Suspension Upgrade - ARB/OME MT64 Discussion

[S SUBERI]

Well put and very net.

 

[DJ’s Sled]

Thank you for your reply, DJ!

A few of my thoughts:

E-KDSS should be fine with all these suspension systems, unless you're really lifting the truck high which seems like it would be beyond about 2.5 - 3 inches or so. Maybe E-KDSS is fine no matter how high the lift, I'm not exactly sure. E-KDSS is the computer-commanded yet still mechanical disconnecting and reconnecting of the sway bars so you get the connected sway bar benefit on-road and the disconnected longer-travel benefit off-road.

The King 2.5 suspension system uses new sway bar links so the King 2.5s must lift enough to require extended links, or maybe they are the same length as stock but just beefed-up (and blue). I really don't know but I'm trying to figure it all out with this new truck!

The AVS system is purely for the harder or softer suspension settings available with the OEM shocks. The aftermarket shocks don't have Lexus AVS so the AVS plug from the truck's computer isn't plugged in to the new shocks and therefore no more harder/softer selectability via the knob on the dash.

To be perfectly honest, the only difference I can feel with AVS is that the truck rolls a lot more in Comfort mode if you hit some big bumps or wavy pavement. There's a truncated off-ramp on my local highway due to construction and I almost lost it while in Comfort mode cruising along at about 60 mph and I had to yank the wheel to the right to hit the off-ramp opening. I've taken it dozens of times in Normal mode and it's perfectly fine. Other than that, Comfort mode is not like you are suddenly riding in a 1969 Cadillac Coupe de Ville when you rotate the knob to Comfort. Similarly, Sport+ mode certainly sharpens cornering but it doesn't seem to make any noticeable difference on broken asphalt, highway expansion joints, etc.

I've also tested Comfort vs. Normal vs. Sport+ while running along at 60 mph through long desert straights on dirt that's relatively flat but also has washboards and ups & downs. No major differences noted. The washboards seem to rattle just as hard in Comfort vs. Sport+. If you hit a big dip or a long stretch of really tight washboards, the stock suspension can't handle it no matter what mode you're in and you'll drift off course.

This is exactly the reason I want to upgrade the suspension. The aftermarket's superior shock technology completely eclipses the stock system so AVS is no longer needed. The aftermarket shocks can act like Comfort mode and then act like Sport+ in an instant. The stock suspension is a compromise that does pretty darn good on-road as well as off-road and the masses of people are fine with it and the price-point is right for the bean counters at Lexus. Aftermarket suspension is expensive and not needed for the vast majority of the masses. If Lexus offered an Overtrail with the OME or King suspension already fitted, the increase in cost would probably be >$10,000. There would also be incredible liability as people drove off the lot and immediately rolled their GX550 while thinking they could drive with reckless abandon.

Bill, that is a freaking awesome set of information and a great reply. Thank you for expanding on those two basic systems with real world examples and your in-depth experience.
That’s a much much better explanation of what I was attempting to try to explain to folks and I’m sure that most of them did get it, but your explanation is way better.

And I got the confirmation back from Slee. Those two smaller parts that we were discussing earlier are in fact only for the LC 250. They are not needed for the GX 550 with this particular lift or height, etc..
And to kind of expand on that general theme, the modest lift that we did does not require a track bar or a diff kit either because we didn’t go that high. They gave me a nice in-depth discussion of when and why that would be needed. But it isn’t needed now for what we’ve done with my particular GX.
Again, thank you for letting everyone better understand how and why a new modern aftermarket system like this can easily surpass and improve upon the stock AVS parts and components that Lexus put in. I too thought about the liability thing, ha ha! I doubt they would ever go that route. However, I know you can get other brands and models with all lifted kits and all that kind of stuff. But again, I don’t know how that works legal or liability wise.

I’m still going to proceed with doing some pretty simple testing over the next several days here on local dirt roads throwing the various systems on, hooking up my Carista OBD scanner, etc. just to see.

