5th Gen. KDSS vs. Non-KDSS handling performance & sway bar diameter differences.

[jasxn]

Alignment specs are the same...

thank you! I know nothing about alignment and plan on reading up on it soon. but correct me if i'm wrong. wouldnt having aftermarket uca's help with caster? the alignment shop got everything in the green except for caster. But in the combined section everything is green. is that alright?

 

[EddieV4runnin]

does the trail/kdss have a different spec range? i only ask because I just got an alignment done today and i see on the printout stating 4x4 sr5, sr5 premium.

I'll check and update [MENTION=106176]wfo9[/MENTION] might be right. Yet, wrong since there's quite a few threads concerning lean on non-KDSS vehicles. I like to believe it will affect Camber.

Damn it, I brought it up again :lookout:

 

[EddieV4runnin]

Alignment specs are the same...

Not the same will post pictures soon

 

[TfourR]

This is always a very passionate subject for some LOL. I plan on keeping my 2018 for a very Long time. I'm totally confident in my decision to order my truck without KDSS as I plan on modifing and can see no scenario where I would regret not getting it. That's the beauty of the special order process getting what we want. not trying to convince anybody of anything But it's important for the truth and the real facts to be out there about KDSS. It is not a All-Star Offroad player. It has its advantages and it has its disadvantages it all depends on what you're going to use it for and for how long. I'm in a position where I have some inside information on this systems ups and downs which can't share everything and I'm trying to be honest I've been around here a long time and want new people to understand what they're getting into with KDSS that it's not perfect.

Please show proof and or evidence supporting your "truth" and "real facts" regarding KDSS. I think most of us would be very interested in knowing.

 

[AZ Craig]

I was a big fan of my KDSS system until it peed on my floor, killed the dog and spontaneously combusted.

I wish I had never gotten it!

 

[nb rob]

Please show proof and or evidence supporting your "truth" and "real facts" regarding KDSS. I think most of us would be very interested in knowing.

He doesn't have either. His comments on the subject clearly show that he doesn't even know the parameters for the operation.

This is getting old [MENTION=3985]05Runner[/MENTION]. You're making confusing claims that prospective buyers are going to read when they research their vehicles.

Put up or shut up

I'll help you get started. Please elaborate on the foamy hydraulic oil you claimed was the reason that kdss is not available on the TRD pro. Even though the system is locked at 20 kmph.

You want to keep making claims of your inside knowledge, I'm happy to call you out each and every time.

 

[wfo9]

Not the same will post pictures soon

Sorry, they are absolutely the same in practice. I don't make stuff up.

The factory manual will have a slightly different number listed, but they totally overlap and provide for a large spec range.

Basically you want 0 camber, and 3.25 caster for a stock truck. But they are going to give you +/- .75* on both as a valid range. KDSS may specify 3.35 for example for the caster, but if you think for a second that that would make any difference...... don't make me laugh. In practice they have the same alignment specs.. It just confuses people to say anything different.

 

[Jeremy556]

This is always a very passionate subject for some LOL. I plan on keeping my 2018 for a very Long time. I'm totally confident in my decision to order my truck without KDSS as I plan on modifing and can see no scenario where I would regret not getting it. That's the beauty of the special order process getting what we want. not trying to convince anybody of anything But it's important for the truth and the real facts to be out there about KDSS. It is not a All-Star Offroad player. It has its advantages and it has its disadvantages it all depends on what you're going to use it for and for how long. I'm in a position where I have some inside information on this systems ups and downs which can't share everything and I'm trying to be honest I've been around here a long time and want new people to understand what they're getting into with KDSS that it's not perfect.

There's no such thing as a special order 4runner.

What exactly is an "All-Star Offroad player?"

I don't know about you, but I always announce on a public forum of my inability to speak about subjects I'm under an NDA not to discuss publicly. Were you also a Navy SEAL?

 

[jasxn]

I'll check and update [MENTION=106176]wfo9[/MENTION] might be right. Yet, wrong since there's quite a few threads concerning lean on non-KDSS vehicles. I like to believe it will affect Camber.

Damn it, I brought it up again :lookout:

After reading so many threads about kdss lean it seems the earlier 5th gens were more prone to it vs the current. I installed my own lift and at first supported the kdss while disassembling but I had to mess around with it once i was lining up the swaybar to the lca. At one point the kdss was fully extended. But once I put everything together luckily no lean. Maybe I was lucky? Not sure but after messaging a few forum members with kdss with more current 4Runners they didn't have the lean either. Maybe Toyota "updated" the system with the current.

