Don't swap the Med for Heavy OEM Springs

[cruiserdan]

Originally Posted by Biff

So whats the difference between the J springs and the heavies?

The J's are taller, about an inch I think.

[Montana Cruiser]

Originally Posted by e9999

so basically, if the rates are linear and the same for both heavy and med, and the springs are linear, that would mean that there should be no difference whatsoever dynamics wise between a heavy and a med+spacer the same length, right?

How about sturdiness, stability etc?

This is exactly what I'm getting from reading this ..... however, this would not explain why people with heavies and light additional weight experience a rougher ride. So either this theory is flawed or the people with the heavies and rough ride are "feeling" something thats not there?

[shocker]

Originally Posted by Biff

So whats the difference between the J springs and the heavies?

Think that was covered in post #19

Originally Posted by Shocker

All these springs probably lift the vehicle their stated height if you have the weight on your cruiser that they are rated for. In other words, add 200 - 300 lbs. to the back of a cruiser with heavy springs and it will probably sit at the same height as the mediums without the extra weight.

J spings would sit an inch higher than the heavies with the same weight.

[Gold Finger]

Originally Posted by semlin

we really need an engineer on this thread but here's another comment from a guy with no physics after grade 10.

is arb saying the springs are physically identical except one is longer or are they saying that the springs are physically different so that, even though one is longer, they both have the same load bearing capacity. I think they are saying identical but longer.

assume you have two springs of exactly the same construction but one is longer than the other. Wouldn't the longer spring have a greater weight bearing capacity? under the same load, wouldn't the shorter spring be more compressed in normal operation? I am assuming every spring has an optimum load rate at which further compression diminishes the responsiveness of the spring. I think the longer identical spring will have a higher optimum load rate.

Conclusion? I think heavies are better for more load/weight. How much better I don't know. If you just want to cure stink bug, then spacers may be more appropriate.

I would suspect that the heavies are comprised of material of a lower tensile strength in order to have the same Lbs/inch rating, if you remember that cutting a spring down increases its Lbs/inch rate!

[Gold Finger]

Originally Posted by Gold Finger

I would suspect that the heavies are comprised of material of a lower tensile strength in order to have the same Lbs/inch rating, if you remember that cutting a spring down increases its Lbs/inch rate!

I have that arse about tit I mean a Higher tensile stength

[davisdrafting]

To simplify things you’ll have less space between
your spring coils using short springs+shims compared
to longer springs of the same rate and the same amount
of weight.

What does this mean, simply you’ll have less compression
travel with springs+shims i.e. less space between coils.

[tech_dog]

If I'm reading this, the person from ARB that provided the info got the model numbers backwards. That hardly installs confidence.

There has to be someone who has both heavy and medium in their garage. Can someone rig them up to measure them, load them up with 100 lbs, and then measure them again? That would settle this once and for all.

[sc40]

man this thread is good, but let me get this right,

j's with load siit one inch above heavies with the same load.

and heavies sit one inch above med. with the same load.




right?

[SR.GRINGO]

Originally Posted by cruiserdan

The J's are taller, about an inch I think.

So I'm running the same height as J's with the heavies and two trim packers on each spring?

[alkaline747trio]

Here is what I am gathering from this..

Mediums: 2.5" lift no load
Heavies: 3.5" lift no load, 2.5" lift loaded 200#
J's: 4.5" lift no load, 3.5" lift loaded 200#, 2.5" lift loaded 400#


Sound about right?

[e9999]

my 863s got me 4" of lift with truck empty.
A bunch of recovery stuff in the back, I'd say at least 200 lbs, more like 300 lbs gave a 1/2" drop. A trailer in the back did about the same.

Ride is just fine and it's great to have the extra clearance and not drag the butt any more. Need to adjust LSPV but trivial and there is a bit of rake when unloaded but I don't care. Sure glad I went with 63s and not meds...

[cruiserdan]

Originally Posted by alkaline747trio

Here is what I am gathering from this..

Mediums: 2.5" lift no load
Heavies: 3.5" lift no load, 2.5" lift loaded 200#
J's: 4.5" lift no load, 3.5" lift loaded 200#, 2.5" lift loaded 400#


Sound about right?