 

[Bluegill]

Regarding other models that come with the extra off-road goodies, the Ford Raptor is a perfect example. The Raptor is a version of the regular F150 that has a souped-up engine, remote reservoir Fox shocks, bigger tires, and some different body panels, plus the misc. interior stuff like logos and red stripes everywhere. If you add up all the extras that go into a Raptor vs. a regular 4-door cab F150 with the 3.5 liter V6, it really doesn't add up to all that much. I'd wager that the biggest extra expense is in the suspension. Raptor replacement shocks total about $5-6k and regular F150 replacement shocks are about $850. Yet people line up to pay a good $25-30k more for the Raptor vs. a well-equipped mid-range F150 with the 3.5-liter V6. For Ford, getting an extra $25k for the Raptor badge vs. an F150 badge is genius and obviously well worth the added liability of all the youtubers that film themselves jumping their Raptors and breaking the frames in half.

 

[teghogh]

Regarding other models that come with the extra off-road goodies, the Ford Raptor is a perfect example. The Raptor is a version of the regular F150 that has a souped-up engine, remote reservoir Fox shocks, bigger tires, and some different body panels, plus the misc. interior stuff like logos and red stripes everywhere. If you add up all the extras that go into a Raptor vs. a regular 4-door cab F150 with the 3.5 liter V6, it really doesn't add up to all that much. I'd wager that the biggest extra expense is in the suspension. Raptor replacement shocks total about $5-6k and regular F150 replacement shocks are about $850. Yet people line up to pay a good $25-30k more for the Raptor vs. a well-equipped mid-range F150 with the 3.5-liter V6. For Ford, getting an extra $25k for the Raptor badge vs. an F150 badge is genius and obviously well worth the added liability of all the youtubers that film themselves jumping their Raptors and breaking the frames in half.

Bill, thanks for your feedback on all topics, this one included. Im sure the AVS setup is more expensive for lexus to integrate than aftermarket passive shocks. on the raptor topic, i have had both F150 raptor (gen2, Gen3) as well as the bronco raptor, the difference between them and the stock models are much more significant than shocks. aside from body differences, the chassis is beefed up, medium travel suspension that shares almost nothing with the regular models, upgrades axles, brakes, tires, engine etc.

i have a 25 OT, and i have yet to experience the washboard effect, atleast it is not significant enough to attract my attention. but am suffering from rough idle vibration in the cabin.
@OP, nice setup. im glad that it has resolved your issues. how much lift have you gained with this setup? any change in total travel? if your down travel has increased, does your shop recommend having a differential drop kit?

 

[DJ’s Sled]

Bill, thanks for your feedback on all topics, this one included. Im sure the AVS setup is more expensive for lexus to integrate than aftermarket passive shocks. on the raptor topic, i have had both F150 raptor (gen2, Gen3) as well as the bronco raptor, the difference between them and the stock models are much more significant than shocks. aside from body differences, the chassis is beefed up, medium travel suspension that shares almost nothing with the regular models, upgrades axles, brakes, tires, engine etc.

i have a 25 OT, and i have yet to experience the washboard effect, atleast it is not significant enough to attract my attention. but am suffering from rough idle vibration in the cabin.
@OP, nice setup. im glad that it has resolved your issues. how much lift have you gained with this setup? any change in total travel? if your down travel has increased, does your shop recommend having a differential drop kit?

Hey Teghogh,
I just returned home 2 days ago after the upgrade. My truck is a 2024 OT model. But here is what I’m aiming for:

1. Smallish lift, enough to facilitate slightly larger tires; and to gain some extra off-road clearance - I don’t know exactly what we’ve ended up with. I’m guessing at least 1.5”, but likely more based on some measurements I made yesterday in the garage. An example, I do know that there is noticeably more clearance for the 275/70R18 spare now!
Also keep in mind we intentionally left a bit of rake for adding extra load in the rear. However it’s not nearly as noticeable as the original stock rake.
My Slee Offroad crew said no diff drop kit is needed with how it currently sits. No track bar needed.

2. More towing robustness; more lateral stability and more level - haven’t tested that yet.

3. More unladen plushness around town - certainly seems to be; but no extended opportunity to find out yet. However, I’ll be in C.Springs next week - those are some seriously messed up city streets.

