KDSS on road behavior

[wfo9]

i think you may be missing the point that a few people are making though. those are all criticisms of the heavy sway bar and not KDSS itself. if you paired the KDSS with the same sway bar you wouldn't have those disadvantages but would have the added advantage of more articulation at low speed.

Yes, if KDSS used a traditional swaybar that could be easily removed, replaced. or ratio adjusted... It would be great, but KDSS is an integrated system. You can't do anything with it besides use the swaybar provided.

What you can possibly do is figure out a way to force the system into an open mode at speed. But the long term durability would be questionable with the pistons cycling that fast.

There was one guy on here who did that and said he was having great results at mid speed off-road scenarios...

 

[wfo9]

A similiar thing happens to me if I come off or enter the freeway a bit too hot. The truck leans a little, then the power shuts off to the wheels and it pulls in the opposite direction of the turn. It's a bit disconcerting...

That is most likely not KDSS. It is the stability control system engaging the ABS on one wheel. It thinks you are about to roll over.... It can be a very unnerving feeling.

You can try a zero point calibration.. If that is off... it will happen more often in one direction.

 

[wfo9]

For those discussions where KDSS is stated as not ideal for faster offroading, how is this impacted with a coil-over setup? I mean is that statement across the board stock suspension and one equipped with many of the aftermarket offerings?

The typical rule of thumb is you lighten up the swaybars as you add spring rate and or dampening. The stiffer the sway-bar the more it jacks with your spring rates and the more control/traction you will lose in uneven terrain at speed. You simply can't have you cake and eat it too (although everyone on here seems to think there is some magic way)

But again, this is only at speed in rough off-road terrain. So few people take on that use case that I would bet hardly anyone would be disappointed with the overall performance.

The only reason I got back on this stupid thread was someone quoting me and stating they could not fathom any reason to not have KDSS on the TRD pro....

 

[b407driver]

The only reason I got back on this stupid thread was someone quoting me and stating they could not fathom any reason to not have KDSS on the TRD pro....

Well, sorry for waking the beast. I was just curious why you thought that.

But I stand by my assertion that for the market that buys the TRD Pro (no, they are not all desert pre-runners, despite Toyota's marketing to the contrary), KDSS would have been a no-brainer, except for the increase in cost. KDSS makes it difficult to mess with your suspension, and logic should dictate that anyone buying such an expensive (TRD) suspension 'upgrade' won't... well, upgrade it.

But again, this is only at speed in rough off-road terrain. So few people take on that use case that I would bet hardly anyone would be disappointed with the overall performance.

Exactly my point; for 99% of the TRD Pro buyers, it would have been a win-win.

Absent one of those Toyota engineers who were there for the development of the TRD Pro chiming in, anyone's opinion here is anecdotal at best, absent an A:B C?) test on the same road, in the same conditions. And with the same butt-dyno in the seat for each run.

If you have ridden in, or driven, a TRD Pro with KDSS and think the ride off-road sucked due to the mis-matching of the KDSS with the suspension, I'd love to hear details. But don't feel like you have to reply just because I quoted you (again), just trying to provide context to the conversation.

PS: And please correct me if I'm wrong, but I'm pretty sure that the front and rear OEM shocks installed on KDSS vehicles and non-KDSS vehicles are identical. Apparently Toyota didn't seem to think that introducing KDSS into the equation should require completely different shock/spring characteristics.

 

[Throwback]

Interesting stuff. So, why do guys buy the TRD Pro if they're not looking to do high speed desert prerunning?

For normal trail riding and such, what advantages does the TRD Pro have over a Trail Edition with KDSS? Does the TRD Pro have the locking rear diff, MTS, Crawl Control, etc?

The info on the Toyota website mainly pushes a "desert racing heritage" and focuses on the aesthetics of the truck, not the capabilities outside the Bilstein shocks/springs and an aluminum skid plate.

 

[1engineer]

Interesting stuff. So, why do guys buy the TRD Pro if they're not looking to do high speed desert prerunning?

For normal trail riding and such, what advantages does the TRD Pro have over a Trail Edition with KDSS? Does the TRD Pro have the locking rear diff, MTS, Crawl Control, etc?