No.

[nickw]

So I wonder what springs I should get? Can anyone help?

I was thinking Heavy/heavy.

Up front:
ARB bumber
Warn M8000

Back:
big roof rack
rear ladder
tire carrier and 258/75/16 BFG AT
plus I carry about 100-150lbs of gear.

Getting:
Sliders (as soon as I make em)
Rear drawer system (as soon as I make it)

I was thinking heavy/heavy but mayne I should get heavy/J's?

Thanks,
Nick

[woody]

I run heavy fronts and medium rears (with BroncoII-IIRC bags for towing/loading times - deflated for daily use)

Front has an ARB and a 10k T-Max winch. Std OME lift length shocks all around, caster bushings (installed with Slee's kewl little press dealio).

Prior to the winch/bumper and while running med/med's, it rode a little rough...with the added weight and the heavy/med setup, I'm quite pleased with the daily ride. There is minimal rake as well, sits close to level.

sliders are coming, but that weight is centered and won't effect rake...

[alkaline747trio]

Originally Posted by cruiserdan

No.

Then correct me...

[cruiserdan]

Originally Posted by alkaline747trio

Then correct me...

Search my friend, search.....

An un-loaded 864 lifts about the same ammount as an unloaded 863J (both of which are about an inch or so heigher than an 863). It takes twice the weight to lower 864's to any given height as it takes to lower 863J or 863.

I would not run 864's unless you pack a lot of extra weight all the time.

Read this thread:


http://forum.ih8mud.com/80-series-tech/69927-js-up-front-heavy-rear.html

[Hayes]

We're talking 850 vs. 851 here.
We also seem to be operating under the (logical) assumption that 860 and 863 have the same rate (just like the front), but this has not been explicitly stated.
Anyone?

I think davis drafting (post #36) hit on the only difference between 850 and 851 with spacers. You'll have slightly less travel with the 851+spacer setup compared to the longer 850. But I bet the difference is negligible.

I guess it would depend on the number of coils in the spring. (More coils would "bottom out" sooner)

Springs are interesting things.
My physics go thru college, but I doubt I have a better understanding than everyone else here.

My understanding of springs, as I think through this question:

Per length of coiled spring,

More coils = less deflection per unit of compression = less force to compress = softer spring.

Fewer coils = more deflection per unit of compression = more force to compress = harder spring.

To make the 850 taller than the 851 OME would have to either add more coils, "stretch" the spring, or a combination of both. I would guess that a combination of both would be needed to keep the same spring rate. This would probably also net no change in travel between maximum compression and unsprung length?

Of course, this ignores the effect of different materials in the springs.

Just thinking out loud here.

Hayes

P.S. I haven't had the opportunity to compare the ride of 850/863 vs 851/860, but with a light rear end, the bumps are a bit harsh under the rear axle.

Hayes

[cruiserdan]

From Beo...........

Originally Posted by Beowulf

==============================================

OME Springs:

General rules:
unladen 864=5" lift or 2" w/400 kg load (20mm wire)
....... 863=4" lift or 2" w/250 kg load (19mm wire)
....... 860=2" lift or 1.75" w/a gas tank (18mm wire)
....... 850=2" lift w/some weight(dual batteries etc)
....... 851=2" lift w/bar & winch, dual batteries, etc
....... Stock springs 16mm wire.

================================================

Spring......bar...free.......nbr.....coil......spr ing
number......dia...height....coils....weight....rat e (lbf/in)
..................DS..PS

Front
850.........17mm..495/505mm..9.8.....7.3kg......220 lbf/in
850J........17....515/525....9.8.....7.3........220
851.........17....475/485....9.8.....8.1........220
861.........16....480/490...10.4.....7.0........220

Rear
860.........18....480/490....8.3.....8.1........220
862.........17....460/470....9.0.....8.0........240
863.........19....480/490....8.3.....9.2........250
863J........19....505/515....8.3.....9.2........265
864.........20....480/490....8.3....10.3........320

