spring rate question

[drowzyGX]

Hey Y'all,

I can't figure out if I have:

• the wrong preload
• the wrong spring
• both

I have icon 58645 coilovers and with the HD 700 lb springs with the basic 52700 springs in the rear on a 2004 GX470 with KDSS. The second and third row passenger seats are gone. They have been replaced with a set of plywood drawers that run from behind the driver and passenger seat to the rear door. I think this is roughly net-zero weight change. My tires are 265/70/17 on stock wheels.

My ride height, or center of hub to fender, measurements are:

• front driver: 23 3/4" (full droop: 25 1/2", preload: 3/4")
• front passenger: 23 1/2" (full droop: 25 1/2", preload: 5/8")
• rear driver: 24"
• read passenger: 23 1/2"

full extension / full droop, I have less than 2" of down travel, which I know is not good. I believe I'm also roughly 3" above factory hub-fender measurements.

Desired Outcome

• proper droop of at least 2" up front
• less than 3" of lift
• positive rake when unloaded, flat or minimally negative rake when loaded

I have the following mods that add weight up front:

• Lil B's front bumper: 115 lbs
• Apex Badlands 12K winch with synthetic line: 70 lbs
• RCI aluminum skid plates: 30 lbs (can't find exact weight for the front plate, but that seems right based on feel)
• White knuckle off-road sliders: 110 lbs (not sure how much of that is on the front coilovers)

Option 1
I can increase preload in the front. However, after 1/4" I'm at even rake. This means I'll be sagging when loaded out for a camping trip. This will further increase my hub to fender measurements, and that really isn't my goal. Bad option IMO.

Option 2
I can get heavier springs for the back. Then increase preload up front. This nets me the desired down travel while also keeping the rake I want. However, it means even more lift, and I really don't want that. I don't think the Icon stage 2 kit components are designed for much more lift than what I currently have.

Option 3
Swap back to the original Icon springs, and tune preload until I have the droop and rake I want.

I think option 3 is the way to go, but everything I read online seemed to indicate the added weight from the bumper and winch required heavier springs. The heavier rate springs have been on for a year now. So I know they aren't going to settle any more.

Am I missing something here? Is it as simple as, "I tried the heavier coil over springs, and it was the wrong move"? What are y'all's thoughts? Would love feedback so I can think this through carefully.

 

[HomersCanyonero]

Hey Y'all,

I can't figure out if I have:

• the wrong preload
• the wrong spring
• both

I have icon 58645 coilovers and with the HD 700 lb springs with the basic 52700 springs in the rear on a 2004 GX470 with KDSS. The second and third row passenger seats are gone. They have been replaced with a set of plywood drawers that run from behind the driver and passenger seat to the rear door. I think this is roughly net-zero weight change. My tires are 265/70/17 on stock wheels.

My ride height, or center of hub to fender, measurements are:

• front driver: 23 3/4" (full droop: 25 1/2", preload: 3/4")
• front passenger: 23 1/2" (full droop: 25 1/2", preload: 5/8")
• rear driver: 24"
• read passenger: 23 1/2"

full extension / full droop, I have less than 2" of down travel, which I know is not good. I believe I'm also roughly 3" above factory hub-fender measurements.

Desired Outcome

• proper droop of at least 2" up front
• less than 3" of lift
• positive rake when unloaded, flat or minimally negative rake when loaded

I have the following mods that add weight up front:

• Lil B's front bumper: 115 lbs
• Apex Badlands 12K winch with synthetic line: 70 lbs
• RCI aluminum skid plates: 30 lbs (can't find exact weight for the front plate, but that seems right based on feel)
• White knuckle off-road sliders: 110 lbs (not sure how much of that is on the front coilovers)

Option 1
I can increase preload in the front. However, after 1/4" I'm at even rake. This means I'll be sagging when loaded out for a camping trip. This will further increase my hub to fender measurements, and that really isn't my goal. Bad option IMO.

Option 2
I can get heavier springs for the back. Then increase preload up front. This nets me the desired down travel while also keeping the rake I want. However, it means even more lift, and I really don't want that. I don't think the Icon stage 2 kit components are designed for much more lift than what I currently have.

Option 3
Swap back to the original Icon springs, and tune preload until I have the droop and rake I want.

I think option 3 is the way to go, but everything I read online seemed to indicate the added weight from the bumper and winch required heavier springs. The heavier rate springs have been on for a year now. So I know they aren't going to settle any more.

Am I missing something here? Is it as simple as, "I tried the heavier coil over springs, and it was the wrong move"? What are y'all's thoughts? Would love feedback so I can think this through carefully.

I have a similar setup in the front with restless Offroad hybrid front bumper, OVS scar 10s winch, skid plates, OPOR rock sliders…I’m running Bilstein 6112 (2.6” thick shocks) with 700 lbf/in coils.

The difference is that I setup my front coilovers at a circlip/preload that gives me 22.625” (22 5/8”) hub ti fender or about 2 3/8” lift from stock (20 1/4” stock hub to fender). No front sway bar and I get a good droop upfront.

Rear is a problem with long travel icon 56550 and Dobinson c59-701V. I have more lift than I want in the rear unless I’m fully loaded for a trip.

I have drawers on passenger side only with tools, parts, a fridge and a bluetti power station plus a swingout tire carrier

If I’m half loaded, I have too much of a rake and if I’m fully loaded I’m at a good rake.

Anyways, try lowering the front by 1” and adjust the back as needed by getting a rear coil that fits your weight needs.

I have a HD Nolathane rear sway bar to balance out the front articulation and reduce sawing in front.

