Lift springs-- 4" vs 6"

[Skandocious]

So eventually I'll be investing in some Skyjacker Softride lift springs to replace my stock + 2x AAL setup. I did a lot of research and people rave about the Softrides-- it's a progressive rate spring so it still handles the same payload but has a smoother ride when unloaded. Having 2 AAL's added to each side of my rear end really makes for a rough ride, not to mention the fact that old springs + new steel = separated leaves. The AAL's are forcing my packs apart; so much so that it actually snapped the spring pack straps that wrap around the packs. So as soon as I can work up the funds I'll be buying a set of Softrides.

The question is-- I need a total of 2.5" of lift on the rear (4" lift kit = 4" front / 2.5" rear). The lift springs that would fit my application are the FR52S springs; skyjacker says they are for 1-4" lift applications. They ALSO have the FR54S, which is for 3-6" lift applications. But they say that with the 54S you can remove the stock blocks to reduce the amount of lift by 2". Although they're slightly more expensive, I like this idea better because then if I decide to lift it 2 more inches down the road (which I've thought about doing from time to time) I could just throw the blocks back in...

So it's either FR52S with stock 2" blocks
-or-
FR54S with no stock blocks

Is there a disadvantage to running without the stock blocks? I can't seem to think of one... Best I know, lift blocks are always frowned upon but do the stock blocks serve some sort of special purpose?

 

[LEB Paul]

You'd be better off without the blocks, all they do is create more axle wrap because of the added leverage of the axle against the spring pack. If you've taken any physics courses think of it as a moment arm, or just leverage in general. The further from the spring pack, the more easily the axle can twist the springs, especially if you're going with softer ones.

 

[Skandocious]

Oh I understand axle wrap completely, and I understand that the longer lever arm is the reason that you don't want big lift blocks. I just didn't know for sure if there was a reason that the geometry of the drivetrain made it preferable to have a little bit of space between the axle housing and the spring pack. No reason to have a block between?

 

[1985 Ford F-150]

Ford just did it to raise the 4wds more than the 2wds for ground clearance.

 

[surewhynot]

I am assuming that 4x4's came with blocks for a couple of reasons.

Cheaper than higher arched springs
Better ride from springs with less arch

 

[Skandocious]

You think I'd have better ride quality if I kept my stock blocks and used the smaller skyjacker lift springs?

 

[surewhynot]

I dunno. Personally, I'd rather have a truck ride like a truck and get more payload capacity without sagging. I'm not sure what your exact preferences are.

If you can go without the block, you'd be better off as far as wheeling it goes.

 

[Skandocious]

I dunno. Personally, I'd rather have a truck ride like a truck and get more payload capacity without sagging. I'm not sure what your exact preferences are.

I'm on the same boat. I don't want to sacrifice payload-- but that's the beauty of progressive rate springs. As the spring compresses under load it becomes stiffer. So when the truck is unloaded the springs are soft and cushy then under load they stiffen up and support the weight.

So the question is... Will the 4" lift springs support the same amount of weight (under load) as the 2" springs?

 

[surewhynot]

That is a question that I can't answer. Here is what I can tell you from personal experience. The more arch, the stiffer the ride. My 6 inch springs don't ride bad, because they are progressive, but they do sag under load because of design. A progressive spring has to sag a bit before it hits the sweet spot, so to speak.

I would go a little higher than you want your final ride height to be. Even good springs will lose a little arch when they settle in. You may want to account for about an inch. My pro comps sucked. They settled about 2.5".

 

[Skandocious]

Which springs are you using now?

 

[surewhynot]

Skyjackers. 6" progressive.

 

[surewhynot]

In this pic, I have about 750 lbs of tongue weight on the trailer. That took the *** of the truck down about 2 inches.

 

[Skandocious]

Your using softrides?! Why didn't you tell me? Do you like them?

 

[1985 Ford F-150]

Well yours is a half ton aint it Tony? Chris itll still squat when ya get wieght on the back end either way. Its a half ton and they squat a ton cause theyre not meant to haul heavy loads. If ya dont want it to squat then get stiffer springs or get over loads. Its kind of a give and take deal how much are ya gonna haul with that truck and how often are ya gonna do it. Since your worried about the ride quality then id say just get the skyjacker ones that match your fronts. If it squats so what.

 

[Skandocious]

Well yours is a half ton aint it Tony? Chris itll still squat when ya get wieght on the back end either way. Its a half ton and they squat a ton cause theyre not meant to haul heavy loads. If ya dont want it to squat then get stiffer springs or get over loads. Its kind of a give and take deal how much are ya gonna haul with that truck and how often are ya gonna do it. Since your worried about the ride quality then id say just get the skyjacker ones that match your fronts. If it squats so what.

This is pretty much the direction I'm heading. I don't haul very often... It's possible that I'll be towing our 7000# boat every so often (with a fairly heavy tongue) but if I do then it wont be very often because usually my brother pulls it with the PSD.

I'm not super concerned about ride quality. I do want to maintain my payload and when I saw that the progressive rates gave me the best of both worlds I started going in that direction.

At this point I'm thinking I might just go with the taller springs and lose the blocks in case I want to lift more later (and I might).

 

[LEB Paul]

Agree with everyone else for the most part. Just wanted to add that if you give them a call and tell them exactly what you want they may be able to get you a custom deal or set you up with a different set of springs that'll work better. Can't hurt to talk to someone in the business.

 

[blackhat620]

I am assuming that 4x4's came with blocks for a couple of reasons.

Cheaper than higher arched springs
Better ride from springs with less arch

I will add one more reason to Tony's list.0,

Tapered blocks to achieve the proper driveline angle. (Chris i cannot remeber if the OEM blocks are tapered on your truck, i do not think they are but double check).

Also as Paul said, call Skyjacker and talk to them, they have been in business for a long time and i am sure they can give you some good pointers.

 

[LEB Paul]

^That too about the tapered blocks, I was going to add that but forgot lol. My bronco has them, not sure on your truck. Probably not with as long as it is, but can't hurt to check!

 

[Skandocious]

Yeah I've seen the tapered blocks on the broncos-- mine doesn't have 'em.

 

[surewhynot]

Your using softrides?! Why didn't you tell me? Do you like them?

I would have told you, but you don't get up early enough to answer the phone.
As far as I can tell, they're pretty good. Only time will tell if they de arch like the pro comps did.