Spring...bar...free ht...# of...coil....spr rate
number...dia....DS/PS....coils..weight..(lbf/in)
------+++----++-------+++-----++------++--------
850......17mm..495/505mm..9.8....7.3kg....220
850j.....17....515/525....9.8....7.3......220
851......17....475/485....9.8....7.3......220
861......16....480/490...10.4....7.0......220
860......18....480/490....8.3....8.1......220
862......17....460/470....9.0....8.0......240
863......19....480/490....8.3....9.2......250
863j.....19....505/515....8.3....9.2......265
864......20....480/490....8.3...10.4......320

===============================================

OME shocks

............. Open ......... Closed
............ length ........ length
N70 ......... 614 .......... 354
N71E ........ 620 .......... 370
N74E ........ 620 .......... 370
N73 ......... 614 .......... 354
N73L ........ 667 .......... 387
N74L ........ 667 .......... 387

================================================



I see there are a couple of minor discrepancies. As I recall, I got these from 2 different sources.

-B-

[Hayes]

There's the info right there.
860 and 863 have different spring rates.
That would verify the harsh feeling with a light rear end.

I guess the higher spring rate of the 863's are responsible for the increased ride height rather than the longer spring in the 850 - 851 comparison.

Hayes

[Bruneti]

850's would have the advantage of no spacers to fail or flatten.
851's + spacers has the advantage of lower cost if you already own the springs and don't mind risking a spacer failure and it's fairly low cost replacement.

If you don't own either set yet, I believe several people have run the 850f/860r combo successfuly with a stock bumpered rig and been level without any spacers. I'm sure every rig differs a bit, so there may be no perfect answer.

CDan - Thanks for re-posting the spring info that Beo had put together. Does anyone know the spec's on Slee's 4" lift and how it fits into all of that info? I would love to know the spring rates that are used on his 4" kit, but haven't asked to see if it's "confidential" or not.

[XXXR]

And finally... when I do run the ARB Bullbar and add the 10mm spacers... how does this throw off the caster? What about alignment? I'm also running light springs in the front. (851's)

[semlin]

xxxr your questions are really for another thread. stock caster varies on 80s as does the impact of bumpers and spacers between trucks. The short answer is that once you do it you will need to have your resulting caster measured then proceed accordingly. if you are very paranoid have your stock caster measured and we can then make an educated guess of the impact but it would be such a guess that I would not waste my money.

[XXXR]

Originally Posted by semlin

xxxr your questions are really for another thread. stock caster varies on 80s as does the impact of bumpers and spacers between trucks. The short answer is that once you do it you will need to have your resulting caster measured then proceed accordingly. if you are very paranoid have your stock caster measured and we can then make an educated guess of the impact but it would be such a guess that I would not waste my money.

I'm running the 2.5 lift with the caster correction bushings... I just wondered if the spacers would raise the front enough for it to be an issue, or if the Bar would sink it enough to return to it's proper height. I ordered a set, as I plan on a bar next year.

You're right though, this is a specific that relates to caster and not just spring height.

[XXXR]

So... ya'll think I need the spacers with an ARB Bull, winch ready, but no winch uninstalled?

I purchased a set of 1.25 (I think, I know they are just over an inch from Man O Fre) spacers for when I add the Bull. I was looking forward to leveling the rig out anyway, but I don't want to run with the rear squat either. Anyone run this?

THANKS!

[dmc]

A good reference page since ARB's site is less than stellar...

OME spring rates

I won't get into what everyone should run on their truck. My preferred set up is J's up front and 863s in the rear. Sat level and rode great. Don't ask why I don't run it anymore. i'm dumb.
dmc

[frankies off road]

two diffrent springs of the same rate one being longer,the longer spring will still have a stiffer rate because there will be more coils for compresion,coil spring gain rate as the coils are compresed.so more coils to compress more actual spring rate.

[ed97fzj80]

Originally Posted by dmc

I won't get into what everyone should run on their truck. My preferred set up is J's up front and 863s in the rear. Sat level and rode great. Don't ask why I don't run it anymore. i'm dumb.
dmc

What shocks did you use -- Ls up front and ordinaries in the back?