Fox 2.5 DSC Suspension - A Brief Overview, Procedure, and Review of Proper Suspension Setup

[H2OMAN]

yeap. bound to happen.
im planning to do PPF to minimize the pinstripes and possible damages

Probably a good idea.

 

[Daverous]

plan to wrap the truck. cause or pin stripes lol…… but for suspensions idk whst esle it needs … have new rear control arms by core 4x4…. dobinson hd springs … fox suspension
changed to maxx suspension for front sway bar…. cnt find the clunk sound for **** …

I had two clucks with parts you've mentioned.
My front maxx links kept loosening up at the sway bar side even when torqued to spec. Blue loctite and they've been good 1000 miles or so.
I had an annoying clunk I couldn't find in the rear. It was my core 4x4 sway bar links. Torqed to spec and wasn't enough apprantly. Had to go overboard and it stopped it. I've also heard about their rear control arms needing a good 200 ft/lb to get them settled. Well above the 130 or so I've seen elsewhere.
Dobson uses single rate springs, right? I got a little clang out of my Clayton springs before isolators were installed as well. Maybe worth a look?

 

[ayoslickxd]

I had two clucks with parts you've mentioned.
My front maxx links kept loosening up at the sway bar side even when torqued to spec. Blue loctite and they've been good 1000 miles or so.
I had an annoying clunk I couldn't find in the rear. It was my core 4x4 sway bar links. Torqed to spec and wasn't enough apprantly. Had to go overboard and it stopped it. I've also heard about their rear control arms needing a good 200 ft/lb to get them settled. Well above the 130 or so I've seen elsewhere.
Dobson uses single rate springs, right? I got a little clang out of my Clayton springs before isolators were installed as well. Maybe worth a look?

dam sounds like everything i had some issues with lol …. i guess when i get home i have some parts to play with

 

[boogielander]

plan to wrap the truck. cause or pin stripes lol…… but for suspensions idk whst esle it needs … have new rear control arms by core 4x4…. dobinson hd springs … fox suspension
changed to maxx suspension for front sway bar…. cnt find the clunk sound for **** …

seems pretty solid plan! good luck with the clunk lol

 

[Rebel409]

hahaha well to be fair this weekend going in to and out of toquerville falls was the first time I wish i got more lift lol

scraped slider and exhaust tip because not enough ground clearance.

I'm considering going with a 4" lift on my rebel instead of the 3" (especially since I would only be setting it at 2.5"). I'm looking for a little more height than that. If you went with the 4" lift, how would you have done it?

 

[boogielander]

I'm considering going with a 4" lift on my rebel instead of the 3" (especially since I would only be setting it at 2.5"). I'm looking for a little more height than that. If you went with the 4" lift, how would you have done it?

custom king shocks.
the problem with most 4" lifts on the market right now are either utilizing spacers (which is a big no no for me) or just longer or heavier rated springs on coilovers to push it to 4", which sacrifices suspension travel and not at all a real 4" suspension lift.

to achieve 4" lift correctly with adequate travel, not only the suspension package needs to be custom, I'll also need extended UCA, LCA, tie rod, CV axle, and spindle because the geometry will be completely different. At that point, I might as well just make it into a +3 LT kit with fiberglass fenders and bypass shocks and ditch the sway bar. Now at that point, the suspension package will be more than adequate to tackle big whoops and g-outs that even raptors will have to slow down for.

 

[Andy08]

Did you add bump stops to the front?

 

[boogielander]

Did you add bump stops to the front?

not yet. i haven't hit the bump stops yet so i don't see the need to add them.
i do have tires rubbing the top of liner at somes though.

 

[SgtSlaughter]

Any fitment issues up front? I just dropped this setup in and my cv shaft is rubbing the bottom of the shock.