4. Keep No. 1 happy - she hasn’t ridden with the new suspension yet.

5. Lose most or all of the jittery vibration shortcoming - based on my 8 hrs ride home 2 days ago, it seems to have vanished. CAVEAT: I’m still testing on my familiar local roads.

6. To not accidentally mislead any fellow forum members - I’m not promising anyone a rose garden! Your goals may be more singular than mine; I’m aiming for a few goals, so I’m willing to have some slight compromise. And that’s why I’m happy to detail out for everyone what I’m experiencing, noticing, etc.
YMMV as always.

 

[BENDOU]

Thanks so much for all your very insightful feedback. I'm towing an MDC 12 foot caravan that loaded up weights close ot 4800 lbs. This trailer has soft independent off-road suspension and it sure has a tendency to kick the GX into sway when the pavement gets wavy, particularly in turns. Towing in Sport+ helps a bit but not enough. I did put heavier Dobinson rear springs on it which helped a bit but clearly more damping is needed. I had a 2016 4Runner with Kings and never had any problem with sway. So I am really interested in hearing how the towing goes for you.

BTW, I live in Colo Springs and fully agree with the condition of our roads around here. I often joke I need to air-down the tires to run errands around here.

 

[DJ’s Sled]

Thanks so much for all your very insightful feedback. I'm towing an MDC 12 foot caravan that loaded up weights close ot 4800 lbs. This trailer has soft independent off-road suspension and it sure has a tendency to kick the GX into sway when the pavement gets wavy, particularly in turns. Towing in Sport+ helps a bit but not enough. I did put heavier Dobinson rear springs on it which helped a bit but clearly more damping is needed. I had a 2016 4Runner with Kings and never had any problem with sway. So I am really interested in hearing how the towing goes for you.

BTW, I live in Colo Springs and fully agree with the condition of our roads around here. I often joke I need to air-down the tires to run errands around here.

Bendou, that is one nice total setup you have! Congrats on getting it all done. Nice pics.

So our 22’ Imagine XLS is about 4400 dry, and maybe 5500 loaded ready for a trip. It’s a double axle, I haven’t had any serious sway issues. I seem to have the hitch set up correctly..such that with sudden gusts, the entire package moves together. Instead of the trailer going out of control on its own. The hitch has both anti-sway and weight distribution adjustments.
I had 2 previous tow vehicles for it. We still have our AMG GLE43 that we used. It has the air ride self leveling suspension, and plenty of power and a 9 spd transmission. The main shortcoming is it weighs 5000 lbs and can get pushed around a bit too much.
Our ‘22 Sequoia had the length, and weight of 6000 lbs to better handle everything. But the rear had some sag so I had air bags put on that. But in spite of the V8, it suffered some at altitude and climbing up hills, partly due to the transmission being inadequate. And it was no fun as a daily driver. It was traded in for the GX.
I’m trying to avoid airbags on the GX, and I hope the new springs and the rake we dialed in will give us very close to a level situation. And I believe it will give us more lateral strength. We also installed longer, more robust bump stops to better mitigate really deep and sudden dips on some roads…which can cause some bucking and bottoming out. Finally, I’m planning on going to a E load tire to increase lateral support.
I too have tried various drive modes to get better suspension support, but it simply wasn’t enough. On our AMG I had the custom mode set just for towing, and it really works, and the car just flat accelerates up the hills while towing. But again it’s too susceptible to strong winds.
So we shall see soon enough and I’ll post some towing notes on the new suspension.

 

[DJ’s Sled]

Bendou, looking at your pics again. It looks like you have a heavier everyday setup with the bumper, Wavian cans, rooftop load etc. So the guys at Slee would almost for sure recommend the heavier spring option in you case. Which is how the MT64 kit is designed: either the medium or heavier spring options on the rear. Mine is set up with the medium for now.

 

[DJ’s Sled]

Nice write-up. I'd like to know if they made any changes to disable the EKDSS and if so, what needed to be done to prevent error codes.