 

[sactown]

I've been around here a long time and want new people to understand what they're getting into with KDSS that it's not perfect.

Nothing is perfect. I would rather have not had KDSS but TRDORs don't come without it around here. Oh well, I'll enjoy the new T4R all the same.

 

[sactown]

What I want to know is what is involved to go from KDSS to non KDSS if so desired?

 

[tpetsch]

What I want to know is what is involved to go from KDSS to non KDSS if so desired?

Oh, That's easy.

Sell the truck with KDSS.

Buy a truck without KDSS.

See, Simple!

 

[DeepSea]

KDSS was specifically designed for both OFF-ROAD and on-road use giving the rear suspension almost 4 inches more travel than non-KDSS equipped ones. It is well worth it as I've had both versions. My experience with non-KDSS is it has way more body roll making the 4R feel top heavy and not nearly as stable as a KDSS equipped one. Many Toyota/Lexus service departments aren't too familiar with them because they rarely see any issues with the system.

Check this in-depth review on KDSS from 4x4 Australia:
https://www.whichcar.com.au/reviews/road-tests/toyota-prado-kdss-test

Here is a quote from it "The other solution is to have some means to vary the tension on the sway bars – softer for off-road; firmer for on-road – which is exactly what KDSS does."

 

[johnbt]

"It is not a All-Star Offroad player."

Can I get a copy of the list of All-Star Offroad players?

Meanwhile, when my KDSS-equipped vehicle majorly malfunctions I'll either have it fixed or scrap it and replace it. As I see it, most of the people worried about KDSS are the ones who can't afford to simply go buy another vehicle. In the meantime, mine is great on the beach and a well-behaved pleasure on the road.

I'm glad I didn't buy a new Land Cruiser. Well, I didn't like either color on the two they had and they were sort of bloated compared to the old ones I remember from decades ago.

John

edited to add:
A buddy in college bought a new '70 Land Cruiser. I think Toyota has lost their way.

 

[DominionRoofs]

All I want to know is that if I buy one without kdss, is it going to be easier to lift and will I have more flexibility with options on lifts?

Sent from my HTC U11 using Tapatalk

 

[Jetboy]

Curious where are you coming up with that number... Seems impossible to me since there are a lot more sr5, and Limiteds on the road. Or did you mean more trail edition 4Runners with KDSS than not. I'm guessing it is a low percentage. Would be interesting to know though...

I'll agree in stock form it is better at low speed offroad. But only in stock form. At speed, the stock non-kdss is better IMHO.

It's a nice feature. The point of this thread was to compare the swaybars.. It's apples and oranges....so really pointless to compare the specs.

I was counting all 150 series. Just in the USA Toyota sells about 30,000 out of the 125,000 150 platform vehicles with KDSS. Out of the 150's in the USA roughly 1/4 have XREAS, 1/4 have KDSS and 1/2 are base suspension models. With the 4runner as a north america vehicle, there's only about 65k sold each year with the base suspension. Compared to somewhere around 150k of the 450k 150 platforms that have KDSS.

The point is that KDSS is not rare.

 

[flea1983]

I was counting all 150 series. Just in the USA Toyota sells about 30,000 out of the 125,000 150 platform vehicles with KDSS. Out of the 150's in the USA roughly 1/4 have XREAS, 1/4 have KDSS and 1/2 are base suspension models. With the 4runner as a north america vehicle, there's only about 65k sold each year with the base suspension. Compared to somewhere around 150k of the 450k 150 platforms that have KDSS.

The point is that KDSS is not rare.

Although that number sounds big, I'd still say it's rare to the average shop. I had never even heard of it till around January this year, although I admit I'm not really a hardcore car person. According to washington post, there were about 17.5 million vehicles sold in the U.S. alone in 2016, so I'd argue that only 30,000 having kdss would make it rare.

 

[wfo9]

KDSS was specifically designed for both OFF-ROAD and on-road use giving the suspension 4 inches more travel than non-KDSS equipped ones.

Really don't want to defend or slam KDSS, but I can't stand to see confusing information.

4" more travel.... No way. It will however articulate better than a stock suspension with standard sway bars on at crawl speeds. Swaybars fight to keep wheels on the same axle at an equal vertical distance from the frame. They are a torsion spring, so in the end... they impact the spring rate on each corner of the suspension but only when there is a delta in distance to the frame across the axle. They basically transfer the spring rate on the unweighted wheel to the weighted wheel and vice versa.

So for pure vertical travel they should have no impact on wheel travel... in articulated travel it will transfer force and attempt to equalize wheel travel across the axle. However, they twist and are a torsion spring themselves, so thickness, material, and the actual suspension spring rates all play together.

