Rear Sway Bar Upgrade for 200 series LC

[RDR78]

I'm thinking of upgrading the rear sway bar on my 2009 LC. Has anyone done this, and if so, any product suggestions (that work w/ KDSS) as well as added fitment products to compliment it ( links?). Or is that even a good idea for getting rid of the body roll on my ride? Greatly appreciate your insights.
Thanks

 

[LCMemphis]

I'm following also.

 

[Taco2Cruiser]

It’s not a good idea.

The KDSS anti-sway bars, both front and rear, are much, much thicker than really anything else out there. Stock or aftermarket. They can be like that because of what KDSS is, an automatic inertia driven hydraulic system that can release when needed. As such, the KDSS anti-sway bars barely twist under load. Any real twist of axle articulation comes from the hydraulic cylinders releasing instead of the bar itself twisting. Like on every other anti sway bar design.

KDSS is quite phenomenal, it has zero inputs from anything. Nothing tells it you’re off road, on road, in low range, going 100mph. It’s a purely separate system of the entire 200 and how it knows when to lock and when to unlock, without even knowing vehicle speed is just astonishing.

The body roll you are feeling is the engineering limits of a modern body on frame 6,000 lbs + SUV with a live rear axle.

This is why the Sequoia is a little nicer of a highway riding SUV. It has an independent rear end, which yields much less body roll. Flip side, independent rear suspensions suck off road, with the exception of an H1.

I’m sure the upcoming 300 series will be even better on road while somehow getting better off road, just as every land cruiser has been.

Yet for trying to “upgrade” a KDSS bar, not going to happen. No one makes one, and how much thicker can it go? 50mm? I mean, I consider myself the nay-slayer, and try almost anything, but sometimes physics and the cost-benefit ratio of modifications are not in our favor.

I’m not one for increasing spring rate, just for cornering ability unless it’s a track car. That said, that’s the only option out there. Get rid of the soft factory springs and stiffen up the suspension, while also forced to lift the truck. Which will in turn, make body roll more significant.

I’m not saying you can’t put thicker bars in a KDSS truck. But you’ll need to find someone who can make them, and have a good amount of money.

 

[Willy beamin]

Drop it

 

[LCMemphis]

Sounds like I got my answer...I learned quite a bit. Thanks for steering us straight.haha

 

[RDR78]

It’s not a good idea.

The KDSS anti-sway bars, both front and rear, are much, much thicker than really anything else out there. Stock or aftermarket. They can be like that because of what KDSS is, an automatic inertia driven hydraulic system that can release when needed. As such, the KDSS anti-sway bars barely twist under load. Any real twist of axle articulation comes from the hydraulic cylinders releasing instead of the bar itself twisting. Like on every other anti sway bar design.

KDSS is quite phenomenal, it has zero inputs from anything. Nothing tells it you’re off road, on road, in low range, going 100mph. It’s a purely separate system of the entire 200 and how it knows when to lock and when to unlock, without even knowing vehicle speed is just astonishing.

The body roll you are feeling is the engineering limits of a modern body on frame 6,000 lbs + SUV with a live rear axle.

This is why the Sequoia is a little nicer of a highway riding SUV. It has an independent rear end, which yields much less body roll. Flip side, independent rear suspensions suck off road, with the exception of an H1.

I’m sure the upcoming 300 series will be even better on road while somehow getting better off road, just as every land cruiser has been.

Yet for trying to “upgrade” a KDSS bar, not going to happen. No one makes one, and how much thicker can it go? 50mm? I mean, I consider myself the nay-slayer, and try almost anything, but sometimes physics and the cost-benefit ratio of modifications are not in our favor.

I’m not one for increasing spring rate, just for cornering ability unless it’s a track car. That said, that’s the only option out there. Get rid of the soft factory springs and stiffen up the suspension, while also forced to lift the truck. Which will in turn, make body roll more significant.

I’m not saying you can’t put thicker bars in a KDSS truck. But you’ll need to find someone who can make them, and have a good amount of money.

Appreciate that insight

It’s not a good idea.

The KDSS anti-sway bars, both front and rear, are much, much thicker than really anything else out there. Stock or aftermarket. They can be like that because of what KDSS is, an automatic inertia driven hydraulic system that can release when needed. As such, the KDSS anti-sway bars barely twist under load. Any real twist of axle articulation comes from the hydraulic cylinders releasing instead of the bar itself twisting. Like on every other anti sway bar design.

KDSS is quite phenomenal, it has zero inputs from anything. Nothing tells it you’re off road, on road, in low range, going 100mph. It’s a purely separate system of the entire 200 and how it knows when to lock and when to unlock, without even knowing vehicle speed is just astonishing.

The body roll you are feeling is the engineering limits of a modern body on frame 6,000 lbs + SUV with a live rear axle.

This is why the Sequoia is a little nicer of a highway riding SUV. It has an independent rear end, which yields much less body roll. Flip side, independent rear suspensions suck off road, with the exception of an H1.

I’m sure the upcoming 300 series will be even better on road while somehow getting better off road, just as every land cruiser has been.

Yet for trying to “upgrade” a KDSS bar, not going to happen. No one makes one, and how much thicker can it go? 50mm? I mean, I consider myself the nay-slayer, and try almost anything, but sometimes physics and the cost-benefit ratio of modifications are not in our favor.