 

[boogielander]

Any fitment issues up front? I just dropped this setup in and my cv shaft is rubbing the bottom of the shock.

nope. no issue at all. you have pictures of everything?

edit: the only issue after 40k miles including maybe 20k of hard miles (high speed desert, crawling, high speed washboard, high speed million potholes on Alcan, Dempster, and Dalton) and additional ~300lb in/ under the cab my front end spring sagged. heavier rated springs going on next week.

edit 2:
did you put it in with preload exactly at where fox gave you? or did you adjust preload? did you do alignment after?

 

[SgtSlaughter]

nope. no issue at all. you have pictures of everything?

edit: the only issue after 40k miles including maybe 20k of hard miles (high speed desert, crawling, high speed washboard, high speed million potholes on Alcan, Dempster, and Dalton) and additional ~300lb in/ under the cab my front end spring sagged. heavier rated springs going on next week.

edit 2:
did you put it in with preload exactly at where fox gave you? or did you adjust preload? did you do alignment after?

Fox said the preload on theirs is the equivalent of a 2in lift on a stock Ram or about .5 in a rebel with the ecodiesel.

Running Fabtech UCA, I'm curious if those may be an issue. After alignment I'm -1.1 on the left and -1.7 right for caster and factory spec is like +3 to +5 according to them

 

[boogielander]

Fox said the preload on theirs is the equivalent of a 2in lift on a stock Ram or about .5 in a rebel with the ecodiesel.

Running Fabtech UCA, I'm curious if those may be an issue. After alignment I'm -1.1 on the left and -1.7 right for caster and factory spec is like +3 to +5 according to them

the only thing that i can think of for boot to touch the shock is improper angles, which is directly correlated to the UCA especially after alignment if your alignment guy knows what he's doing.

 

[boogielander]

March 2025 Update:
It's been over 2 years since I put the Fox 2.5 DSC in. During this time period, the truck has gained significant amount of weight that affects the suspension on both axles.
I have added full RCI Skid Plates, Sliders, fridge, more wiring, rear floor plate, rear floor cabinet, Ecoflow Delta 2 and add on battery, and I probably have gained some weight as well. THere's also at least one case of 24 bottles of water permanently residing in the cab, as well as some other things. In the bed, I have about 885lb constant sitting as well.

So, in total, my suspension was sitting at around 38" fender to ground all around, a whopping 2" difference than what it should be. In addition, I've been experiencing front end rub on top of fender when the front springs are compressed, and they compress too easily. That is telling me... the springs need some upgrade.

After some digging, here's the information I found:

• Fox utilizes 450lb spring in the front, which is find for an empty truck but inadequate for an overlanding truck. It also boggles my mind that Fox elect to go with 450lb springs instead of heavier springs, especially when King comes with at least 550lb springs. Sure, 450lb spring offers more travel than 550, but with 6" of droop and next to zero up travel that I had, a heavier rated spring should've came stock.
• Fox original spring dimension: 16"3" IDx450lb, made by Eibach.

So, here's what I did:

• Ordered 16"x3"IDx600lb spring from Eibach, though King also makes the same spring but coated blue.
• Completely disassemble the front to remove the coilovers and swapped out the springs.
  • This is really a royal pain in the butt. I will not share how this is done, as unique tools and methodology are needed. Hire a shop to do this, just not my shop because I don't want to mess with this ever again.
• Left the preload collar exactly as where it was with 450lb springs, as I wasn't sure what to expect.
• I also adjusted the preload collar on the driver side to compensate for the lean due to 33gallon fuel tank, the fat driver (aka me), the 24 bottles of water, and 7 gallons of water inside the bed.

This is the result.
This is by no means a complete finished project and is still a work in progress at this time.

• The front now sits at 41" fender to ground, or 25" fender to hub. Measuring from fender to hub nets me 3" BUT since this is a rebel, it equates to 4" gain compared to stock non ORG non Rebel.
• The Carli UCA angle is not right, angled down a bit as if I was drooping. The CV angle looks a bit over as well.
• I was hoping the springs will settle after my 60 miles commute today, but it doesn't seem like it did.
• The difference between front and rear fender to ground is 2" that is significant.
• The ride quality: definitely able to feel the 600lb springs making a difference, but with the preload set at previous setting, it does ride on the stiffer side.

