Icon 2.5 revalve

I think my Icon's are in need of a re-valve and ?maybe? my front LCA bushings are in need of replacement. Truck wallows in the corners more than ever now, even with the stability bar back on.
Anyway, revalve planning, my 2.5" icon should currently have:
Compression stack: T ___ D

1. 0.015 _____ 0.925
2. 0.015 _______ 1.05
3. 0.015 _________ 1.175
4. 0.018 ___________ 1.3
5. 0.015 _____________ 1.425
6. 0.015 _______________ 1.55
7. 0.015 _____ 0.925
8. 0.015 _______________ 1.55
9. 0.015 _____ 0.925

total thickness 0.138

I think I want to switch to:

1. 0.018 ___________ 1.3
2. 0.012 _____ 0.925
3. 0.012 _________ 1.175
4. 0.015 ___________ 1.3
5. 0.018 _____________ 1.425
6. 0.010 _________ 1.175
7. 0.018 _______________ 1.55
8. 0.010 _____ 0.925
9. 0.010 _________ 1.175
10. 0.010 _______________ 1.55
11. 0.012 _____ 0.925

total thickness 0.145

What this should give me is: more digressive preload, resulting in better cornering stiffness, but also a smoother/bigger crossover step, with a second crossover shim after the main crossover, this should make the shock behave more digressively (stiffer) at low speeds, but then also more progressively (stiffer) at higher speeds. The digressive region of the curve should be an even shorter spike than the Icon valving, but with a pretty smooth, and also more extreme falloff in damping force, before ramping up more quickly than Icon's valving to be slightly stiffer at peak piston speeds. I'm not sure if the 1.3 shim after the fulcrum shim will do what I want it to do, it should serve as a "flexible backing shim" vs a rate plate, controlling the peak piston speed, I'm adding this shim under the assumption that the piston ports will not limit peak piston speed as they do in a conventional progressive shock.
Changing shock valving 'cause it will cost $300 and 12 hours vs buying a proper long travel setup, or even more/bypass shocks.
Feedback welcome.

 

Did you ever revalve the shocks with this 2x "flutter stack"? Also where did you get your valving shims for your Icons. They don't seem to sell them anywhere.

 

I was just asking folks this today

would love to know as well

 

I’m going to rip all four of my 2.5 remote resi off soon and rebuild and revalve them. I’ll bust out the good ol micrometer and measure the ID and OD (plus thickness of compressions shims) and report. I have many fox 2.5” shims on hand so we will see if they can be made to work...

I have extended travel 2.5s resi up front with 650lbs springs and 2.5s Resi in the rear on a 2018 4x4 4door. I love the “digressive” valving in them now for most situations. I run no sway bar so the lower speed stiffness is nice. Also medium speed is controlled and not too stiff. rollers are nice and firm with good bottom out control , when the suspension is fully drooped out then allowed to compress ( like a rolling jump) . The only complaint is high speed impacts are way too soft. I’m only going to add thicker shims on the high speed shims (the smaller diameter shims). Maybe even a rate plate washer, the same diameter as the smallest shim


From OP:

1. 0.015 _____ 0.925 (high speed shims)*
2. 0.015 _______ 1.05 (high speed shims)*
3. 0.015 _________ 1.175 (high speed shims)*
4. 0.018 ___________ 1.3
5. 0.015 _____________ 1.425
6. 0.015 _______________ 1.55
7. 0.015 _____ 0.925
8. 0.015 _______________ 1.55
9. 0.015 _____ 0.925

If this doesn’t work then I think it would be smarter to just add bump stops on all four corners for the “oh shit moments”.

 

Yeah so it took a while, working with Icon themselves, both for them to provide the details about what the shock had in it from them (in the 1st post) and to send the shims out, but I was able to buy all the parts from Icon.
From what I understand, all of their authorized dealers should also carry shims.

I did revavle to the 2x flutter stack. it really smooths out the performance on washboard type terrain and hitting single "big" objects like a 3" ridge or curb, depending on speed and loading, the back of the truck bucks hard on these with my current setup,

It also feels better in the corners, but I'm still not satisfied, sometimes the truck can "fall" into a corner as if it moved thru the digressive region of the damping curve like the flutter stack(s) opened. I'm working on adding a BMW roll bar to the truck to allow a push button swaybar disconnect.
On actual big hits, like getting the front end or the whole truck airborne feel better, the truck bottoms out still, but with how little air I'm getting, its not a jarring experience anymore. However, the rebound in this case is actually a bit under-damped, so the highspeed rebound shims might need a little thicker on the first highspeed shim too, I'll check if I still have the rebound stack written down.

That said, I probably need more travel to get the performance I want, I'm doing it all and stay in the 0-55mph range, but I'm not hitting rollers or dunes and airing the truck out much at all.
@2000prerunner23 if you are airing out and getting into "oh shit" moments often, get some hydro bumps for sure, or go LT.

Now the back end of my truck needs work, I run with about 500lbs of gear in the bed and empty, so I need something a lot more adjustable than the king shocks I'm running back there now. I'll also be running some air bags for a semi cab to make up the required spring rate when running loaded.
The truck is way to stiff back there unloaded and too soft loaded.