Garauld,
This follow up for you, straight from Slee:

“ Hi again DJ,

Installing new shocks on a GX550 with E-KDSS is the same process as the previous generation. We do not remove any of the sway bar components during installation. The service ports/valves are opened manually on the E-KDSS valve assembly before raising the vehicle (passenger side outer frame) as per the repair manual. They are then closed manually once the vehicle weight is back on the suspension (on the ground, off the lift). No other steps are required for shock/spring replacement in regard to the E-KDSS system. We also perform a headlight adjustment which is done all electronically.

I hope this helps!

Best Regards,
Amory
Marketing & Sales Support
Team Member Since 2011

Slee Off-Road
700 Pine Ridge Rd
Golden CO 80403 “

And if you need more technical info..exact steps, certainly feel free to call Amory. He is aware that I’m posting info about the install, and they are certainly happy to help.

Thanks for the questions!

 

[Garauld]

Thanks DJ - I was curious which engineers typically are. The main road out front provides a bit of washboard sensation - I may pull the 10A STB-IGR fuse (it feeds power to the EKDSS system) to see what difference it makes to the road feel.

 

[DJ’s Sled]

Thanks DJ - I was curious which engineers typically are. The main road out front provides a bit of washboard sensation - I may pull the 10A STB-IGR fuse (it feeds power to the EKDSS system) to see what difference it makes to the road feel.

Okay, hmmm…that will be interesting.

Presumably the system engineering, testing by Lexus is designed to accommodate the failure of that fuse, and the ability to ‘limp’ home, and then simply install a new fuse.

All of that with no extra issue or need to access the maintenance ports/valves in order to reset everything.

However, without a service manual to reference I really don’t know.

 

[DJ’s Sled]

Thanks so much for all your very insightful feedback. I'm towing an MDC 12 foot caravan that loaded up weights close ot 4800 lbs. This trailer has soft independent off-road suspension and it sure has a tendency to kick the GX into sway when the pavement gets wavy, particularly in turns. Towing in Sport+ helps a bit but not enough. I did put heavier Dobinson rear springs on it which helped a bit but clearly more damping is needed. I had a 2016 4Runner with Kings and never had any problem with sway. So I am really interested in hearing how the towing goes for you.

BTW, I live in Colo Springs and fully agree with the condition of our roads around here. I often joke I need to air-down the tires to run errands around here.

BENDOU,

PM me if you want to consider meeting up while I am over there. Coming over on the third, I’ll be leaving morning of the sixth.
I likely could make it work and meet you somewhere near like a local test track ha ha or circuit that you know is bad and you could do a direct A to B comparison.
If you think you might be interested PM me and we can discuss some other options too that might help you.

DJ

 

[DJ’s Sled]

BENDOU,
That was a nice get together yesterday, I learned a lot!
Here is a picture this AM of the tires still mostly cold, a quick 10 minute jaunt here in town.
So the TPMS is reading low. I actually have 36 cold front, and 35 rear set. So it’s off by about 3 - that’s your reference for yesterday.
Catch you next time, have a great week!
DJ

 

[BENDOU]

BENDOU,
That was a nice get together yesterday, I learned a lot!
Here is a picture this AM of the tires still mostly cold, a quick 10 minute jaunt here in town.
So the TPMS is reading low. I actually have 36 cold front, and 35 rear set. So it’s off by about 3 - that’s your reference for yesterday.
Catch you next time, have a great week!
DJ

It was really nice getting together and getting to drive our GX's back-to-back. Very insightful doing that and certainly will influence my way forward dealing with the sway and GX porpoising experienced while towing.

WRT our discussion on tires, here are a couple of links to the guy I was telling you about that seems to really know his tires. Think you will find this helpful. As we talked yesterday, the tires can influence vibration some. And with us towing trailers, tires become even more important.

This first video talks to how different AT tires may be more oriented to pavement and less to off-road while others have the opposite emphasis.


This next video I found to be very informative. As I mentioned, the old KO2 tires spooked me badly in the wet while my experience with the KO3 has been the total opposite.