The info on the Toyota website mainly pushes a "desert racing heritage" and focuses on the aesthetics of the truck, not the capabilities outside the Bilstein shocks/springs and an aluminum skid plate.

Very few people outside a small enthusiast's circle know anything about different suspensions. Case in point: Read this thread and pick out the half dozen or so that know how KDSS works and it's application.

TRD Pro offers a nice soft suspension. Really no advantage for normal trails. Then again for normal gravel and dirt roads KDSS offers no advantage either because you don't need any additional articulation. On the road is where most will appreciate KDSS.

 

[Jaydub514]

Interesting stuff. So, why do guys buy the TRD Pro if they're not looking to do high speed desert prerunning?

For normal trail riding and such, what advantages does the TRD Pro have over a Trail Edition with KDSS? Does the TRD Pro have the locking rear diff, MTS, Crawl Control, etc?

The info on the Toyota website mainly pushes a "desert racing heritage" and focuses on the aesthetics of the truck, not the capabilities outside the Bilstein shocks/springs and an aluminum skid plate.

This is like asking why people buy a Subaru Impreza WRX STi or Mitsubishi Lancer Evolution (RIP) if they aren't looking to rally race.

I know it's crazy for some people to comprehend, but there is a large percentage of people who buy the TRD Pro because you know - they just want to? The differences have been talked about ad nauseum here and in an effort to not turn this into another Trail or TRD Pro thread we won't go there.

And yes, the TRD Pro has the rear e-locker, crawl control, and multi terrain select.

 

[blues]

I like KDSS and the features that the TEP offers because when I need them, I'll have them.

I don't really do any (elective) off-road except for our rural gravel and often poorly graded steep and winding roads and the occasional Forest Service road to a local trail head...

...but in these parts you never know when the next monsoon or snowstorm is heading your way and the peace of mind of having a great system to address most of what we may encounter is very reassuring.

The stock TEP with KDSS supplies that in spades.

 

[wfo9]

Exactly my point; for 99% of the TRD Pro buyers, it would have been a win-win.

But when you build a truck with a Toyota Racing Development badge on it. And take the press out to the desert to test drive it... You want it to perform well in those particular conditions.

Absent one of those Toyota engineers who were there for the development of the TRD Pro chiming in, anyone's opinion here is anecdotal at best, absent an A:B C?) test on the same road, in the same conditions. And with the same butt-dyno in the seat for each run.

If you have ridden in, or driven, a TRD Pro with KDSS and think the ride off-road sucked due to the mis-matching of the KDSS with the suspension, I'd love to hear details. But don't feel like you have to reply just because I quoted you (again), just trying to provide context to the conversation.

Yes, it is all opinion. That is what I said before...

PS: And please correct me if I'm wrong, but I'm pretty sure that the front and rear OEM shocks installed on KDSS vehicles and non-KDSS vehicles are identical. Apparently Toyota didn't seem to think that introducing KDSS into the equation should require completely different shock/spring characteristics.

I was talking about real off-road suspensions that could handle hard core mid to high speed off-road.... The stock stuff simply can't deal with much and is lightly sprung and dampened. In that case, the stiff sway bar has much less impact. If you ramp up the spring rates and dampening the swaybar will start to fight you more. It has to be adjusted with the rest of the suspension to get the best results. And it's impossible to get it ideal for all conditions. There is one KDSS swaybar for the 5th gen (A very awkward one at that). Yes, Toyota could have probably come up with one tuned better for the TRD pro suspension so it would perform well at speed offroad. But that was obviously cost prohibitive.

I'll never understand the KDSS fanboys. Saying it is good... is never enough for them. I have no skin in this game, just try to educate people on the pros and cons and learn a few things along the way. But some people can't ever admit that something is not 100% the best choice for everyone and all conditions and use cases. I've been racing and building things as a hobby for 35+ years now. I've learned it is never black and white.... It's always shades of gray and you adjust and compromise for your particular use case. If you have not found the flaws or limitations yet... it is just a matter of time... But somehow, certain 5th gen owners have the perfect answer. :loco:

And just to re-state so nobody gets confused. I think KDSS is a good system. It works well for most people. It's just not the best choice for everyone and all scenarios. It's also overkill for many....

