Questions About Shocks/Springs Ram 2500

ttengineer

Adventurer
Honestly I wish I would have tried shock tuning before ditching the Carli suspension. ...

It's not as simple as selecting coils just to achieve ride height. You can achieve the same ride height with two completely different coils. Coil length is equally important to coil rate. With that said, no one is arguing that shock tuning is critical.

It is that simple.

You figure out where you want your truck to sit in the suspension. Then you size the coil for your desired coil rate based on up and down travel desired. Then you size you shocks and tune them to your desired characteristics.

That’s literally how it’s done.

Yes you can get the same ride height with different coils. But they will not be same same rate or length.

Shocks are still the deciding factor in how those coils preform.

A coil can only do two things, compress and rebound. It’s not magic. Yes a coil can be out gunned if you’re carrying too much weight, but it will just compress and sit on its bumps. If the shocks are under valved it will act all squirrelly. If they are over damped you’ll get axle hop.

Carli coils aren’t even all that much lighter than stock. Maybe 20%.

I think Thuren uses like an 18% softer rate.


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WILDPEAK

Member
Carli coils aren’t even all that much lighter than stock. Maybe 20%.

I think Thuren uses like an 18% softer rate.

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Appreciate the response, and vehicle dynamics 101 here :) The OE PW coils and the Carli coils are too soft for 9k +/- in my experience, the Thuren are likely too soft as well.

The vehicle would slowly oscillate side to side on the highway around curves, the shocks were doing work, slowing the oscillations, but sometimes the truck would come to near stop from 70mph automatically once the yaw sensors triggered ...

For a mix of crawling and go-fast, a good setup would combine ample downtravel and ample uptravel respectively. Ride height centered in the suspension travel would be a good starting point in my opinion. The AEV lift I think has about 10-11in travel Bilstien shocks, my rear bump stop gap is around 5in light load and 4in full weekend load, so somewhat centered in the travel, but with more uptravel.

One consideration not often discussed is center of gravity vs coils and swaybars. Shocks control the speed of compression and rebound, not whether the vehicle begins to sway to one side in the first place. When you add payload on a pickup truck you increase COG. Combine that with bigger tires and a mild lift, you need to counter the raised COG to maintain highway handling. Yes countering the raised COG with with stiffer coils or a stiffer swaybar will be a compromise off-road whether go-fast or articulation or both. I suppose I'm contemplating whether or not a longer coil than OE but stiffer than Carli/Thuren would be a solution? Or go soft coils in the rear, shocks tuned to the load, and stiffen the rear swaybar ?

I'm not opposed to going Carli (again) or Thuren to gain the off-road go-fast capability knowing I'll likely have to do airbags and Daystar cradles like many others have done it just doesn't seem like the "ideal" solution ?
 
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I don’t know if I’m as heavy as you fully loaded, but probably close (ignore trailer)

I have the heavy ARB bumper, a 37” spare on tray above bed rails, rack/tent, 2 jerry cans of fuel, 20ish gallons of water and all the camping gear + family when we head out for 10 days or so. My COG way above stock!

I experienced the 70+ mph highway stability control fiasco on stock suspension and 35s. I kept the PW OE rear springs with a 1” spacer, and upgraded front springs to Thuren, King 2.5s, and Thuren track bars. Honestly I think the rear Thuren track bar made a huge difference in highway sway. It will still do it, but in less situations and clearly not as much as OE despite the higher CG I have now. I’m now to the point that I can see the road features coming that will cause it and I just breathe down to 65mph and no problems. On long highway trips from Detroit to Moab and back there are about 5 such locations - other than that I generally run 5 over speed limit without issue.

Thuren did also valve the rear 2.5s for my setup, heavy on rebound and that probably helps too... but my gut says the rear track bar is the biggest improvement.

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I think you guys are demonstrating exactly why RAM reduced the GVW on Power Wagons to 8565lbs from the 10,000 for the other 2500 models. Your COG is already higher due to the lifted springs on the PW, and you are both actually referring to "roll center". I'm no expert, but think of roll center as the magic point where the COG acts on each axle when you change direction.