I’m not one for increasing spring rate, just for cornering ability unless it’s a track car. That said, that’s the only option out there. Get rid of the soft factory springs and stiffen up the suspension, while also forced to lift the truck. Which will in turn, make body roll more significant.

I’m not saying you can’t put thicker bars in a KDSS truck. But you’ll need to find someone who can make them, and have a good amount of money.

thanks for the insight Taco2Cruiser. That was pretty much my understanding but was just opening it up maybe for newer product i if not the technology.

 

[TeCKis300]

I’m not one for increasing spring rate, just for cornering ability unless it’s a track car. That said, that’s the only option out there. Get rid of the soft factory springs and stiffen up the suspension, while also forced to lift the truck. Which will in turn, make body roll more significant.

Yup. The only practical option available on the market today for the LC to add roll resistance is going to be stiffer springs than the stock springs. Potentially larger wheels or firmer sidewall tires (LT) to decrease roll compliance in the sidewalls.

I don’t have KDSS, but potentially another avenue is to get the aftermarket to make firmer bushings for the KDSS sway bar mounts and tie rods. This may be an easier path than to engineer new KDSS compatible sway bars as I imagine they are pretty unique pieces.
A note on aftermarket springs, most options are stiffer, but also lift the vehicle. So while the firmer spring rate will help reduce sway, it also changes and reduces the suspensions natural ability to resist roll and dive by way of its geometry. Ideally, there would be firmer springs that don’t lift. Yet most people do want to lift also which is understandable.

Not exactly an option for the LC, but the AHC suspension as found in the LX570, provides incredible on-road handling in my experience of pushing the vehicle. It’s not a sharp scalpel, but it has more handling composure than any 6200lb rig has the right to. Nary any sway or brake dive even in the most aggressive of driving, with excellent body control yet ability to absorb impacts. To do this without any cost to off-road ability makes it unmatched.

 

[bloc]

KDSS is quite phenomenal, it has zero inputs from anything. Nothing tells it you’re off road, on road, in low range, going 100mph. It’s a purely separate system of the entire 200 and how it knows when to lock and when to unlock, without even knowing vehicle speed is just astonishing.

Not questioning this paragraph, but do we know what the lone electro hydraulic valve on the kdss system is for? I guess I assumed it was to enable the system in 4Lo but don’t think I actually read that anywhere.

 

[Taco2Cruiser]

Not questioning this paragraph, but do we know what the lone electro hydraulic valve on the kdss system is for? I guess I assumed it was to enable the system in 4Lo but don’t think I actually read that anywhere.

Not being condescending at all. Where is this "lone electro hydraulic valve" located?

KDSS releases when in high range and not road traction controls are turned off. In fact the first time I ever tested KDSS was when I was driving down a road, and went into a massive ditch thing to see it flex. Which was quite impressive.

 

[bloc]

Not being condescending at all. Where is this "lone electro hydraulic valve" located?

KDSS releases when in high range and not road traction controls are turned off. In fact the first time I ever tested KDSS was when I was driving down a road, and went into a massive ditch thing to see it flex. Which was quite impressive.

Right on top of the main kdss module on the frame.

Now that I think about it I assumed it was a valve. Could be a pressure sensor of some kind.. but there is definitely something with two wires sticking out of it on that assembly.

When I get back home I’ll see about checking whether there’s any current to that pigtail.

 

[Taco2Cruiser]

Right on top of the main kdss module on the frame.

Now that I think about it I assumed it was a valve. Could be a pressure sensor of some kind.. but there is definitely something with two wires sticking out of it on that assembly.

When I get back home I’ll see about checking whether there’s any current to that pigtail.

Sounds good.

 

[bloc]

Sounds good.

In the meantime someone with access to TIS could probably see if there is anything useful in there.

It’ll be another week before I get home from this trip and can do it myself

 

[linuxgod]

I don't see anything electronic in the TIS diagrams

 

[Taco2Cruiser]

I think what @bloc is thinking of is the pigtail for step lights on the LX. It attaches to the KDSS distribution valve shield, but has nothing to do with KDSS. I relocated my pig tails to the top of the frame rail.

 

[bloc]

Well I got under there and you are correct. No valve. No lx step harness either on mine.

I’m betting what I was thinking of was actually in your second TIS picture which pretty clearly shows something sticking sideways off the top of the controller and has a harness wrapping down. My controller has the angled flat face on the body but no valve there. I did spend hours digging through TIS trying to learn about these tricks and think my memory of that is what led me to believe in the valve.

Anyway.. without a control system.. it seems pretty simple. Lean the truck like in a curve.. sway bars still work. Cross up the suspension like when you want/need flex, they no longer work against each other.

 

[Taco2Cruiser]

Anyway.. without a control system.. it seems pretty simple. Lean the truck like in a curve.. sway bars still work. Cross up the suspension like when you want/need flex, they no longer work against each other.

Well... still not so much. That wouldn’t explain how you can be side slopped 25° without any flex, but the cylinders release. Or how you can be fully flexed out, then start to tip and the cylinders lock.

Just admit it, it’s “magic.” Toyota, well really rancho Australia, made a unicorn, killed it, and then put a drop of its blood in every KDSS. That’s... engineering!