Reaching out to those doing their own shock tuning?

[CrazyCooter]

So I got the build installed with the Clayton 2.5" diesel springs, Fox 2.5's, BFG KO2 37's, Method 705 +25mm, and EVO/King air bumps (sumo springs already installed).

Looks like I'm going to be good on clearance. (they didn't adjust the track bars correctly, so I have a little rub on one side on the lower front control arm, but once I get that adjusted I' think I'll be good).

FYI, the diesel specific springs gave me a little more than 4" lift in the front vs. saggy stock springs. I got about 3" lift in the rear vs. stock, (all measurements with empty truck, Smart Cap installed). So I don't think I'll have any problem in the future putting on a winch+bumper. And with the 37's included, I've gained 5.5" total up front! Man, this is a tall truck now (I see why you did the power steps).

I'm dialing in the ride with the Fox shocks. Currently running at about 5 or 6 for high speed damping, and the same for low speed damping for street driving+empty truck. When hooking up the #4k trailer, I had a lot of bounce/bobble at those settings, so dialed it up to 9 on high-speed damper, and that eliminated the bounce.

So far, pretty good. It is quite a bit stiffer than stock. No more plush ride. But I can hit potholes I had to be careful to avoid before. And when towing, my rear only drops about 3/4" to 1" to engage the sumos, so just about perfect.

Thanks for all your info on this thread. Helped me dial in this build pretty well!

Ready for MOAB!

Do you find the rear on the stiff side from small bumps with quick shaft speed while towing heavier? Like expansion joints on a concrete highway just shake your insides? I noted this with the shocks as shipped and I still had it with my tunes........I had an idea that was implemented this week, but have yet to test the towing part of it.

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[PackMule]

Do you find the rear on the stiff side from small bumps with quick shaft speed while towing heavier? Like expansion joints on a concrete highway just shake your insides? I noted this with the shocks as shipped and I still had it with my tunes........I had an idea that was implemented this week, but have yet to test the towing part of it.

Yes I have. I'm trying to figure that out.... however I found that my shop inflated my tires to about 40psi to start out with, so I'm no sure if it was the shocks or the overinflation of my new 37's. I only had about 2 days to mess with this before strapping on the trailer and heading to Moab.

After a week in Moab (which was a LOT of fun), I see exactly what your are talking about on this -thread,... e.g. this setup has a ton of potential that is not tapped at all, out-of-the-box.

Firstly, I like the Clayton springs... even the 225lb front 2.5" springs. At first I was running into what you experienced above... e.g. stiff on small bumps, wondering if they were too stiff and contemplating maybe switching to the gasser springs. But after wheeling it, I'm finding I'm still hitting the jounce bumps frequently... even with no winch/heavy bumper. So I don't think its the springs being too stiff. I'm going to stick with these rather than the gasser 2.5's. But I think I'm needing to work on tuning other components.

The Fox Performance/Elite shocks, being that they are manufactured for JL's to JT's to EcoD JT's... are WAAAAAY under damped for the JT EcoD. If I run them at 9 (of 9) on the high speed damping, and 9 of 12 on the slow-speed damping, it is just barely OK, ... especially for rock crawling and towing. So I'm going to have to do a custom tune on them. Not sure I'll to do it myself like you, or hit up Accutune or Fox when I'm down south this Oct.

My Icon (King) jounce bumps are at about 100-110 psi, ... might need to run them a bit higher. When wheeling I hear them "click" when they are engaging, but not feeling much resistance. I don't know if I'm bottoming them out in what I've done... but I didn't push them near like I'm seeing you do in your vid. clips. I just don't have the shock damping to do what you are doing.

All the above considered, the rig configured as is, even with these shortcomings, is at least 200% better than stock!!! I did Fins N' Things, and Hells Revenge (not including Hells Gate, Escalator, or any bathtubs, ... it is my DD after all), and had a blast. I think I !hit my rocker rails 3 times. Breakover angle was not much of an issue. As for departure angle, my hitch-mount skid was well used!

 

[CrazyCooter]

Yes I have. I'm trying to figure that out.... however I found that my shop inflated my tires to about 40psi to start out with, so I'm no sure if it was the shocks or the overinflation of my new 37's. I only had about 2 days to mess with this before strapping on the trailer and heading to Moab.