The AEV kit and Thuren and Carli track bar kits modify roll center to a small degree by changing the relationship of where the axles pivot. Otherwise, short of a custom suspension where the geometry is more radically changed, we're limited to using springs, shocks, and swaybars to tune suspension performance. Every suspension setup is a compromise, and I think we each have to decide what your top priority is, and where you're willing to compromise. The PW setup stock gives excellent trail performance with added articulation over stock, but loses load and some higher speed pavement control. My opinion from armchair research only, is Thuren and Carli have great functioning products, but are directed toward performance with light loaded vehicles. I haven't found anyone presently offering springs with progressive or constant rates and some lift, closer to the factory springs. The airbag addition stiffens the spring rate to enable higher loads, but has it's own set of issues and compromises. Longer springs aren't necessarily better, as they might be softer but may not offer as much compression

So, seems like you pick a compliant off-road suspension and maybe add adjustable items (airbags, shocks) which enable stiffening when on the highway, or slightly de-tune the stock suspension to have some trail performance. I think lockers offset lack of articulation on the trail, to a degree but no doubt the ride isn't there. The Aussie's do a much better job aftermarket IMO providing suspensions that balance trail and street, and offering different options depending on load; maybe OME will show the 2500 RAM family some love in the future?

Sorry if I'm stating the obvious here, but not sure what you are really trying to improve from your already excellent vehicles. Highway load carrying?
 

WILDPEAK

Member
I think you guys are demonstrating exactly why RAM reduced the GVW on Power Wagons to 8565lbs from the 10,000 for the other 2500 models. Your COG is already higher due to the lifted springs on the PW, and you are both actually referring to "roll center". I'm no expert, but think of roll center as the magic point where the COG acts on each axle when you change direction.

The AEV kit and Thuren and Carli track bar kits modify roll center to a small degree by changing the relationship of where the axles pivot. Otherwise, short of a custom suspension where the geometry is more radically changed, we're limited to using springs, shocks, and swaybars to tune suspension performance. Every suspension setup is a compromise, and I think we each have to decide what your top priority is, and where you're willing to compromise. The PW setup stock gives excellent trail performance with added articulation over stock, but loses load and some higher speed pavement control. My opinion from armchair research only, is Thuren and Carli have great functioning products, but are directed toward performance with light loaded vehicles. I haven't found anyone presently offering springs with progressive or constant rates and some lift, closer to the factory springs. The airbag addition stiffens the spring rate to enable higher loads, but has it's own set of issues and compromises. Longer springs aren't necessarily better, as they might be softer but may not offer as much compression

So, seems like you pick a compliant off-road suspension and maybe add adjustable items (airbags, shocks) which enable stiffening when on the highway, or slightly de-tune the stock suspension to have some trail performance. I think lockers offset lack of articulation on the trail, to a degree but no doubt the ride isn't there. The Aussie's do a much better job aftermarket IMO providing suspensions that balance trail and street, and offering different options depending on load; maybe OME will show the 2500 RAM family some love in the future?

Sorry if I'm stating the obvious here, but not sure what you are really trying to improve from your already excellent vehicles. Highway load carrying?

I second your thoughts here especially about the Aussies. Ive exclusively owned Toyotas prior to the RAM 2500, a FZJ80, a 3rd gen Tacoma (for a very short time), had OME on both. The Tacoma OME BP-51 system was completely mis-matched to stock unloaded truck, by design, it was made for bumpers/armor/cargo. HOWEVER, I loaded down the Tacoma with the BP-51 suspension (armor, recovery, shell, gear), it was hands down the best suspension system I've ever ridden on for an Exped rig.

Point being, Carli/Thuren are tuning aftermarket coils and shocks to unloaded trucks, nothing wrong with that. But there's clearly a market for full size expedition rigs, AEV could use some competition in this space.

Ps. If you check out Trucks n Toys in Australia on IG they are starting to figure out these RAM Platforms as well, using Fox 2.5s, but a lot of these guys are super heavy running Kelderman air.
 

WILDPEAK

Member
I don’t know if I’m as heavy as you fully loaded, but probably close (ignore trailer)

I have the heavy ARB bumper, a 37” spare on tray above bed rails, rack/tent, 2 jerry cans of fuel, 20ish gallons of water and all the camping gear + family when we head out for 10 days or so. My COG way above stock!

I experienced the 70+ mph highway stability control fiasco on stock suspension and 35s. I kept the PW OE rear springs with a 1” spacer, and upgraded front springs to Thuren, King 2.5s, and Thuren track bars. Honestly I think the rear Thuren track bar made a huge difference in highway sway. It will still do it, but in less situations and clearly not as much as OE despite the higher CG I have now. I’m now to the point that I can see the road features coming that will cause it and I just breathe down to 65mph and no problems. On long highway trips from Detroit to Moab and back there are about 5 such locations - other than that I generally run 5 over speed limit without issue.

Thuren did also valve the rear 2.5s for my setup, heavy on rebound and that probably helps too... but my gut says the rear track bar is the biggest improvement.

Appreciate you posting up your experience. My gut tells me also the AEV raised trackbar (and Thuren raised trackbar in your case) is very beneficial to how these trucks handle from a roll center and highway stability point of view. I'd like to move from AEV to Thuren trackbars to get away from the rubber bushings for more straightline highway stability.