BTW, KDSS turns off the normal swaybar behavior by allowing the mount between the frame and the sway-bar to float (below 12mph).

(warning speculation on my part ahead...) Since this float means fluid is moving.... the system is only designed handle this behavior at low speeds without creating too much heat and cavitation.

If KDSS was more of a mechanical disconnect... I would really see no downside at all, but it's implementation on the 5th gen is less than perfect (as most things are). It's still very good for most use cases, just not ideal for all types of offroading. This is why you will never see the system on or anything like it on hard core purpose built offroad rigs. What you will see on those is adjustable sway-bars or pure mechanical disconnects.

 

[vladi80]

inside information on KDSS, ALL STAR Off road player. This is too funny. Relax guy, its a simple hydraulic closed system that performs exceptionally well and even if later down the road you somehow leak out all the juice it wont stop you from getting to your destination.

 

[Jetboy]

The 4runner has a difficult compromise to make. Low floor pan, high articulation, and low body sway is very hard to do. The way Toyota solves the problem is with having its rear springs far inboard. That means less travel of the spring translates to more travel of the wheel. It's part of why a 4runner has a more suspension travel than many other SUVs. But it starts to separate the function of antisway and load support. The springs no longer provide enough righting moment to the body in cornering. The solution is an antisway bar. Another spring that's only function is to resist body tilt. The problem is that doing so then starts to cut into the benefit gained from the narrow spring location.

Toyota's solution is KDSS. IMO it's more of a highway benefit than offroad. For me I would not have bought a 5th gen without it unless I added significant suspension upgrades - and they cost a LOT more than kdss and still would struggle to match the highway handling characteristics. I don't like how soft the handling is without it. The front with proper coilovers could get there with coilovers. I added Fox coilovers already - it's just a valving question. There rear I don't think any shock valving or combination would get to similar handling. The answer out back for me would be ORI struts built into where the stock shock location is. They could be tuned to have just the right resistance and dampening to work really well IMO. But... they are also really expensive by the time you get all the fab work done and then get them installed and tested and valved, etc. And then you'd have to re-adjust for offroad use.

Offroad it offers more than just suspension travel like a sway bar disconnect. It also stabilizes the body and centers it between the axles. And acts to distribute weight more evenly among all 4 tires. It's basically the holy grail of rock crawling - although very limited in form and function compared to the ideal design for crawling. I can see the argument for not being ideal for high speed racing - however I've yet to have the opportunity to compare. I'd love to race on a short course with a similar 4runner with the same suspension without KDSS to compare. And to shoot a few videos of covering similar mogul type terrain. I think with the proper shock valving - it would be faster in desert racing also, but it's not allowed in most desert race classes, so it's hard to get any real world data.

In other motor sports I'm aware of where it is allowed - it's used. Formula 1 cars all use a version of it.

KDSS absolutely has it's limitations. The primary problem is that it uses a single acting cylinder on one side under medium pressure. So it's unbalanced. That's a bummer. There are a few other options for doing the same thing. McLaren has a balanced system with double acting cylinders (if you're not familiar with the difference, that means it has an external shaft on both sides so the fluid volume doesn't change as the piston moves.

KDSS also does not have enough travel for long travel suspensions. The LC200 has more suspension travel and a different KDSS design to go with. So if you want more than the common 2-3" lift, KDSS probably isn't for you unless you have a big budget or do your own fab work. It has potential for just about any suspension setup, but it's not going to be plug and play.

And it will eventually wear out. As of yet we see very few failures. Only a couple documented failures on any KDSS vehicle since they came out in 2003ish. 200,000 miles seems to be easily within the typical operating life. No one knows how long they will ultimately last. My guess is the life of almost all vehicles. Why? Because they aren't active over 12mph. So they're only moving at low speeds. And that means the seals have very few cycles compared to a shock. This idea that they're a 150k mile item has no basis anywhere in experience or data from actual vehicles. It's just conjecture.

Is it for you? That's up to you. IMO drive them back to back. For me it was a must have. If I were building a hardcore offroader - I wouldn't buy a 4runner to start with. (I ran the Rubicon this summer with my mild daily driver - if you want much more out of it - there are better base vehicles that are a lot cheaper. An 80 series is an easy choice. You can build an 80 series for less than just the upgrade cost from an SR5 to a TRD OR.) But if I wanted a harder core offroad 4runner - I'd skip KDSS. It doesn't have the range of travel to accommodate long travel suspension.

I personally wanted the best highway driving of the bunch - it's the KDSS version hands down.