After a week in Moab (which was a LOT of fun), I see exactly what your are talking about on this -thread,... e.g. this setup has a ton of potential that is not tapped at all, out-of-the-box.

Firstly, I like the Clayton springs... even the 225lb front 2.5" springs. At first I was running into what you experienced above... e.g. stiff on small bumps, wondering if they were too stiff and contemplating maybe switching to the gasser springs. But after wheeling it, I'm finding I'm still hitting the jounce bumps frequently... even with no winch/heavy bumper. So I don't think its the springs being too stiff. I'm going to stick with these rather than the gasser 2.5's. But I think I'm needing to work on tuning other components.

The Fox Performance/Elite shocks, being that they are manufactured for JL's to JT's to EcoD JT's... are WAAAAAY under damped for the JT EcoD. If I run them at 9 (of 9) on the high speed damping, and 9 of 12 on the slow-speed damping, it is just barely OK, ... especially for rock crawling and towing. So I'm going to have to do a custom tune on them. Not sure I'll to do it myself like you, or hit up Accutune or Fox when I'm down south this Oct.

My Icon (King) jounce bumps are at about 100-110 psi, ... might need to run them a bit higher. When wheeling I hear them "click" when they are engaging, but not feeling much resistance. I don't know if I'm bottoming them out in what I've done... but I didn't push them near like I'm seeing you do in your vid. clips. I just don't have the shock damping to do what you are doing.

All the above considered, the rig configured as is, even with these shortcomings, is at least 200% better than stock!!! I did Fins N' Things, and Hells Revenge (not including Hells Gate, Escalator, or any bathtubs, ... it is my DD after all), and had a blast. I think I !hit my rocker rails 3 times. Breakover angle was not much of an issue. As for departure angle, my hitch-mount skid was well used!

YES, the shocks are WAY underdamped when I'm swapping out .006-.008" shims they supply for .012-.020's and cut the free bleed in half? They missed the mark by a continent!

Good to have that feedback on the harshness......I know this isn't isolated to my setup then! It's definitly worse with higher air pressures.......I ran 35psi over to the coast with my GeoPro and only 27psi on the way home with a notable difference. My self educated guess/opinion (Seat of the pants since I don't own a dyno yet) is the shims at the top of the stack are hitting the rate plate spiking the damping at high shaft speed moments.

My test is to add some .700 shims to the top of the stack so the transition isn't so abrupt. I still need to hook up to a heavy tongue trailer an test, because with our light trucks, I don't think we can get a 2.5" shock to flex that stack otherwise. I really think I 2.5" shock is overkill for what most people are doing and I even sometimes think they are overkill for me?

Every tuner I have talked to didn't understand why the need for the .700 shims.........Does this mean they don't "get it" and I'm a genius? Time and testing will tell! Wouldn't be the first time I had to redo the expert's job because it didn't work right.......

What about any change after you aired down? I was experiencing a severe loss of low speed damping when I dropped the air pressure down to say 16-18psi. You feel the same?

Air bumps.......I'm running 250psi in my fronts and 200psi rear. The front thud pretty good and I plan on going to 300psi next.

I plan on getting the 3.5" diesel springs next because the 3.5 gas springs (188lb) were such a MAJOR improvement over my Evo plush springs (est. 120-125lb) in keeping me from slamming the bumps. That 15% increase in rate and .5" increase in bump gap will make it pure heaven I think!

I don't normally drive like you see in that last clip, but I do it for testing so when something sneaks up on me, the truck will soak it up! I find an obstacle that makes the chassis do something I don't like and drive over it a few times while making adjustments. Also just ordered a phone tripod so that I can take some quality videos.........

 

[PackMule]

YES, the shocks are WAY underdamped when I'm swapping out .006-.008" shims they supply for .012-.020's and cut the free bleed in half? They missed the mark by a continent!

Good to have that feedback on the harshness......I know this isn't isolated to my setup then! It's definitly worse with higher air pressures.......I ran 35psi over to the coast with my GeoPro and only 27psi on the way home with a notable difference. My self educated guess/opinion (Seat of the pants since I don't own a dyno yet) is the shims at the top of the stack are hitting the rate plate spiking the damping at high shaft speed moments.

