I've posted this before, but IMO, even 650 is too high unless you've got a plate bumper and a winch on it. I don't know why so many guys run such heavy springs. Our trucks are light. Having such heavy springs limits movement, which negatively affects handling on any terrain, and reduces ride quality.

I'm running 10" 600 lb springs, and it's not a hell of a lot better than the TB ride. I'm swapping out to 12" 500 lb springs this spring. My 10" ones are cranked all the way, and I'm not sitting quite as high as that.

While I'm on the subject, as you can see by getrdone's pics, you can not run a coilover setup cranked all the way up like that because the upper control arms swing down into the coils.

 

what's the reasoning behind going to the taller spring?

 

Because the original factory made RCD coilover suspension kit came with 650's and countless people mentioned that they sag within 12 months of the initial install. The people that had plate bumpers experienced it as soon as 4-6 months - This is back in 2009. It was a well-known issue with the RCD suspension setup.

That's why everyone started going to the 750's for a stock setup, and even 800+ for those with heavy plate style bumpers.

 

Maybe if they are "cranked all the way" your springs are coil binding and causing the rough ride? Post up a pic of your current setup so we can see how it compares. Something is amiss here why there is such a range in springs between similar trucks.

 

Is that a function of the springs used? for example, would a better spring not be as susceptible to sagging?

I would think that a lighter spring would be more likely to sag over time.
Are spring rates manufactured differently by varying the diameter of the coil rod, or spacing between the coils? assuming a constant spring diameter.

 

Not really - The springs rating is the springs rating. It's a defined unit of measure that's universal across manufacturers.

From Pirate4X4.com (Coilover Bible - Part #1):
Coil springs have a rate – a description of how stiff they are. The rate describes how much the spring will deflect (compress) for a given load (weight) placed on it. The rate is measured in pounds per inch. The greater the rate, the stiffer the spring, and the more pounds of load it takes to compress the spring one inch.

Yes, but a given spring rate is still the spring rate - it's defined.

From Pirate4X4.com (Coilover Bible - Part #1):
Four things determine a coil spring’s rate:
1. The material from which it is made (the “torsional modulus” of the material, in psi)
2. The diameter of the wire from which the spring is wound.
3. The diameter into which the coils are wound – the Coil Mean Diameter.
4. The number of active coils in the spring

 

I see. Well I understand that spring rating is a defined quantity, but I was curious about the sagging. Since there are multiple factors controlling spring rate, for example, would a larger diameter wire with fewer coils be less prone to sagging than a spring with a smaller wire, but more coils (assuming both have the same spring rate)? That's more of a rhetorical question, since it's probably pretty complex, but that's what I was getting at.
Sagging means that the spring rate over time is decreasing due to weakening of the material.
I'm sure there are probably some materials that can be used that will not sag (within reason). Just curious if there are options as far as that is concerned.

 

The more "overloaded" a spring is the more likely it is to sag. Just as a spring that is on an offroad truck that gets flexed more is also more likely to sag.

 

I know you said it was a rhetorical question - But, in the real world - any difference would be negligible.

If they both have the same spring rate - they will both sag at the same rate when subjected to the same loading - Note: I'm talking reasonable real world terms when I say 'same' - Not technical lab type results.

That resistance to compression is what determines the springs rate to begin with.

 

Because with the 10" 600 lb, I don't have any more room to increase height. With the 12" 500 lb, I'll be setting the adjustment right in the middle, since there is about 5" of height adjustment on the shocks. I have the 6.5" travel shocks, too, even through I'm not SL'd...I plan on adding the SL soon, but at the height I'm riding, the 6.5" works quite well.

Must have been their springs, although I thought they used Eibach, which are a quality spring. I've had my 600 lb on for 16 months, and there is absolutely no sag.

No, I'm not in coil bind, they're just stiff. At ride height, I can stick my fingers between the coils. I think logan03CO hit it on the head: people are trying to avoid sag. Our trucks are not heavy enough in stock form to warrant more than 600 lb springs if they're good quality. Even with a plate bumper, I wouldn't go any higher. Add a winch to that, and I might consider stepping up to 650 or 700, but guys running 700 on a stock truck have got to be getting close to zero suspension movement under normal driving without additional weight.

