Icon 52700 rear spring stiffness and further research

[usdmej]

after installing a lift kit for my 4runner (king shocks with stock front spring rate and icon 52700 rear springs) i've found the ride to be too stiff for day to day driving. my vehicle is stock weight with ~150 pounds of added gear (full length roof rack and sliders). when it's just me in the vehicle the ride is noticeably/annoyingly stiff. it only starts to get livable with at least 4 passengers total so i'm guessing ~400-500 pounds added weight. this is pretty consistent with Icon's recommended load range for the vehicle.

i'm currently considering either switching to a softer rear spring or adding some more full time weight to the vehicle. in the meantime, i've compiled a list of available rear springs and their spring rates that i've gotten either directly from the manufacturer or extrapolated through their claims.


if you have any more rates you'd like me to add that can be verified let me know and i'll add it to the list.

Rear springs

Stock - 174 lbs/in
Bilstein B12 - 186 lbs/in
Wheelers T12 - 195 lbs/in
Icon 52700 - 200 lbs/in

 

[TotalAutomotiveLV]

You might find a shorter coil to be the best fit.

ICON is a 2" Rear Coil (Medium Load). On 5th Gen, without
3rd row seat, some say they net a 2.25" lift at stock weight.

Maybe a 1 or 1.5" coil will be better.

Hope this helps.

_

 

[usdmej]

Maybe a 1 or 1.5" coil will be better.

Hope this helps.

_

i did get a little more than the 2" lift advertised but not significantly more.
the height doesn't bother me, it's the stiff ride which is why im more focused on figuring out if the spring rate is the issue

 

[dezertbomber]

after installing a lift kit for my 4runner (king shocks with stock front spring rate and icon 52700 rear springs) i've found the ride to be too stiff for day to day driving. my vehicle is stock weight with ~150 pounds of added gear (full length roof rack and sliders). when it's just me in the vehicle the ride is noticeably/annoyingly stiff. it only starts to get livable with at least 4 passengers total so i'm guessing ~400-500 pounds added weight. this is pretty consistent with Icon's recommended load range for the vehicle.

i'm currently considering either switching to a softer rear spring or adding some more full time weight to the vehicle. in the meantime, i've compiled a list of available rear springs and their spring rates that i've gotten either directly from the manufacturer or extrapolated through their claims.


if you have any more rates you'd like me to add that can be verified let me know and i'll add it to the list.

Rear springs

Stock - 174 lbs/in
Bilstein B12 - 186 lbs/in
Wheelers T12 - 195 lbs/in
Icon 52700 - 200 lbs/in

You get the adjusters with your Kings in the rear? If so, try adjusting and seeing if that helps.

 

[Offroading is lame]

Icon big bad.


Sent from my iPhone using Tapatalk

 

[usdmej]

You get the adjusters with your Kings in the rear? If so, try adjusting and seeing if that helps.

i did and they are currently set to 1 click from full soft.

the damping isn't the issue, the springs with just 1 person in the car simply don't want to move over bumps. it takes a decent amount of weight in the rear before you can start absorbing large bumps

 

[mrblah]

i did and they are currently set to 1 click from full soft.

the damping isn't the issue, the springs with just 1 person in the car simply don't want to move over bumps. it takes a decent amount of weight in the rear before you can start absorbing large bumps

So the setting for kings for full soft is just regular kings without adjusters...lol. So you might want to set it to full soft, but don't expect a huge improvement or anything for that matter.

Either way, you have only 2 choices:

1. add more weight
2. choose a spring with a softer spring rate.

Suspension is all about compromises. You have to ask yourself what is more important, a nice daily soft suspension when its just you, or a bouncy, saggy suspension when your vehicle is weighed down. Prepare to spend money, if you looking for that "perfect" setup, and keep in mind, everyone's tolerance/comfort levels are different.

They do make "variable" rear springs now, but i haven't really researched them, but when i was shopping for rear springs, I remember them being marketed towards the heavier rigs.....