 

[e60ral]

Interesting stuff. So, why do guys buy the TRD Pro if they're not looking to do high speed desert prerunning?

For normal trail riding and such, what advantages does the TRD Pro have over a Trail Edition with KDSS? Does the TRD Pro have the locking rear diff, MTS, Crawl Control, etc?

The info on the Toyota website mainly pushes a "desert racing heritage" and focuses on the aesthetics of the truck, not the capabilities outside the Bilstein shocks/springs and an aluminum skid plate.

it looks cooler

 

[b407driver]

But when you build a truck with a Toyota Racing Development badge on it. And take the press out to the desert to test drive it... You want it to perform well in those particular conditions.

And that's the interesting part of the article you linked; they did exactly that, and it appeared to perform fine (or not, depending on how you interpret any lack of concrete evidence to the contrary). You could say that its absence on the TRD Pro is proof, but I'd not necessarily agree (see below).

I'll never understand the KDSS fanboys. Saying it is good... is never enough for them. I have no skin in this game, just try to educate people on the pros and cons and learn a few things along the way. But some people can't ever admit that something is not 100% the best choice for everyone and all conditions and use cases. I've been racing and building things as a hobby for 35+ years now. I've learned it is never black and white.... It's always shades of gray and you adjust and compromise for your particular use case. If you have not found the flaws or limitations yet... it is just a matter of time... But somehow, certain 5th gen owners have the perfect answer. :loco:

I suppose you are probably lumping me in there and so be it; I don't pretend to know much about all this technical stuff (which is why I ask questions here of people like you), but I did choose to buy a vehicle with KDSS because of back-to-back-to-back-to-back test drives of an SR5, TEP w/KDSS, Limited and GX460 (only on the same smooth and bumpy roads, admittedly). I appreciate your technical insight as to why KDSS and/or a stiffer swaybar isn't suited to high-speed offroad driving, and I get that the TRD suspension was supposedly tuned toward the soft side, and to dissipate heat.

All of that TRD marketing bullshit ('high-speed desert heritage', or whatever) is just that, marketing. I think you and I would both agree that Toyota didn't tune those TRD shocks/springs purely for racing, nor did they build the TRD Pro for the express purpose of high-speed desert runs. They built it for the express purpose of creating a low-volume niche product that they could mark up and make money on, and they certainly achieved that goal; 'looks' are indeed most of it, and come 2017, it only gets further diluted.

I certainly never suggested that KDSS is best for everyone, merely that for 95% of the TRD Pro owners out there its inclusion would not have impacted it in a negative way. Considering all the TRD Pro-bashing that goes on around here, I'm actually a bit surprised anyone is interested in debating the point.

The only negative (not related to re-lifting or working on suspension) that was provided above was that it was not tuned to high-speed, desert type rolling, which most everyone admits very, very few people do. Marketing aside, of course. For the intended 'offroad' crowd, KDSS' increased articulation aspect could only be seen as a marketing benefit, one that Toyota chose to ignore.

Anecdotal opinion aside, for all we know the TRD suspension is, in reality, perfectly matched to the KDSS system, and drives even better than a Trail w/KDSS (or a TRD Pro, for that matter). I understand that it theoretically shouldn't, but who actually knows without comparing said vehicles?

The one thing I'll stand by is that Toyota chose not to put KDSS into the TRD Pro not for performance reasons, but for profit reasons, as someone alluded to above. If they thought they could sell more with KDSS and make a bigger profit, I'm sure they would have considered it. But without raising the price of the Limited, I'm not sure how that would have played out. I still wonder to this day why Toyota chose to make two prototypes of the TRD Pro, both with KDSS. It appears they did it not so much to test it, but to impress the media.

Sorry if you think we're all beating dead ponies here, but I think it's been an enlightening discussion (that's certainly run its course), despite how annoying it may have been.

Cheers...

 

[Throwback]

Does anyone know what speed the KDSS switches modes from locked/street to unlocked/articulation?

