Progressive vs. Linear springs (1 Viewer)

Joined
Jan 14, 2012
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658
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Fontana, CA
Hey fellas, I wanted to know what your thoughts were as a consensus of progressive rate springs.

I have the Icon 3” lift but when loaded down it might only be an 1 1/2” in some cases. Therefor I’ve compensated, (insert joke here) with some helper airbags.

I now consider moving to a Dobinsons 4” lift spring, 700lb rate in the rear...maybe I should just switch out the front as well?
On the rare occasion I put the truck through its paces is some higher speed stuff it’s over far too soon, (insert another joke here).

I hardly think the dampening or default valving on an Icon stage 3 kit will be widely affected by going to a linear rate spring. Let me know what your thoughts are.

Thanks in advance.

Saul
 
Joined
Mar 28, 2010
Messages
707
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FOG TOWN->SF<-
3 words.....

Tried and True.

These spring companies have been around for over 20 years, no one has complained of sagging over time.

slee spring and OME 850j/864 (with spacers)

all those other Mumbo Jumbo will sag and not carry the weight over “long” periods of time. In other words “sag”.
 
Joined
May 26, 2005
Messages
7,901
Location
Phoenix
Hey fellas, I wanted to know what your thoughts were as a consensus of progressive rate springs.

I have the Icon 3” lift but when loaded down it might only be an 1 1/2” in some cases. Therefor I’ve compensated, (insert joke here) with some helper airbags.

I now consider moving to a Dobinsons 4” lift spring, 700lb rate in the rear...maybe I should just switch out the front as well?
On the rare occasion I put the truck through its paces is some higher speed stuff it’s over far too soon, (insert another joke here).

I hardly think the dampening or default valving on an Icon stage 3 kit will be widely affected by going to a linear rate spring. Let me know what your thoughts are.

Thanks in advance.

Saul

It sounds like you're asking what you will lose by going to a linear spring. When I went the other way, from Slee 6" linear to 'progressive' 4" Dobinson Flexi coils plus spacers, I gained a smoother transition between unloaded and loaded states, and a seemingly smoother ride overall and especially on surfaces with lots of small bumps, like washboard. However, it wasn't a night and day difference. It might be a lot more dramatic going the other way. Some of the improvement I felt is attributable to a lower spring rate, so it's hard to say how much of a difference the 'progressive' element provided.

Have you measured your lift? Looks can be deceiving. If you're truly losing that much height, I'd start with spacers, as that will maintain the ride characteristics you currently have. And it's a cheaper experiment, and easy to sell if you decide you don't want them.

Nobody that I'm aware of makes a 700lb rate spring for 80's, most are 200-350 lbs per inch. 700lbs/inch on an 80 would be rock hard. From what I can see on Dobinson's website, they have a 4" lift linear rear spring (C59-313) designed to carry an extra 220-750lbs over stock but that's not a spring rate, it's more of a capacity.

3 words.....

Tried and True.

These spring companies have been around for over 20 years, no one has complained of sagging over time.

slee spring and OME 850j/864 (with spacers)

all those other Mumbo Jumbo will sag and not carry the weight over “long” periods of time. In other words “sag”.
All springs can fail. I have personally broken both a front and a rear Slee 6" spring. Categorically saying that 'anything I don't understand won't work' is pretty narrow minded.
 
Joined
Jan 14, 2012
Messages
658
Location
Fontana, CA
Yes, let me clarify a bit. I meant 700lb constant load rate, not 700lb per inch.

I do have 30mm spacers out rear and with them installed the rear is about 1/4 lower then the front with the usual recovery gear, fridge, rack etc. During our travels as a family it's not farfetched to load an additional 400-500lbs in the rear. Mind you this is with a airbag at 0psi or ambient pressure which might provide a hair of help but not much. I will be sure to get measurements next time when loaded down at all various weights.

I reached out to Icon long ago about the caster bushings not being up to par for the kit I bought and they mentioned I might be yielding more than 3" out of the front. I ended up picking up a set of Delta VS arms to correct that and the truck ow has 3.2-3.4 degrees of caster.

The airbags intended purpose were for towing. Attaching my 1700lb car hauler trailer will easily drop it another inch but if the airbags are maxed out to the MFR's spec (35psi) the truck can sit just a tad of stink-bug, but towing anything pushing the outer limits will put a large amount of sag still.
 

GW Nugget

Do the best you can with what you have...
Joined
Jul 25, 2014
Messages
3,299
Location
Coalinga, CA
From memory, the Icon 3" lift is not meant to carry heavy loads.
A 700 pound rate linear sounds very extreme.
Generally 80 series HD coils range from 250# to 350# rates.
A Slee 4" HD lift sounds like what you might be looking for if you run your rig heavy.
My 75mm HD Slinky has been good to me. I towed a 5K trailer loaded with adult size kids from Cali to Canada & back on 160#/320# rear coils. They felt firm & predictable.
In my mind linear rate is for a constant load, dual rate coils are good for loaded & unload situations. Best of both worlds.
 

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