Here's what's coming next:

• Cranking the preload in the front up to bring it down one inch at ride height.
• Swapping out the Carli springs for the rear for Clayton 2.5 HD Triple Rate springs, as my constant load is to much for what the Carli is rated for.

With the front adjusted and the rear corrected, I am expecting the truck to sit level after, with about 40" fender to ground all around and improved ride quality as well.

Here poses a question:
Why do people think 3.5 or 4" or more look good... it clearly doesn't.
why do some people think squatting look good... it clearly doesn't as well.

 

[boogielander]

April 5th Update:

• Cranked up preload, 1" preload driver side and 0.75" preload passenger side.
• Compare to before, 1.5" preload driver side and 1.25" passenger side, the ride height dropped 1".
• General ratio of 1:2 applies here.
  • 1:2 ratio = 1" turned at preload collar lead to 2" change in ride height. 0.5" turned at preload lead to 1" change in ride height.
  • No need to calculate for preload change with math, formulas, and equations.
• Do NOT try to do this with the shock sitting in vehicle. Shock removal is required. I tried to do passenger side on the truck (suspension at full droop, wheel removed) and the preload collar jumped and unseated. Had to force crank the collar all the way to the top to reseat itself. Luckily I did not damage any thread.

Passenger side

I ended up having to do the job twice because the first time I trusted math instead of my gut.


Result:
40" fender to ground in the front, 39" in the rear. At this point I don't want to mess with the rear, but I already paid for the springs and they are on the way.
I'll decide if I want to mess with the rear next week, since I don't know if the rear springs will actually raise the rear up or not.
I like how the Carli Rebel HD rear springs ride now, so the only reason to do the rear is to gain additional departure angle.

 

[Ready Go]

I'll decide if I want to mess with the rear next week, since I don't know if the rear springs will actually raise the rear up or not.
I like how the Carli Rebel HD rear springs ride now, so the only reason to do the rear is to gain additional departure angle.

Unfortunately, since the rear springs are on a solid axle, not an IRS strut, there isn't a way of preloading the rear springs to alter the "effective" spring rate like you can with a strut. The spring's rate is what it is and the only remedy for comfort is a spring swap.

I can understand your dilemma with swapping rear springs that have the right "ride" for you, but not height. Swapping springs means a different ride quality than your current setup..but your front springs are 100lb/in more, maybe a stiffer rear spring will actually balance the ride better anyways (along with the hopeful 1" height increas)

**I know I could mention rear spring spacers, but I know your answer will be "no way".

 

[boogielander]

Unfortunately, since the rear springs are on a solid axle, not an IRS strut, there isn't a way of preloading the rear springs to alter the "effective" spring rate like you can with a strut. The spring's rate is what it is and the only remedy for comfort is a spring swap.

I can understand your dilemma with swapping rear springs that have the right "ride" for you, but not height. Swapping springs means a different ride quality than your current setup..but your front springs are 100lb/in more, maybe a stiffer rear spring will actually balance the ride better anyways (along with the hopeful 1" height increas)

**I know I could mention rear spring spacers, but I know your answer will be "no way".

oh yeah hahaha
so the reason why i have rear springs on order is because:

• The Carli is more like an 1.5" spring than a full on 2 or 2.5" spring
• I am well over the spec (500lb) on the Carli Rebel HD, causing sagging.

I am hoping with the new springs (Clayton Offroad 2.5" HD Triple Rate Springs) will fix that issue because it is rated for 600+lb (on a JT but the bed weight difference shouldn't be that drastic) and it's 2.5" lift instead of 1.5" lift. The triple rate should also help as well, while Carli is only dual rate.