 

[wfo9]

Does anyone know what speed the KDSS switches modes from locked/street to unlocked/articulation?

Good question. I can't remember the source, but I remember 12mph being the magic number. There was speculation that this was the fastest speed that the open mode could keep up (but this was pure speculation)

There is still some mystery to exactly how it works.

There is some electronic control and a dedicated stabilizer control ECU...

 

[Throwback]

I was running some forest service roads today and was up to 20-25mph in a few sections. It felt to me that the KDSS switched to highway mode and I was thinking, "Oh... now I understand the allure of the TRD Pro."

 

[Throwback]

I haven't done *any* research on upgrading the Trail shocks yet. I've been too busy harassing Discount Tire with swapping out different AT tires under their 30-day ride satisfaction guarantee.

Once that's squared away and I have 5 matching tires I'm happy with I'll take on the next challenge. Regardless, if the KDSS kicks in over 12mph I don't quite see the advantage of upgrading shocks on a Trail. Is better high-speed off road performance possible in a KDSS rig?


*EDIT* Looks like this reply was to a post that is now deleted.

 

[Vinsil]

I won't get into the pissing match but some good info shared here. I've built some hardcore wheelers in the past and had a few of my toys in a magazine.

Having said that...my Runner is for my wife to commute and haul our kids in 99% of the time. I was leary of kdss but if really is nice for the road. We only have 113 miles on the truck so far and mods will happen before it heads off road. I'm confident that it will fill the roll of a fun time hitting fire service roads and mild trails in Oregon like browns camp. I've done the big stuff and while fun, the dedicated trail rigs get old too.

I don't view the Runners as a GREAT platform to build a hardcore rig from but..those that push the limits will rip things like kdss from it and do a sas eventually anyway. :bounce:

Thanks for the lesson, it was insightful.

This is the FIRST truck I've owned that I'm not going to push over the top. Mild lift, tires...typical trail build is all and the trail with kdss fits that roll well.

 

[wfo9]

I haven't done *any* research on upgrading the Trail shocks yet. I've been too busy harassing Discount Tire with swapping out different AT tires under their 30-day ride satisfaction guarantee.

Once that's squared away and I have 5 matching tires I'm happy with I'll take on the next challenge. Regardless, if the KDSS kicks in over 12mph I don't quite see the advantage of upgrading shocks on a Trail. Is better high-speed off road performance possible in a KDSS rig?


*EDIT* Looks like this reply was to a post that is now deleted.

Yes, you can still get better offroad performance with KDSS via better shocks/coils/struts....

If both wheels compress/droop at the same time, The swaybar has every little negative effect. It's when each wheel on the same axle goes in a different vertical direction that it will fight the rest of the suspension. It more or less tries to equalize wheel travel across the axle.

I mostly run my truck without swaybars off-road. When I connect it back up it feels absolutely horrible to me off-road. The difference is night and day at pretty much any speed. The only time you really want stiff swaybars offroad is when you are on a side hill. Some swaybar is good, but it really needs to be adjusted for the conditions and the rest of the suspension to not get in the way off-road. KDSS does a decent job of getting it out of the way in low speed conditions.

But honestly, most offroading in a 5th gen is slow speed anyway. It's just not a good hard core platform. So just slow down and enjoy the mild to slightly aggressive traisl.... That is where KDSS shines. If high speed is your goal.... You really need a long travel setup to get crazy and you cannot run a front sway bar at that point.

I still stand by the assertion that KDSS was not included on the TRD pro for reasons other than profit margin. My opinion is the truck is better aligned with the thrust of the TRD lineup without it and that a factory lifted vehicle had much simpler reliability model with a traditional swaybar system. That is just one mans opinion though..

Also, the TRD pro impressed me out of the box...It does everything pretty darn well for a stock vehicle. It reminds me of the Trail team FJ we have. It's a nice little package right out of the showroom.

 

[TK-422]

I think you are missing the point. You have modded your 4Runner way more than 99% of us would ever do on a new vehicle.

I had a 1990 Bronco that I did a full 1 ton SAS on and beat the crap out of it. If stuff broke I would go to the junk yard or weld it back together.