My test is to add some .700 shims to the top of the stack so the transition isn't so abrupt. I still need to hook up to a heavy tongue trailer an test, because with our light trucks, I don't think we can get a 2.5" shock to flex that stack otherwise. I really think I 2.5" shock is overkill for what most people are doing and I even sometimes think they are overkill for me?

Every tuner I have talked to didn't understand why the need for the .700 shims.........Does this mean they don't "get it" and I'm a genius? Time and testing will tell! Wouldn't be the first time I had to redo the expert's job because it didn't work right.......

What about any change after you aired down? I was experiencing a severe loss of low speed damping when I dropped the air pressure down to say 16-18psi. You feel the same?

Air bumps.......I'm running 250psi in my fronts and 200psi rear. The front thud pretty good and I plan on going to 300psi next.

I plan on getting the 3.5" diesel springs next because the 3.5 gas springs (188lb) were such a MAJOR improvement over my Evo plush springs (est. 120-125lb) in keeping me from slamming the bumps. That 15% increase in rate and .5" increase in bump gap will make it pure heaven I think!

I don't normally drive like you see in that last clip, but I do it for testing so when something sneaks up on me, the truck will soak it up! I find an obstacle that makes the chassis do something I don't like and drive over it a few times while making adjustments. Also just ordered a phone tripod so that I can take some quality videos.........

Just to say I'm limited in my use-cases so far,... but I'll say the rig unloaded ran pretty nice at about 15 psi on the 37's and 9's on the damping! Could do Moab streets, or Fins N' Things!

Also, I don't have my load-leveling hitch set right yet. I didn't have enough time between lift installation and multi-trips between the RV shop to break loose the bolts on my hitch, and then 2hr drives back to the CAT scale in order to dial in my tongue wt. As a result, I had to eyeball it for one adjustment, and as a result, I weighed after "eyeballing" and figured I'm probably running north of 700lb tongue wt. for my 4700lb lb trailer. :-( So that is giving me too much soft bobble, even at 9 on the damping, but might be also artificially smoothing out the expansion joint bounce a bit.

When I'm home this week, I'll let you know how it performs unloaded with lower PSI settings... probably in the 30 psi range.

 

[CrazyCooter]

Just to say I'm limited in my use-cases so far,... but I'll say the rig unloaded ran pretty nice at about 15 psi on the 37's and 9's on the damping! Could do Moab streets, or Fins N' Things!

Also, I don't have my load-leveling hitch set right yet. I didn't have enough time between lift installation and multi-trips between the RV shop to break loose the bolts on my hitch, and then 2hr drives back to the CAT scale in order to dial in my tongue wt. As a result, I had to eyeball it for one adjustment, and as a result, I weighed after "eyeballing" and figured I'm probably running north of 700lb tongue wt. for my 4700lb lb trailer. :-( So that is giving me too much soft bobble, even at 9 on the damping, but might be also artificially smoothing out the expansion joint bounce a bit.

When I'm home this week, I'll let you know how it performs unloaded with lower PSI settings... probably in the 30 psi range.

Did you put air bags in the rear springs? I found that they do help level stuff out too.

 

[PackMule]

Did you put air bags in the rear springs? I found that they do help level stuff out too.

Sumo springs... the 500lb set, ... not the 1000lb set. I put these on before the lift/shock upgrade. Really liked how they helped out on the heavy loads, as well as cutting down on body roll.

 

[CrazyCooter]

Sumo springs... the 500lb set, ... not the 1000lb set. I put these on before the lift/shock upgrade. Really liked how they helped out on the heavy loads, as well as cutting down on body roll.

That could be where your rigidity is coming from then. Shocks aren't going to come unto play much when you are riding in the Sumos. They could also be acting together amplifying the problem? I know they are polyfoam, but its still a semi rigid connection. Remember those Sumos will also transfer cross chassis weight to the front and make you hit the air bumps more frequently. They make a great progressive bump stop, but I'm not a fan of either Timbren or Sumos on off road vehicles.

Just 5psi in my air bags would wreak havoc on mine till I got the heavier front springs and even now I can feel them.

 

[Rusty PW]

Cooter, have question for you. What shock lengths front and rear would you do for a 2.5" or a 3.5" lift? I'm trying to get an idea on what i need.