My experience is the exact opposite of yours. I went from a undersprung vehicle (all the time and 1 blown shock later) to a oversprung, stiff riding vehicle for daily commuting, but its nice and cushy when offroading or when vehicle loaded down.

 

[usdmej]

So the setting for kings for full soft is just regular kings without adjusters...lol.

yes i'm aware, the plan was always to do more high speed stuff later on where i could actually turn up the damping but one issue at a time i guess

i'm actually surprised that a small increase in spring rate (~10%) would make the ride so much harsh. maybe it's because the springs are located so far inboard so is more sensitive to any change in rate.

i'm currently leaning towards trying out the B12s to see how they ride, minus the labor it's a small cost to experiment with

 

[ahtoxa11]

yes i'm aware, the plan was always to do more high speed stuff later on where i could actually turn up the damping but one issue at a time i guess

i'm actually surprised that a small increase in spring rate (~10%) would make the ride so much harsh. maybe it's because the springs are located so far inboard so is more sensitive to any change in rate.

i'm currently leaning towards trying out the B12s to see how they ride, minus the labor it's a small cost to experiment with

I am not convinced that this is a spring issue. I've read about complaints that were very similar to yours: using a 2" spring that's 10% stiffer made the ride too harsh.

I still think it's damping. I'm running Toytech's superflex 2" spring, which is also about 10-13% stiffer and I don't have the issue. In fact, my rear 'softeness' feels about the same as the front according to my butt sensors. My setup is very similar to yours -- 550 lb front springs (OEM rating) with the exception of Toytech 2" spring in the back vs Icon. I am running adjustable Kings in the rear, usually about 4-6 clicks form the softest. If I turn them to the absolute softest, the ride is too mushy and soft.

The main difference is my rears were tuned by Accutune prior to shipping with their own flutter stack or whatever the term is.

Edit: my extra weight is as follows: RSG sliders, skids are aluminum save for the engine skid which is steel. NO other weight -- I have no bumpers, no racks, no spare parts with me when I'm driving to the store. I store zero gear in the back unless I'm heading out to wheel.

 

[mrblah]

I am not convinced that this is a spring issue. I've read about complaints that were very similar to yours: using a 2" spring that's 10% stiffer made the ride too harsh.

I still think it's damping. I'm running Toytech's superflex 2" spring, which is also about 10-13% stiffer and I don't have the issue. In fact, my rear 'softeness' feels about the same as the front according to my butt sensors. My setup is very similar to yours -- 550 lb front springs (OEM rating) with the exception of Toytech 2" spring in the back vs Icon. I am running adjustable Kings in the rear, usually about 4-6 clicks form the softest. If I turn them to the absolute softest, the ride is too mushy and soft.

The main difference is my rears were tuned by Accutune prior to shipping with their own flutter stack or whatever the term is.

Edit: my extra weight is as follows: RSG sliders, skids are aluminum save for the engine skid which is steel. NO other weight -- I have no bumpers, no racks, no spare parts with me when I'm driving to the store. I store zero gear in the back unless I'm heading out to wheel.

IMHO, any aftermarket suspension will be firmer than stock. A 4runner is a pickup truck with a camper on it. There is no way around it. I think social media sets us up for unrealistic expectations. We aint driving a highlander.

Once i realize that lifting our vehicles will decrease onroad comfort no matter what, i stopped caring about onroad comfort, and went nuts on improving offroading comfort, and did the following:

I had toytec superflex and went with dobinson's..which is even MOOOOO STIFF...

For me, I rather sacrifice on road/daily ride comfort for offroad and higher weight capacity because there is nothing worse than getting thrown about your vehicle when you are off the pavement. So i can live with my vehicle riding like a UHAUL truck on road to have a pleasant experience off road. Also, keep in mind, when you have your family and 2 dogs in the vehicle, they will comment on how lovely the ride is...just tell them you sacrifice driving a uhaul every day for them to have that lovely ride..rofl.

However, if you rarely go offroading..then yeah....pick the softest spring rate you want, but you still might not be happy. We are literally driving a pickup with a camper on it. (body on frame).