There is no way I would do that with a 1 year old vehicle.

However I do offroad frequently with the So Cal group and we do run black diamond runs quite often. I have KDSS and after test driving with and without on roads it was a no brainer. I did many runs offroad and it did just fine except for the ground clearance.

I recently added a Toytech lift and KO2s to my KDSS 4Runner and it not only added the ground clearance but also reduced the nose dive. It is still great on the street. When doing a sharp turn or entering a round freeway entrance it stays level with no body roll.

When off road it chugs along just fine. I have gone up rocky slippery hills I thought it had no chance at with no problems. If you follow Miah on washboard roads you know he always goes balls out. As long as your tires are aired down you will still have teeth at the end of the day.

In conclusion If your 4Runner is not a beater and you do not plan on lifting it 2 feet or making it into a full SAS swap you will most likely benefit from having the KDSS suspension if you can afford the $1700 price.

 

[wfo9]

I think you are missing the point. You have modded your 4Runner way more than 99% of us would ever do on a new vehicle.

I had a 1990 Bronco that I did a full 1 ton SAS on and beat the crap out of it. If stuff broke I would go to the junk yard or weld it back together.

There is no way I would do that with a 1 year old vehicle.

However I do offroad frequently with the So Cal group and we do run black diamond runs quite often. I have KDSS and after test driving with and without on roads it was a no brainer. I did many runs offroad and it did just fine except for the ground clearance.

I recently added a Toytech lift and KO2s to my KDSS 4Runner and it not only added the ground clearance but also reduced the nose dive. It is still great on the street. When doing a sharp turn or entering a round freeway entrance it stays level with no body roll.

When off road it chugs along just fine. I have gone up rocky slippery hills I thought it had no chance at with no problems. If you follow Miah on washboard roads you know he always goes balls out. As long as your tires are aired down you will still have teeth at the end of the day.

In conclusion If your 4Runner is not a beater and you do not plan on lifting it 2 feet or making it into a full SAS swap you will most likely benefit from having the KDSS suspension if you can afford the $1700 price.

No I think you are missing the point. Please read more than one post before responding. It's like talking to a cult LOL.

And no... my truck is not a beater as you implied, and yes I could easily afford the 1700 price tag. I just don't want it (and that is OK). I know it bothers you guys... but deal with it.

I brought up removing the sway bars as a point of reference for what a truck feels like with and without sway-bars off-road in various conditions. And if you must know, my truck actually has a front sway bar on it... I have a custom disconnect system that allows me to take it on/off while airing down/up. Some people on here are actually trying to have a productive conversation. I know it has went a bit off topic.. but that is how it works on here.

There are pros and cons to KDSS (mostly pros). I think I've reiterated that in almost all of my responses.. but that is never enough for you guys. I've learned to do that because of countless misunderstandings, but I guess that is still not enough. :frusty:

 

[1engineer]

No I think you are missing the point. Please read more than one post before responding. It's like talking to a cult LOL.

And no... my truck is not a beater as you implied, and yes I could easily afford the 1700 price tag. I just don't want it (and that is OK). I know it bothers you guys... but deal with it.

I brought up removing the sway bars as a point of reference for what a truck feels like with and without sway-bars off-road in various conditions. And if you must know, my truck actually has a front sway bar on it... I have a custom disconnect system that allows me to take it on/off while airing down/up. Some people on here are actually trying to have a productive conversation. I know it has went a bit off topic.. but that is how it works on here.

There are pros and cons to KDSS (mostly pros). I think I've reiterated that in almost all of my responses.. but that is never enough for you guys. I've learned to do that because of countless misunderstandings, but I guess that is still not enough. :frusty:

KDSS is just like any other product. People feel they have to justify their purchase because... human nature.

If they had put KDSS on the PRO people would have complained it was too high a price point. People would complain it was no good in high speed off road. It does not have it and people complain they need it!

It's like tires, or wheels, or CAI, or Icon, or anything else. Typical person: "I paid $$$$ so it is the best and damn it I am going to convince everyone else that it is the best!" Never mind there are 1000 ways to skin that cat and all of them work.