Funny thing is, I do have rear spring spacers sitting in the boxes. I was going to throw them in and call it a day because spacers are not as bad on solid axles compared to IFS, but ultimately I decided to go the heavier rated spring route lol

 

[boogielander]

April 5th Update:

• Cranked up preload, 1" preload driver side and 0.75" preload passenger side.
• Compare to before, 1.5" preload driver side and 1.25" passenger side, the ride height dropped 1".
• General ratio of 1:2 applies here.
  • 1:2 ratio = 1" turned at preload collar lead to 2" change in ride height. 0.5" turned at preload lead to 1" change in ride height.
  • No need to calculate for preload change with math, formulas, and equations.
• Do NOT try to do this with the shock sitting in vehicle. Shock removal is required. I tried to do passenger side on the truck (suspension at full droop, wheel removed) and the preload collar jumped and unseated. Had to force crank the collar all the way to the top to reseat itself. Luckily I did not damage any thread.

View attachment 199183
Passenger side
View attachment 199184
I ended up having to do the job twice because the first time I trusted math instead of my gut.

View attachment 199185
Result:
40" fender to ground in the front, 39" in the rear. At this point I don't want to mess with the rear, but I already paid for the springs and they are on the way.
I'll decide if I want to mess with the rear next week, since I don't know if the rear springs will actually raise the rear up or not.
I like how the Carli Rebel HD rear springs ride now, so the only reason to do the rear is to gain additional departure angle.

Took the truck on a long drive today, put about 60 miles on the clock with two double dips that I used to test my suspension.
The 600lb springs with current preload settings ride great on pavement most of the time. Only when pavement gets rough that the ride quality suffers a bit. I can probably turn the low speed compression knob down a few clicks, or even all the way to the least aggressive setting.
When going through the double dips that I simulate as whoops in the desert, the 600lb springs are very supportive. I sent through the first double dip at 30MPH to see how it felt, and it felt like the dip wasn't there at all. So I sent the truck through the second double dip at 50MPH. Normally, when I send it at 40MPH (the speed limit), I would rub the top of fender liner when landing with the DSC running my street setting (no rubbing with trail setting though). WIth the 600lb springs and DSC set at street setting and carrying more speed, there was no rub at all. The spring decompressed as I went through the dip, and compressed to stop the truck from sinking/ rubbing the fender liners as I return to level ground.

The steering and the front end ride quality was good, did not feel stiff at all. It was a bit more firm than 450lb springs that came with Fox, but it's the confidence inducing type of firmness. Compared to the previous preload setting that I had last week, the ride quality is fore sure an improvement.

Overall, aside from the work involved, I'm quite happy with the result of the front end "update" so far. The dirt portion will be tested next weekend when I lead a group run in Death Valley for 3 days.

 

[boogielander]

Today-
Out with the old (Carli Rebel HD)

In with the new (Clayton 2.5" HD Triple Rate) - 30 minutes job:

Don't mind the surface rust... that's what happens when averaging 60+ on wet Dempster and Dalton and then a full day at Bonneville on the same trip can do. Nothing concerning just surface rust that doesn't look good but oh wells, it's a truck built to perform not to be hard parked at the mall to attract more guys.

The result:

40" fender to ground all around (measured on level ground) an 1.5" improvement in the front and an 1" improvement in the rear.
Ride quality test on Monday.

I will say though, these should ride more firmer than Carli and shouldn't settle any more than it already is, judging by how much more strength it required 2 people to get them in without unbolting the rear arms (only the lower shock mount and sway bar were unbolted) Carli HD are already a PITA to get in and get out, these are even worse.
There's absolutely nothing wrong with Carli HD rears. The ride quality WAS GREAT and it provided A LOT OF DROOP. Even though they arrived on Monday, I was on the fence about swapping the Carli's out all week even until this morning. What finally pushed me over was seeing that 1" difference between front and rear, and knowing that the 800s lb of constant weight will not go anywhere. I mean, I could probably just remove all the stuff I brought to Alaska and Arctic Ocean from August and September, but I'm too lazy to do that everytime I go out to play.
So far, I am quite happy with the additional $700s in springs (of course, I didn't pay that much) despite the headache I had with the front.

 

[boogielander]

Alright so some comparison in the levelness:


This is when the truck had 600lb springs in the front and old Carli Rebel HD springs in the rear.
It is subtle, but the front is sitting higher than the rear due to weight. Tape measurement tells me 1" difference.