 

[CrazyCooter]

Cooter, have question for you. What shock lengths front and rear would you do for a 2.5" or a 3.5" lift? I'm trying to get an idea on what i need.

I went with the longest shocks that the rear hoses 28.3" and front driveline could handle 28.5" for my planned 2"/.75" lift which came out at the Fox 3.5-4" fronts and 2-3" rears. I'm now at 3/2.5" lift and stay still work great. This is assuming you aren't going with bypass shocks

 

[Rusty PW]

The reason I asked. Is because I have a set of King 2.5 shocks off of my Power Wagon. They are custom tuned by Thuren, 2.5 valving. These have have all the bells and whistles. The rears are the short body long travel option. All have the stainless steel shafts. There's only 4,000 miles on them. I got over $4k in them. They measure 30.5" in length. Wondering if they would fit. To get King shocks now will take 8 to 10 months.

 

[CrazyCooter]

The reason I asked. Is because I have a set of King 2.5 shocks off of my Power Wagon. They are custom tuned by Thuren, 2.5 valving. These have have all the bells and whistles. The rears are the short body long travel option. All have the stainless steel shafts. There's only 4,000 miles on them. I got over $4k in them. They measure 30.5" in length. Wondering if they would fit. To get King shocks now will take 8 to 10 months.

If you are doing a 3.5+ lift with proper bump spacing, brake lines/extensions, and a front driveshaft I think you could pull it off without limit straps.

In the front, I'm bump stopped to fit 37's no rub on a Rubi and I have 3/4-1" shaft left. Bump 1" more to fit 38's and you could be good.

In the rear I have much more shaft showing and if you use a multi rate spring with a long free length, your spring wont drop out.

I'd say get your compressed length numbers and start measuring thing out. The sleeves in those rear shocks should fit the JT bolts/brackets. The front will require different spacers for sure, but those could either be made or aquired since King makes shocks for JT's.

I have work with Don and the crew for years, so I'd be willing to share my setting if it helps them get a usable base tune OR I mat be doing some tuning for a client of mine that has an Evo Enforcer lift w/ Kings that we did a couple of years back and that could be a starting point?

I'm sure you could get big $$$ for those shocks with the wait IF you could get replacements for yours? Thuren is one of the biggest names in Dodge/Ram trucks if not THE biggest. Funny I found some threads from 20 years ago from Don asking for help from the forum experts on valving changes........Look where he is now.......Took it next level!

I'm considering buying that shock dyno if my new hire works out like I hope, that could free me up for other more technical ventures. I don't see how anyone that doesn't own and drive a certain vehicle daily could give you the best tune for the conditions a person operates in. Wife and I are already talking about her next vehicle JL, Bronco, 4 Runner etc.......That could be offering #2?

 

[kgc]

I did a revalve on my rear shocks this past weekend. @CrazyCooter, thanks for sharing your charts. I ended up doing a Fox #90 rebound tune (all .015 shims) and mimicked your compression tune on page 7. So far it is 1000x better but I still need to give it a proper shakedown in the desert.

I have the 3.6, so I'm not having the weight issues you are, and the fronts, which are the stock tune weren't terrible, although I do need to make some adjustments now, as I usually have the LSC all the way in and the HSC 1-2 clicks from closed. And I'm sure the stiffer rear tune will make the front feel even softer.

My rear shocks were purchased and tuned by Accutune. I was surprised that this tune actually looks to be lighter than stock (stock being what @CrazyCooter listed on his spreadsheet), with the rebound being especially light (which has been problematic at mid-high speed as the back end really has liked to 'buck'). The compression tune was also much lighter than stock on the high-speed size. The low speed side was the same, with the addition of a 1.800x .010 'bleed shim' with ridges on the end. Aside from the free bleed, I don't know what if the bleed shim contributes to spring rate of the shim stack? I attached a photo of what came out - rebound stack on top, compression underneath.

I'm stoked on the change - the back end feels so much more 'settled' now - and am excited to improve the front, and make some additional incremental improvements to the rear.

 

[CrazyCooter]

I did a revalve on my rear shocks this past weekend. @CrazyCooter, thanks for sharing your charts. I ended up doing a Fox #90 rebound tune (all .015 shims) and mimicked your compression tune on page 7. So far it is 1000x better but I still need to give it a proper shakedown in the desert.