I don't really want to resort back to Carli nor OE Power Wagon springs nor move to Thuren springs especially in the rear.... I am not willing to experience the phenomenon you described again. It's difficult to isolate if it's just the rear coil rate or the coils and shock valving on all 4 corners...

I have to be real with myself about how the truck gets used. It's a weekend warrior that involves driving on the highway for extended amounts of time to get to remote destinations, remote trailheads, remote campsites, etc.. It's not a rock crawler or baja rig, although I want it to be both of those! I have to prioritize highway safety... I've started to remove as much weight as possible but I'm still scared to go to a lighter spring again.
 

jadmt

ignore button user
Found something really interesting when running my power wagon's coil part numbers. Totally different than I thought would happen.
 

WILDPEAK

Member
Found something really interesting when running my power wagon's coil part numbers. Totally different than I thought would happen.

These are the springs that came off my 2017.
There are 4 different part numbers for the front left/right + rear left/right as I recall. I'm sure you will find the non-PW springs listed as well if you browse a Mopar online dealer...?
 

jadmt

ignore button user
These are the springs that came off my 2017.
There are 4 different part numbers for the front left/right + rear left/right as I recall. I'm sure you will find the non-PW springs listed as well if you browse a Mopar online dealer...?
both left and right are the same on mine but what I found strange is my power wagon fronts and rears have the same part number as a 2500 diesel coils off of a laramie, limited or longhorn. I thought they would be power wagon specific. So it is not the coils that give the higher payload on the other models.
 
Wildpeak, former Toyota guy here also, with 3 old ones still. My RAM is a whole new adventure and why I'm reading your thread. We've been touring in a built FJ-60 for a long time, often overloaded and I really liked the fact that I could select different stiffness springs (leafs) depending on load when I put it together. I was fortunate to spend 2 months in Aus, back in 2002, touring the East coast with a rented full overland diesel Land Cruiser w/rtt. Really opened my eyes to the practicality of mods. Aus has some interesting laws with lift and GVW's that force them to be pretty creative. I've seen the SuperRam info and keep monitoring to see if/when someone over there will start making suspensions.

I'm coming at this from the other side: I bought mine (Tradesman diesel) to haul a Black Series HQ-19 travel trailer, and so the priority is payload and towing, but have some trail capability. I'm adding 250lbs ea fr and rr with a 30gal aux tank and bumper/winch, and then planning to haul toys like inflatable kayaks and mtn bikes while towing. I'm starting with the AEV kit, then considering things like maybe PW radius arms for better flex, and a Thuren/Carli torsion sway bar. I figure that gets me in a decent place suspension-wise, and better to spend on locker/traction aids beyond. Springs and shock options seem very limited and there's just not much info.

Really wish we could see data like compression curves for all the RAM OEM and aftermarket springs. So far, all I see are a few general references to some spring rates, but this is almost misleading. I've read that the '19-20 trucks have "progressive rate" coils, but have never seen it quantified. I agree overall that some intelligent spring design directed at our trucks carrying near max loads would be a great thing and a fairly big market. I don't know what we're missing that this isn't being addressed.
 

Halligan

Adventurer
both left and right are the same on mine but what I found strange is my power wagon fronts and rears have the same part number as a 2500 diesel coils off of a laramie, limited or longhorn. I thought they would be power wagon specific. So it is not the coils that give the higher payload on the other models.

That can't be accurate. A PW ride's much smoother then a diesel 2500. A PW with diesel springs would ride harder than the diesel actually would due to the reduced engine weight.
 

IdaSHO

IDACAMPER
Not necessarily.

All in, the differences as I recall between the 6.4 and the cummins equate to roughly 650#
So you are less than 400# additional per coil up front.

Id say OEM running the same coil is likely.
The diesel will simply have a slightly lower ride height.
 

jadmt

ignore button user
That can't be accurate. A PW ride's much smoother then a diesel 2500. A PW with diesel springs would ride harder than the diesel actually would due to the reduced engine weight.
the tags on my coils are 68091203AB for the rear coils and 68349071AA for the front. plug those part numbers in and see. Mine rides smooth as butter.
 

Halligan

Adventurer
I wonder why the diesel rides harder? The shocks maybe? I'm not trusting the information from a generic parts website as gospel. The only way to do it would have somebody with a Crew Cab diesel Laramie, Limted, or Longhorn confirm what spring part numbers they have for comparison (and that may differ if the truck has snow plow prep option). Or maybe run some appropriate VIN #'s through your dealer parts dept.
 

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