Using Photoshop when I was drawing the line, the yellow line (pinch weld to pinch weld) is about 0.37 degrees off, and green line (fender to fender) is about 0.1 degree off. This is after I have turned and cropped the image for the wheels to be flat (the light blue line) Red line represents the top of tire to top of tire, which is flat, same as the bottom (light blue)


This is when the truck has 600lb springs in the front and Clayton 2.5" HD Triple Rate in the back, with my constant load of about 880lb.

Using photoshop with the photo adjusted to level, it can be seen that the green (top line - fender to fender) sits at perfect level with 0 degree, red line (top of tire) also sits at perfect level with 0 degree. The yellow line (bottom - pinch weld to pinch weld) is also at 0 degree.

Conclusion:
With 600lb springs in the front, I regained my desired ride height with all the stuff I have installed inside the cab. Without touching the rear, I'd have a height difference of 1" between front and rear. Utilizing the Clayton 2.5" HD Triple Rate springs, I am able to compensate for the constant 880+lb in the bed and bring the truck back to leveled ride height.

This concludes the ride height portion of the upgrade. More testing will need to be done for the ride quality.

 

[boogielander]

Forgot to update this:


Took the truck to Death Valley in Mid April to tackle Owlshead Mountains and visit Racetrack Playa in a weekend trip.
A few big dips and jump points on the trail heading into Owlshead, and trail surface was rough in a few areas due to the flood in previous years.

Biggest difference I've experienced is that I no longer need to crank high speed adjuster to full stiffness on the trail anymore. Backing it down to click 5 (middle) improved the ride quality a lot. I think this is due to my unfamiliarity of the trail and terrain, as well as the 55MPH speed limit posted on Google Map, that prevented me from going full out.
Going through the dips and whoops felt a lot better, as I did not experience any bottoming out. However, sometimes it felt like I was about to catch air (aka, when the truck was still going up vertically) something grabbed from underneath and abruptly end the up motion and immediately start the downward motion. I think this is due to the piston valving unable to keep up with the shock, and this can only be resolved through revalving.

I left the rear adjusters exactly how it was before, and with the Clayton springs, the rear felt a lot more firm. It no longer feel plushy when the shocks were pushed. This is fine though, as the rear still felt controlled and I was able to put power down a lot more easily.


Between Owlshead and Badwater Basin there was a section of the trail completely covered by very fine sand originated from nearby dunes, and we had to slow down because it was hard to see the trail surface at times.
I maintained 30MPH in these sections and went through some dips and whoops. With the lowered ride height in 450lb springs, I'd rubbed the front skid in the sand for sure, but with the 600lb springs, I did not touch the skid on anything nor I dragged anything on the ground. It was a very enjoyable ride, aside from not being able to see the surface.


I was able to go at a faster pace heading into and out of Teakettle Junction, because I am familiar with this trail and it is more graded than Owlshead.
Going faster eliminated some of the uncomfortableness of rough section, as the suspension was able to stretch its legs. Took a few bumps going full speed, but the truck still felt controlled.
The section outside of Racetrack Playa was very washboardy, and there was nothing I could do. Doesn't matter how fast or how slow I go, the truck vibrated like crazy and that was the case for everyone in our group.
How fast did we go? Google said it takes about an hour to complete this 20 mile trail. We did it in 20 minutes.


Overall, as far as spring rate and ride height is concerned, I think I've reached the optimal point.
Sure, I probably could've went with 500 or 550lb springs and adjust the preload accordingly to get a more plushy ride in the front while retaining the DSC settings that I've been using, but I honestly don't know if that would achieve better results when going through the same whoops where I felt like the pistons were not keeping up. The gained ride height does help clearance a bit, as well as leaving more room for the shocks to compress to prevent bottoming out.

So far, I'm happy with the new springs that I've chosen. Perhaps I should play with the DSC knobs next time I'm out to see if I can further improve the ride quality.