KDSS Friend or Foe?

[Ace Brown]

I own a 15 4Runner Trail with all the bells and whistle that came on the Trail Edition including Kinetic Dynamic Suspension System (KDSS). I installed OME suspension and 33s when new. Now running Toytech suspension. Ive always thought the offroad ride was too rough. Even aired down to 15 its still bad, a real neck snapper. Recently talking with a man who had a 2020 with KDSS and now a 2022 without and he claims the latter is so much better. I also have been told the TRD Pro does not have KDSS. Which suggests the Toyota engineers knew it was not great offroad. But of course the tradeoff is it does improve highway cornering.

Im thinking of having KDSS removed and replaced with regular sway bars. The rig has 145,000 miles on it so no concern with warrantee. I wont get a different 4R without KDSS as i have way too much time and $ invested in modifications now.

Thoughts on this? Anyone gone this route?

Thanks,
Ace


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[TLar25]

I've always just removed the sway bars, and then just adjust your cornering style slightly. I realize this isn't for everybody though. Is your suspension set up for more added weight than you have on your 4runner?

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[jchasse]

It's been on Land Cruisers for 20 years, and people don't seem to think they're too rough.

 

[Ace Brown]

It's been on Land Cruisers for 20 years, and people don't seem to think they're too rough.

That is part of the problem. KDSS was designed for the weight of the LC, not the lighter weight of the 4R.


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[Ace Brown]

I've always just removed the sway bars, and then just adjust your cornering style slightly. I realize this isn't for everybody though. Is your suspension set up for more added weight than you have on your 4runner?

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No it has medium springs both ends and i keep it fairly well loaded.


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[beef tits]

KDSS is awesome. Learn how to use it. Wish my GX had it.

 

[Ace Brown]

KDSS is awesome. Learn how to use it. Wish my GC had it.

There is no “learning”. It’s always on. Some slight modification when in low range and using terrain control.


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[tacollie]

This company makes a switch to disengage KDSS.

KDSS Control Harness Kit (Harness Only)

IF YOU HAVE A PRADO150 not from Asia market. Contact me and send me picture of kdss connector under the dash see install video for location ! If you can order it, that means it’s in stock Out of stock options currently have no time line for re stock. There has been a shortage of parts...

drkdss.com

If you remove it you will get more body roll. It'll also ride better. KDSS isn't great for rough roads at medium speed imo. But neither are sway bars🤣🤣

 

[Ace Brown]

This company makes a switch to disengage KDSS.

KDSS Control Harness Kit (Harness Only)

IF YOU HAVE A PRADO150 not from Asia market. Contact me and send me picture of kdss connector under the dash see install video for location ! If you can order it, that means it’s in stock Out of stock options currently have no time line for re stock. There has been a shortage of parts...

drkdss.com

If you remove it you will get more body roll. It'll also ride better. KDSS isn't great for rough roads at medium speed imo. But neither are sway bars

That looks interesting. Thanks.


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[Cypher]

Hey Ace! Good to virtually see you again.
I have now had an FJC, TRD Pro 4runner with all sway bars intact, another TRD Pro 4runner with the front sway bar removed, and a 200 Series Land Cruiser with KDSS, all with aftermarket suspensions. After all of this I am personally a fan of KDSS simply due to the fact that the on-road handling is so much better (and safer?) all while not sacrificing much if any at all off road. For me the biggest difference in a smooth comfortable ride and a spine shearing rough ride off-road has been the use of shocks with adjustable compression. Now having had Radflo and Icon kits, both with adjustable compression, I don't think I can ever do anything else. Adjusting the shocks to the lowest level of compression resistance and airing down has always made for an incredibly comfortable ride off-road, even with KDSS, in both 4Hi and 4Lo, since in the Toyota's the KDSS setting are different in both. Long story short, before you rip out KDSS, give an adjustable compression suspension kit a try.

 

[Ace Brown]

Hey Ace! Good to virtually see you again.
I have now had an FJC, TRD Pro 4runner with all sway bars intact, another TRD Pro 4runner with the front sway bar removed, and a 200 Series Land Cruiser with KDSS, all with aftermarket suspensions. After all of this I am personally a fan of KDSS simply due to the fact that the on-road handling is so much better (and safer?) all while not sacrificing much if any at all off road. For me the biggest difference in a smooth comfortable ride and a spine shearing rough ride off-road has been the use of shocks with adjustable compression. Now having had Radflo and Icon kits, both with adjustable compression, I don't think I can ever do anything else. Adjusting the shocks to the lowest level of compression resistance and airing down has always made for an incredibly comfortable ride off-road, even with KDSS, in both 4Hi and 4Lo, since in the Toyota's the KDSS setting are different in both. Long story short, before you rip out KDSS, give an adjustable compression suspension kit a try.