I have the 3.6, so I'm not having the weight issues you are, and the fronts, which are the stock tune weren't terrible, although I do need to make some adjustments now, as I usually have the LSC all the way in and the HSC 1-2 clicks from closed. And I'm sure the stiffer rear tune will make the front feel even softer.

My rear shocks were purchased and tuned by Accutune. I was surprised that this tune actually looks to be lighter than stock (stock being what @CrazyCooter listed on his spreadsheet), with the rebound being especially light (which has been problematic at mid-high speed as the back end really has liked to 'buck'). The compression tune was also much lighter than stock on the high-speed size. The low speed side was the same, with the addition of a 1.800x .010 'bleed shim' with ridges on the end. Aside from the free bleed, I don't know what if the bleed shim contributes to spring rate of the shim stack? I attached a photo of what came out - rebound stack on top, compression underneath.

I'm stoked on the change - the back end feels so much more 'settled' now - and am excited to improve the front, and make some additional incremental improvements to the rear.

This is AWESOME! Glad to help someone else out.......

What springs are you running?

I'm running (3) 1.6 x .015's, 1.425 X .012, 1.100 x .010 (flutter), then .015's the rest of the way right now on the rebound. Trying to get it firm on the road and compliant off road.

I also ordered 4 port bleeds to firm it up at low trail speeds and highway. I have to assume that .008 think bleed shim pretty much does nothing to the stack firmenss since it takes (3) .012's to equal a .020" At the same time, I have to assume the 1.8" shim above it has a big effect on the bleed since it would hold it closed? You know you can also get rebound bleeds too?

I'm on tune #15 right now!

I also see 2 flutters on the compression stack in your pic? I am already going there in my head as I close in on this. The tuning will never be done!

PM me some contact info and we can bounce ideas if you want. I've been nagging @Glamisfan and he would probably like to have a break......

 

[CrazyCooter]

Here's where I'm at right now........ I'm trying to get my rear tires to follow the ground like the front does in that video while still towing well.

 

[kgc]

This is AWESOME! Glad to help someone else out.......

What springs are you running?

I'm running (3) 1.6 x .015's, 1.425 X .012, 1.100 x .010 (flutter), then .015's the rest of the way right now on the rebound. Trying to get it firm on the road and compliant off road.

I also ordered 4 port bleeds to firm it up at low trail speeds and highway. I have to assume that .008 think bleed shim pretty much does nothing to the stack firmenss since it takes (3) .012's to equal a .020" At the same time, I have to assume the 1.8" shim above it has a big effect on the bleed since it would hold it closed? You know you can also get rebound bleeds too?

I'm on tune #15 right now!

I also see 2 flutters on the compression stack in your pic? I am already going there in my head as I close in on this. The tuning will never be done!

PM me some contact info and we can bounce ideas if you want. I've been nagging @Glamisfan and he would probably like to have a break......

I am running Rock Jock 2.5 springs in the rear, and Synergy 4" springs in the front. (both designed for gas engines) The synergy's are softer than I'd prefer but were the only springs I could find at the time with enough free length for my setup. I have the 4.5-6" shocks, 2" bumpstop spacers, and Fox air bumps up front. In the rear I am running a 1-⅛" bump stop spacer and the factory bumps. I should be getting 12" up front and 14" in the rear, and at rest I get very close to 6" of shock shaft showing front and rear, which means I'm pretty close to 50% uptravel (I know the rear leverage ratio changes with the shock's relative angle, but trig was my worst topic in math.

I don't think the compression stack in the picture is a true double flutter.... The last three shims are .7x.020, .8x.020 and .8x020, I think the .7 would be the base shim and none of them would flex at all - just spacing the stack away from the rate plate, no? I'll PM you more info on the stacks.

The rear of the truck is riding really well. Just a bit of a jolt at initial compression - like when hitting a speed hump at 20-25mph. I'm wondering if the adding the bleed shim back in would make a difference there.

It is so cool that you're on revalve #15 - your rebound stack looks crazy at first glance, but knowing you put in the time to get to that 3x 1.6x.015 setup makes me think that it is right!

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