 

A larger diameter wire with fewer coils would definitely sag less, because it would be a higher spring rate. The equation is rather complex, but basically, less coils equals higher rate, and thicker wire means higher rate. Coil diamter also comes into play, but a spring with thicker wire and less coils would be considerably higher rate than more coils and thinner wire.

 

Say what you want but I have suspension travel and the ride is nice, better than my torsion setup. I don't have a whole lot to compare to so maybe a lower weight coil would be noticeably better, but I'm very happy with my setup, the rear is what stiffest for me.

Maybe since mine have miles on them they have softened up, but I like these coils since I plan on swapping a 5.0 and will probably have a plate bumper at some point.

 

That underlined portion is the key.

However, SteelDirigible was asking a hypothetical about resistance to sagging between his two presented options & he stated that they both had the same spring rate - Which is why I posted that in the real world, any difference in 'sag' would be negligible because they have the same spring rate.

 

Well i dont know what to do now since my truck is in pieces, my springs are too stiff/too long. I will now have to spend more money to get shorter springs or maybe softer 12s but no one knows which...awesome anyone know how to take the springs off im guessing you have to take them off from the long rod end but how does one hold the shaft in order to remove the long rod end off?

 

Assuming you have Fox brand coilovers: Installing & Removing Springs - Fox Coilovers

 

I'm very interested in how this is going to work out. My new coil over brackets should be here this week and I'll hopefully be ordering fox 2.0 and springs next week. At this point I'm thinking 12in 650lb?

 

Thanks for the info, now any ideas if i should get a shorter coil at higher lbs or stay with the 12s and just go real soft, This will be for ride comfort very minor to minamal off roading

 

Assuming these are going on stock height trucks (aka - non-superlifted) & using Fox coilovers in the 5" travel variety - I would stay away from any type of 12" spring (regardless of spring rate).

Look at the pictures Getrdone52 posted from yesterday - This combo lands too high up on the coilover body and will conflict with your upper control arms.

 

Thats what i figured, wish someone would have said that when i asked last time now ill be out a 100 buck for new.

 

I may have mixed up what happens when changine the number of coils vs wire diameter, but logan gets what I was asking. I guess what I wanted to know is if one of the factors has more effect on sag over time.

I understood "sag" to be the reduced spring rate over time. I understand that when new, the same spring rates on the same length spring will have the same sag, but over time, will they degrade at the same rate?

Thanks for deealing with my questions... you guys have been very helpful in my quest for knowledge!

 

I would assume they could degrade at slightly different rates due to the differences you already stated (metal properties etc.). But again, I see it being a negligible amount.

It certainly wouldn't be drastic enough to entertain a change in spring rate (or even trigger a decision to pick a different quality manufacturer) in an attempt to account for the slight differences in construction properties between what two manufacturers used to obtain a given spring rate in the first place.

Long story short(er) - The tendency of springs to sag over time, is more closely related to the overall load rating of the spring, than the subtle differences between how two quality manufactures may have obtained that given rating.

 

Has anyone tried 2.25 ID springs? In the pics from page 51 it looks like there would be enough room not to rub the shock body. Might help with the UCA clearance issues.

 

Nope.

According to page #15 of the Fox catalog (Available for download from this page: Offroad Shocks | FOX), the 2.0 series coilover is designed for a 2.5" I.D. spring.

I believe that's pretty standard.

Because remember, even using the recommended 2.5" I.D. spring only allows for a .25" gap around the outside of the 2.0" O.D. body.

 

Is it just me or does it look like the shock isn't very far extended. I'm thinking that should be pretty close to full droop so there should be close to 5in of shock shaft sticking out. I realize that's what limiting straps are for but it looks like the shock will bottom out before the a-arm get's close to the factory bump stop. Maybe the extended eyes move the shock down too far for the way the brackets were originally designed?

 

You shouldn't have bumpstops after the coilover is installed. They have to be cut off to make room