 

[usdmej]

The main difference is my rears were tuned by Accutune prior to shipping with their own flutter stack or whatever the term is.

.

from my research, accutune's king shock revalve makes them stiffer as they claim the stock valving is too soft, so that would make my situation worse

 

[kevwolford]

after installing a lift kit for my 4runner (king shocks with stock front spring rate and icon 52700 rear springs) i've found the ride to be too stiff for day to day driving. my vehicle is stock weight with ~150 pounds of added gear (full length roof rack and sliders). when it's just me in the vehicle the ride is noticeably/annoyingly stiff. it only starts to get livable with at least 4 passengers total so i'm guessing ~400-500 pounds added weight. this is pretty consistent with Icon's recommended load range for the vehicle.

i'm currently considering either switching to a softer rear spring or adding some more full time weight to the vehicle. in the meantime, i've compiled a list of available rear springs and their spring rates that i've gotten either directly from the manufacturer or extrapolated through their claims.


if you have any more rates you'd like me to add that can be verified let me know and i'll add it to the list.

Rear springs

Stock - 174 lbs/in
Bilstein B12 - 186 lbs/in
Wheelers T12 - 195 lbs/in
Icon 52700 - 200 lbs/in

Just curious, where did you get stock and Icon numbers from?

 

[usdmej]

Just curious, where did you get stock and Icon numbers from?

icon spring rate was directly from them

stock spring rate is extrapolated from wheelers T12 claim that their spring is 12% stiffer than stock

 

[FourT6and2]

icon spring rate was directly from them

stock spring rate is extrapolated from wheelers T12 claim that their spring is 12% stiffer than stock

Old thread, but relevant. I just got off the phone with Icon and they said they do not know, nor publish the spring rate for these springs (2" lift). That said, Eibach's TRD Pro Fox replacement springs that lift the rear 1" are rated at 206 lbs. and people mostly love them and say it's not all that much stiffer than stock. So if you're saying Icon's 200-lb. spring is super stiff, I gotta wonder how stiff it actually is. It's a bit subjective. And this is an old thread, so I doubt you'll see it. But just sharing this info for anybody else in the same situation.

 

[usdmej]

Old thread, but relevant. I just got off the phone with Icon and they said they do not know, nor publish the spring rate for these springs (2" lift). That said, Eibach's TRD Pro Fox replacement springs that lift the rear 1" are rated at 206 lbs. and people mostly love them and say it's not all that much stiffer than stock. So if you're saying Icon's 200-lb. spring is super stiff, I gotta wonder how stiff it actually is. It's a bit subjective. And this is an old thread, so I doubt you'll see it. But just sharing this info for anybody else in the same situation.

i emailed them directly and got a response with the info i posted so i suspect you got a lazy response from a lazy worker. not knowing the spring rate of a spring you sell is pretty wild.

while i didn't say it was super stiff, i do maintain that it's noticeably/annoyingly stiff when driving solo. the vehicle has had significant weight added to it (RTT) and that has definitely smoothed the ride out

 

[FourT6and2]

i emailed them directly and got a response with the info i posted so i suspect you got a lazy response from a lazy worker. not knowing the spring rate of a spring you sell is pretty wild.

while i didn't say it was super stiff, i do maintain that it's noticeably/annoyingly stiff when driving solo. the vehicle has had significant weight added to it (RTT) and that has definitely smoothed the ride out

I think part of my point, which I failed to explain, is that I'm now running Eibach rear springs (1" lift), rated for 206 lbs. And they are only 10% stiffer than OEM according to Eibach. And I really don't feel much of a difference to be honest. And according to you, Icon's 2" rear spring @ 200 lbs. is much too stiff. So if the Eibach springs and the Icon springs are the same spring rate, I gotta wonder...

Eibach: 206 lbs.
Icon: 200 lbs. (according to what you were told)

And yet you're saying Icons are too stiff? I get it's subjective, but at 206 lbs, these Eibach springs don't feel all that different from OEM.