Wheel Articulation with AHC vs. KDSS

[Taco Supremo]

I'm wondering if anyone could provide any insight into the AHC system on the LX 570. I'm looking at purchasing a 2015 model. I am familiar with the KDSS and how it operates on the 570, the 460, and also certain 4Runner models. I'm curious as to if the KDSS system is on the 570. From the info I can find, it appears like the AHC and AVS act as the replacment for KDSS by providing a firmer ride on flat surfaces but allow greater articulation when the system senses that the axles are becoming crossed, similar to how KDSS works.

And, does anyone know about the RTI scores for AHC vs. KDSS? The only info I could find was on a newer LX and they had to put it into H mode to even get it on a 20 degree ramp without hitting the front fascia. The LX faired pretty well (580 pts.) but the LC blew everthing out of the water with a 660 score. Insane.

Any insight would be appreciated. The vehicle will be mostly road driven as my daily driver but it will be taken offroad where articulation would be needed. My brother has a 4runner with KDSS and I'd like to flex on him a bit tbh. haha.

 

[Madtiger]

And here is a good article: Toyota Land Cruiser vs Lexus LX 570 Suspension Flex Test | Measuring suspension articulation on an RTI ramp

 

[Madtiger]

LC has KDSS. No AHC.

LX has AHC. No KDSS.

Two different system.

If you’re just concern about articulation, either system will give you superb wheel travel. Even at just 580 on LX HI mode, it is still better than your bro’s 4runner.

 

[Taco Supremo]

Understood. Thanks. I was just curious about the RTI scores. Thanks for the Insta post!

And, yes, that is the article I was referring to with the two on the RTI ramp. So if the LX doesn't have to go into H mode it appears to have the same scores as the LC.

With that, I believe the LX automatically goes into H mode when you put the transfer case into 4L. Is that correct? Are you able to keep it in N mode when in 4L?

 

[ramangain]

It looks like a body clearance issue, independent of which suspension setup. Armor up front and back, then retest for a true comparison.

 

[TeCKis300]

With that, I believe the LX automatically goes into H mode when you put the transfer case into 4L. Is that correct? Are you able to keep it in N mode when in 4L?

Yes and yes. When in 4L, all height positions continue to be manually selectable.

Sidehills are also frequently a situation where I will lower the height manually.

 

[bloc]

Stock for stock they will be very competitive on a ramp, with the very slight edge seeming to go to the land cruiser in articulation. (From what I’ve seen over the years here.) But, the LX has high mode on demand which allows greater ground clearance when needed. For the record the RTI “edge” is so small it is basically inconsequential.

Depending on what you do in the future, you can gain significant articulation with an upgraded suspension on the cruiser, but this isn’t an option on the LX without ripping out the fancy adjustable suspension.. and the problem with that is you cannot retrofit the KDSS sway bar system from a cruiser. So you’ll have softer bars than a cruiser on road, and less articulation than a cruiser off-road.

Thing is, the stock AHC is honestly capable enough for most of what people are going to do in a 200 series, as is the stock suspension on a cruiser plus maybe the OE strut spacer. And a push-button lift is frankly pretty awesome.

 

[PDoyle]

 

[grinchy]

I think Canada only got the LX570.

 

[Taco Supremo]

I'm totally sold on the AHC. In theory, it appears to excel at everything with the only possible "downside" being that you can't lift it and it will be pricy to replace. My plans were to run it on the AHC system and then just replace the suspension with the identical OEM lexus stuff anyway as needed. It'll be expensive but I don't feel there's anything aftermarket that touches the AHC as a dual purpose setup. I agree. a push button lift off road, and normal ride with AVS controlling body roll on road is the ultimate.

 

[Taco Supremo]

I think Canada only got the LX570.

Correct, we can not get the LC in Canada.

 

[borfoo3]

That 2 point difference on the RTI score could very well be the difference between the low sidewall LX tires on big wheels vs the fat LC tires

 

[TeCKis300]

I'm totally sold on the AHC. In theory, it appears to excel at everything with the only possible "downside" being that you can't lift it and it will be pricy to replace. My plans were to run it on the AHC system and then just replace the suspension with the identical OEM lexus stuff anyway as needed. It'll be expensive but I don't feel there's nothing aftermarket that touches the AHC as a dual purpose setup. I agree. a push button lift off road, and normal ride with AVS controlling body roll on road is the ultimate.

Actually, lift is probably an area where the system excels. With dynamic lifts beyond what would be practical to run all the time while keeping some droop travel and good CV life.

You're already aware of AHC high position being just over 2".

Add a sensor lift, adjustable up to 1.75" and beyond, and that 2" high position becomes 4".

Add that to the systems automatic extra high position when it detects stucks, and that's 5" suspension lift.

 

[Taco Supremo]

Yes, agreed. So cool. And, like you mentioned, still keeping perfect road manners the whole time. A simply amazing system with the only downside being it will be much higher replacement cost over an aftermarket setup, which I am totally fine with if it means the superb functionality that you've detailed.

That's for the info. Very helpful.

Actually, lift is probably an area where the system excels. With dynamic lifts beyond what would be practical to run all the time while keeping some droop travel and good CV life.

You're already aware of AHC high position being just over 2".

Add a sensor lift, adjustable up to 1.75" and beyond, and that 2" high position becomes 4".

Add that to the systems automatic extra high position when it detects stucks, and that's 5" suspension lift.

Have you had any accelerated wear issues with your CV's after doing a sensor lift being that it's fulltime 4WD?

 

[ramangain]

A simply amazing system with the only downside being it will be much higher replacement cost over an aftermarket setup.

Not strictly true. Price out AHC OEM spring and damper cost vs. high quality aftermarket parts. The extra cost for AHC is in the globes and pump/motor, which both last a very long time (at least on 100 series rigs). The wildcard is replacing the AHC lines if rust chews them up. I wouldn't wish that job even on my worst enemy.

 

[bloc]

Actually, lift is probably an area where the system excels. With dynamic lifts beyond what would be practical to run all the time while keeping some droop travel and good CV life.

You're already aware of AHC high position being just over 2".

Add a sensor lift, adjustable up to 1.75" and beyond, and that 2" high position becomes 4".

Add that to the systems automatic extra high position when it detects stucks, and that's 5" suspension lift.

Thing is, even regular high mode reduces potential for down travel, and therefore articulation, as seen in edmunds ramp video. A sensor lift will exacerbate that issue.

 

[Taco Supremo]

Thing is, even regular high mode reduces potential for down travel, and therefore articulation, as seen in edmunds ramp video. A sensor lift will exacerbate that issue.

Yes, that's a great point. Ideally I guess you'd want to drive it in N mode while offroading to maintain the full articulation, and then move to high mode when increased clearance but less articulation would be momentarily beneficial?

 

[GordJ]

Correct, we can not get the LC in Canada.

There’s a few around.

 

[bloc]

Yes, that's a great point. Ideally I guess you'd want to drive it in N mode while offroading to maintain the full articulation, and then move to high mode when increased clearance but less articulation would be momentarily beneficial?

That is how I would drive it. But, I don’t have much experience with an LX on trail. Just an understanding of how the respective systems work.

 

[TeCKis300]

Thing is, even regular high mode reduces potential for down travel, and therefore articulation, as seen in edmunds ramp video. A sensor lift will exacerbate that issue.

I don't disagree. The same trades with a traditional lift would be true. Fortunately with AHC, one does have a choice on the fly with how best to optimize the system. Including the potential use of AHC Low which may RTI even higher.