig. That may be a great idea! Yours looks perfect! Although I’m an old Honda ATC 3 wheeler. It brings back memories. Haha.

Thank you, sir. I'm an old Honda guy too, but I prefer mine in the 2 wheel variety.
It's all about the springs and no one makes a spring for the 40 that rides well. The old Man-a-Fre tried with the Mohaves but it was bad timing
( '09 bank crash ) and they didn't sell well enough. Now Man-a-Fre is now under new owners.
It can still be done but one set at a time is nearly 1200.00. I still build about one or two sets a year





Absolutely depends upon quality (features) of the spring!!!!!! Before Downey build NHK 4" lift springs (none better/none softer) we sold Rancho 2" lift springs. Although the Ranchos were nicer than some of the others on the market at that time, they were still too stiff. Back in the day spring features stacked up like this:

Downey springs had 9 features to give them softer ride/longer life.
Stock Toyota Springs had 7 of those features
Rough Country Springs had 7 of those features
Rancho Springs had 3 of those features
Burbank Springs had 0 of those features.
..but rancho's spring rates for the 2 1/2" front is 390 in/lbs, the Mohave was 195~225, depending if you used the option "2F" leaf.
195 was for the V-8s. Rancho's rears are 290, Mohave was 175 ~ 215 , optional leaf for those with hardtops, aux tanks, roof racks
and tire carriers. The rear was a 6 leaf pack , the front was seven leaves. Thin leaves with a lot of free arch. The rears had 11" of free arch.
There were 4" long 16 gauge spacers between the leaves at the center pin combined with the teflon buttons at the ends of each leaf.
This left a gap between leaves eliminating most of the friction between the leaves. Less friction means faster cycle times and a faster response to bumps. With 11" of free arch and that spring rate a typical 40 would squat to a 4" lift. It required 2.5"~3" over shackles as the springs were about 3" longer than stock, 2~2 1/2 longer than most 2.5" lift springs. It allowed 10" vertical travel measured at the shock . You could drive up on a 33" tire and the other three would stay planted.
It did, however, require changes in the front. A shackle reversal, 80 series front driveshaft slip and yokes and taller shock towers to get the most. The stock towers weren't tall enough for a 10" travel shock. Stock 40 or 60 series ujoints wouldn't handle the angles at droop. The 40 and 60 have 24~27 degrees of articulation vs 45 degrees on the 80 front. The 80 rear uses the same low angle joints as the 40 and 60. The 80 slip yoke has almost 3 times the spline length as the 40 and double the 60 for the extended travel .
The complexity probably swayed some away from the system. There is no simple long travel, Cadillac riding bolt on answer. Short leaves are hard
to get a great ride out of. If you've ever ridden in a CJ5 or a mid 60's Scout you'll understand

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