Even when i had fancy Icon they were not adjustable. Last time i had adjustable was Ranchos on my Sportsmobile 4x4 Van. Adjustment didn’t seem to change anything. But I will look into that. Thanks.


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[JayOtheMountains]

This company makes a switch to disengage KDSS.

KDSS Control Harness Kit (Harness Only)

IF YOU HAVE A PRADO150 not from Asia market. Contact me and send me picture of kdss connector under the dash see install video for location ! If you can order it, that means it’s in stock Out of stock options currently have no time line for re stock. There has been a shortage of parts...

drkdss.com

If you remove it you will get more body roll. It'll also ride better. KDSS isn't great for rough roads at medium speed imo. But neither are sway bars🤣🤣

I've had a Dr. KDSS installed for the better part of 2.5 years. I have an Icon Stage 4 installed. The product is worth it if you're in terrain that you need KDSS disengaged to travel through but want to keep KDSS for on-road performance. My local streets are garbage in areas and this comes in handy in daily-driving circumstances as well as in over landing (cross-country travel) situations. KDSS stiffens up things beyond 12 MPH to reduce that body roll (in addition to other things), and this switch enables the system to be turned off, thus allowing your suspension to do what it was designed to do. I have been able to travel comfortably down gravel and dirt roads in California, Nevada, Utah, Arizona, Colorado, and Baja at cruising speed with no issues. Dr. KDSS isn't a solution for crawling, since at speeds under 12 mph the system is normally disengaged. What KDSS brings in its ability to keep wheel contact and body roll stability is what makes having it worthwhile. Having the ability to disengage it (read: keep the KDSS solinoid open) when I feel the need to do so (Dr. KDSS) is beneficial. For the price, I'd try this before removing the system and selling it. I feel that it is a benefit to retain, though I sought out my model because it had KDSS, and it was once I discovered that I could disable it my idea of what it is and how to use it changed.

Now, the second part to your problem sounds like you have a stiffer suspension setup which means you need some weight in your rig to help with the spring pre-load. My rig empty is stiff and drives a bit like a sports car. Though if I put some weight on it - tent, fridge, stuff - the pre-load effects are lessened and things get buttery smooth. My suspension was designed with a loaded rig in mind, so I know/understand that daily driving will feel much more stiffer than loaded and travel driving. I do enjoy being able to select that switch to allow my suspension to work as designed, though, on both city streets as well as dirt tracks.

 

[Ace Brown]

So i went to the Dr KDSS site and did some research. It gets complicated. Seems lift over 2” can put things in a bind. My OME was 3.5” as measured. But replaced with Toytech a few years later. The TT ride height was never measured but looks very close. I do believe the TT ride is stiffer than the OME was but that could just be my old memory. BTW I’m referring to slow speed ride quality. Highway manners are great.

I do keep my rig fairly well loaded so it is mostly ready to go whenever. But I believe I’m not a squirrel with it packed with unnecessary stuff. I do have a lightly loaded Baja Rack on the roof. When i went with TT we retained the OME medium rear springs with air bags for trailer support. I use 5 psi with no tongue weight, 15-25 when towing. I don’t pull the trailer off-road so that is not a factor. The front Toytech I believe is medium also, but not positive. My seat of the pants feel says the problem is caused by rear suspension.

Long time off-roader here since 1960. Even desert raced professionally for few years.

Thanks for the suggestions so far.

Ace


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[tacollie]

So i went to the Dr KDSS site and did some research. It gets complicated. Seems lift over 2” can put things in a bind. My OME was 3.5” as measured. But replaced with Toytech a few years later. The TT ride height was never measured but looks very close. I do believe the TT ride is stiffer than the OME was but that could just be my old memory. BTW I’m referring to slow speed ride quality. Highway manners are great.

I do keep my rig fairly well loaded so it is mostly ready to go whenever. But I believe I’m not a squirrel with it packed with unnecessary stuff. I do have a lightly loaded Baja Rack on the roof. When i went with TT we retained the OME medium rear springs with air bags for trailer support. I use 5 psi with no tongue weight, 15-25 when towing. I don’t pull the trailer off-road so that is not a factor. The front Toytech I believe is medium also, but not positive. My seat of the pants feel says the problem is caused by rear suspension.

Long time off-roader here since 1960. Even desert raced professionally for few years.

Thanks for the suggestions so far.

Ace


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3.5" it's a lot. You won't have much down travel. Can you adjust the Toytec to reduce height? I've run Toytec on a couple trucks because the ride was so good.

 

[ETAV8R]

Good information here. I've been shopping for a non-KDSS T4R for months now. Hoping to get one of the last 5th gens.