 

[HomersCanyonero]

By the way, the rear is always a problem due to changing loads and personal preference for ride quality and rake level.

 

[Rednexus]

Since those Icon coilovers are threaded, I'd personally start by reducing the front ride height by around 1/2" (1/4" increase in height on the top coil spring seat). That would net you 1/2" more droop and about 1/2"-3/4" rake. This assumes it rides OK and is not overly stiff in the front with those coils. If you want a bit more rake, I'd then add some 1/2" coil spacers in the rear, which would get you to right around 1/2" of rake. That should be pretty easy and close to free. Then you can see how you like it and either fine-tune it more or look at swapping springs (I have Dobinsons C59-677Vs in the back and like them a lot, but they'd probably lift it more than you are looking for).

Another cheap/easy option you could consider are aux airbags inside the coils (Firestone bags are around $120). You can then easily add air to get stiffness/ride height back when loaded up. I keep mine at 5 psi unloaded and run them as high as 30 psi when towing.

 

[HomersCanyonero]

Since those Icon coilovers are threaded, I'd personally start by reducing the front ride height by around 1/2" (1/4" increase in height on the top coil spring seat). That would net you 1/2" more droop and about 1/2"-3/4" rake. This assumes it rides OK and is not overly stiff in the front with those coils. If you want a bit more rake, I'd then add some 1/2" coil spacers in the rear, which would get you to right around 1/2" of rake. That should be pretty easy and close to free. Then you can see how you like it and either fine-tune it more or look at swapping springs (I have Dobinsons C59-677Vs in the back and like them a lot, but they'd probably lift it more than you are looking for).

Another cheap/easy option you could consider are aux airbags inside the coils (Firestone bags are around $120). You can then easily add air to get stiffness/ride height back when loaded up. I keep mine at 5 psi unloaded and run them as high as 30 psi when towing.

I read that he also has a 3” lift in rear based on his hub to fender measurement of 24”, so he’s already too high in the rear on one side.

Maybe @drowzyGX needs to fix the kdss lean as well, but that’s a separate issue.

For now, lower the front

 

[drowzyGX]

I’m not having any issues with the rear. No desire to change anything there. The bolt on track bar correction piece from Dr KDSS got that all leveled out. The truck is mostly fully loaded. All of my tools and recovery gear are in a storage cubby that sits exactly where the second row seat used to be. When I go on a trip, the weight is coming from the addition of my fully-loaded cooler.

It turns out I’m just not very bright: decreasing preload in the front will net me more droop and decrease the lift height. That’s exactly what I want.

Looks like the best option to try is decreasing preload. Will see if I can get another decrease of 1/2” to 3/4”. If so, that should get me the droop and rake I want.

If I can’t, I’m thinking the answer is lighter rate springs. @HomersCanyonero you said you’re at 22 5/8” for hub to fender. If I reduce to 0” preload, I’m at 23”. That’s the only reason I’m thinking maybe I don’t need the HD springs?

 

[Rednexus]

I bet you can easily drop it 3/4" in the front since so much of the Icon coilover body is threaded. When I did this on my Foam Cell Pros I cleaned the shock body and lubricated it in penetrating oil to make it easier to turn with the Ironman spanner wrench. Since you are going down it should be easier than what I was doing (going up).

The shock has a 2:1 ratio with the ride height, so if you want to drop it 3/4" you'll need to move the top mount up 3/8". On my rig I measured the exposed threaded length on the shock, calculated what it needed to be to get the ride height I wanted, and adjusted it to that. The ride height came out perfect using that method.

 

[drowzyGX]

Awesome - that confirms I’ve at least been adjusting preload correctly (by measuring the length of exposed threads). I forgot about the 2-1 rule.

You’re right. I should definitely be able to get 3/4” lower in the front. I bought the icon spanner wrench with the lift kit. A little pb blaster, and I haven’t had too much trouble adjusting preload with the front end up on jack stands.

 

[HomersCanyonero]

Front coilovers is 2:1 ratio as @Rednexus said, so aim for a 22.75” hub to fender in the front and that’s a good 2.5” lift in the front.

And the question will be is that too
much rake for you since the rear will be at around 24”?

 

[HomersCanyonero]

And one more thing, I don’t have kdss, but I have the infamous Toyota lean where I’m lower on the driver side due to battery, driver, and gas tank.

So, I have my driver side front coilover at the 5th circlip from the bottom and the passenger side coilover on the 4th circlip from the bottom.

Moral of the story is you don’t have to have exactly the same preload on your coilovers…you can adjust for lean at least in my non kdss model.

 

[drowzyGX]

Well, as usual, this forum was incredibly helpful and led me to the right answer.

Decreased the coilover preload today, and my new hub to fender measurements up front are 22 3/4”.

I’m at 3” of droop and a bit over 2” of lift. Drove around the city today and slammed some potholes - feels much better.

 

[HomersCanyonero]

Well, as usual, this forum was incredibly helpful and led me to the right answer.

Decreased the coilover preload today, and my new hub to fender measurements up front are 22 3/4”.

I’m at 3” of droop and a bit over 2” of lift. Drove around the city today and slammed some potholes - feels much better.

How your rear rake? It’s acceptable to your liking?

 

[drowzyGX]

not as much rake as I'd like, but the ride quality is much improved. i think i'd need to toss heavier duty springs in the back to get the rake i want. happy with how it's riding.

my icon kit has about 35K miles on it. figure it will be time for a rebuild or new suspension in the next year or so. when that time comes, i'm gonna ditch kdss and get the weld-on kit for adding non-kdss swaybars. i think that will get me exactly what i want, and no more fussing with the kdss system.