Right now I have a little over 8" front travel (ext coilovers + UCA) and a little over 10" rear travel (8pack leaf .5" longer shackle, 10" kings) (true vertical travel), I'm thinking with the next setup I should shoot for ~12" front and ~15" rear and run bypasses in the rear and a hydro bump up front... its an addiction lol

 

Goodness. I just want a revalve to make it smoother on the highway as a daily driver and more smooth similar as Kings (I know I know digressive vs progressive...)

Did Icon mail you the shims setup the way you want or did they basically just send you a bag of shims? I want a stack made and ready to drop in the shock when I rebuild and me not have to do anymore thinking or researching as I don't have the time.

(I honestly think if someone got good at this they could just sale stacks for when folks rebuild)

 

Accutune will sell you a pre-assembled stack that is pretty similar to what I made (I assume), a lot of his articles sold me on the dual flutter stack, as at the time I couldn't find evidence of anyone making a stack like that "just get bypasses" lol, Icon sent me all the shims I asked for.

The truck soaks a misaligned bridge joint on the highway much better now and has similar performance in the corners to before the re-valve.
I haven't had this stack on a shock dyno, but my goal was to get it to behave like it had a single bypass close to mid stroke.

 

For street use the Icon valving is good.

I use the truck for desert off roading out here in CA (Ocotillo Wells 99% of the time). I know the limits of the stock steering, spindle, lower arm mounts and total lack of a roll cage so nothing is super fast over deep woops (anything over 1' deep). 45 tops over mild sections and 35 over the "deeper" stuff (which a fully built truck wouldn't even slow down for). With that said you're right, at some point I need more travel. However, I think the front 9" can work well if valved correctly, but the rear end should definitely be at a minimum of 16" of travel (62" spring under soon). Rear travel is more important, especially rear up-travel. Even for the valving, most people can make a linear valving stack work great on the front end of a truck but it seems getting fancy with bypass shocks, bump stops, flutter stacks is more essential in the rear for trucks. There is not a lot of weight back there so base valving can be difficult to get right. Like I said bottom out control is way more vital in the rear for stability and comfort (don't want to flip end over end) but you also don't want a harsh ride that will snap your spine. Rebound adjustment is equally as important outback because you want the rear end to fall down as fast as possible so it will have more uptravel for the next woop or so.

Point is 9" of travel up front with 16-18" travel in the rear can be dialed in very well if you know what you are doing. Just look at class 7s race trucks.

I don't know. I'll just add a small diamer rate plate or double up the two smallest (high speed) shims. If that isn't enough it's either secondary bypass or bump stops. The rear will need 62" springs and some 14" bypasses.

When Icon sent you the shims what was the inner diameter of them (the hole size)? I want to see if I can just use my Fox shims.

 

already messaged accutune about a stack of shims yesterday and they said they don't carry Icon products....idk..?

 

Yes, they said the same to me. They seem to be fans of Fox/King, and who can blame them look how beautify the fox shocks look with all them shiny colors...


I wasn't sure about Icons coming from only working with Fox shocks on all my trucks and mtn bikes. But so far I love the seal design (which shows no leaking at all). Not even a little weeping which is normal. The outside wiper seals look much more beefy.



edit: What type of shock oil are you guys using? The $60 Icon oil? In the past I have used Fox blue oil (non race oil) before using cheap ATF fluid. ATF has similar viscosity and is made to thermo cycle. I'm just not sure about some of the additives/detergents they put in there. For these tinny 8" shocks not much oil is needed but if you are rebuild a lot then paying $60/gal can add up.

 

I'm at work still, so I don't have my garage notes handy.

Yeah I'm not desert pre-running by any means, I'm #broverlanding lol.
At least for the terrain I see most often, and what I use my truck for, a full on LT build isn't in the works.

If I were building a dezert truck, I would respect the 2:3 ratio most of the pro guys run in terms of front to rear travel, when I built IFS/IRS buggies we ran in that 2:3 range too, but it sounds like you know what you're doing and have a pretty good plan for your build!

 

Huh, well Fox shocks definitely have the best tech at the best price on market right now imo...

It was a bit annoying to get the shims from Icon, but you can.

I haven't worked with downsouth or filthy, but everyone says good things about them too.

 

I actually run the fox red stuff now. $65 for a gallon of the best fluid available? Yes please.

In the buggies, we used to run the blue, but that was before the JM92 red was easy to get, and then we switched to our own MR blend...

 

Mine leaked 3 months after buying them brand new and haven’t had time to rebuild them yet....it’s been awhile lol

 

Just FYI I contacted Icon and they are making me a customer stack.
Seems relatively cheap....like $40 for a revalve stack.

 

Should be here Wednesday

 

Just in case you wanted to compare
This is what was ordered based on what I told them I wanted

 

Did you end up getting this setup installed?

 

sorry not on here much. Actually just got back on to look up how to rebuild these since I have bought all the kits and oil a long time ago....just haven't had the time to rebuild them but I need to do it really bad!

 

Got the fronts off the truck and coils off. Hopefully can rebuild them in the next day or so and find somewhere with nitrogen to fill them back up.