Time to sell my Montero and buy a LX!

[chriscosta416]

The short answer is no.

If you feel like you need to account for substantial additional weight, you have a couple of options:

- Add coil spacers
- Replace the springs with aftermarket springs made specifically for AHC

In both cases, you are really just adding a little extra tension to handle extra weight.

Many people do neither and are fine. A lot of people have done the first option. I have done the second option.

What is different with springs made specifically for AHC vs a traditional spring? asking because I never knew AHC specific springs existed. If I do need springs which I am leaning towards I do not - I was planning on getting King springs in a progressive rate from the LC200 non KDSS

EDIT: I would assume AHC springs are just a different spring rate compared to the LC200 ones?

 

[1world1love]

@1world1love , have you put your rig on a scale? Or do you have a good idea what weight you're at?

@radman is pretty built out too. I think he had some scale slips?

I've seen 5100lbs on my rear axle alone when towing. AHC trucks along just dandy.

We were almost 8400 lbs on our drive out to TN last winter, including passengers and dog

 

[1world1love]

What is different with springs made specifically for AHC vs a traditional spring? asking because I never knew AHC specific springs existed. If I do need springs which I am leaning towards I do not - I was planning on getting King springs in a progressive rate from the LC200 non KDSS

EDIT: I would assume AHC springs are just a different spring rate compared to the LC200 ones?

Yeah, they are lower spring rate and progressive, but the actual rates are not published anywhere, either for OEM or for the aftermarket. Aside from that, I can't tell that there is anything different than standard springs.

But several people have tried LC oem and aftermarket and in all cases it caused issues with AHC. Even with the 100 series AHC springs, it will occasionally refuse to go into low height mode.

 

[AnyMal]

Appreciate the response from both of you and ill look into that sensor lift idea.

Regarding coils - As far as I read and expected, LC and LX rear coils are the same OD which means they fit the coil buckets. If I were to put in a LC200 progressive rate coil in the rear say 0-500lbs would it play nicely with the AHC system?

Every spring rate increase just eases AHC loading so technically you can put whatever you want back there. Only drawback would be the ride and not being able to lower or adjust AHC damping rates.

There are a plethora of options for the rears but most are overkill unless you’re planning on static loading 1,000 lbs back there.

Not much trial and error has been done but there are members running diff things from me using double OEM tall, to full aftermarket.

Its the fronts that we dont have anything for. The thing is though, the system likes to be balanced. I have yet to see a good solution for the front, however it has some additional step modulation and gear the rear doesnt have.

 

[chriscosta416]

Every spring rate increase just eases AHC loading so technically you can put whatever you want back there. Only drawback would be the ride and not being able to lower or adjust AHC damping rates.

There are a plethora of options for the rears but most are overkill unless you’re planning on static loading 1,000 lbs back there.

Not much trial and error has been done but there are members running diff things from me using double OEM tall, to full aftermarket.

Its the fronts that we dont have anything for. The thing is though, the system likes to be balanced. I have yet to see a good solution for the front, however it has some additional step modulation and gear the rear doesnt have.

I feel ya, well its good to know the seats are around 110lbs, I just plan to throw some ARB drawers or goose gear drawers in the back with my fridge and dog.

The drawers come out to 100-110lbs and I am not going to bother looking for a stiffer coil for a 50lb fridge.

 

[lx200inAR]

I feel ya, well its good to know the seats are around 110lbs, I just plan to throw some ARB drawers or goose gear drawers in the back with my fridge and dog.

The drawers come out to 100-110lbs and I am not going to bother looking for a stiffer coil for a 50lb fridge.

The problem with non AHC springs is they are set at a spring rate to hold the truck up, since that’s what springs do in typical suspensions. In AHC the spring is specifically designed to not hold the truck up, so that the shocks can modulate height. iE gravity makes the truck go down and AHC pressure makes it go up.

Also, for the shock valving to have any affect there has to be a certain amount of pressure on the system (from the weight of the truck) or it won’t be able to do anything.

So the magic is to be able to get the right spring combination so that the weight of your truck is at the right height at the right AHC pressure. Then everything is golden.

 

[Tex68w]

I want to say the third row seats are roughly 100lbs.

 

[1world1love]

Every spring rate increase just eases AHC loading so technically you can put whatever you want back there. Only drawback would be the ride and not being able to lower or adjust AHC damping rates.

There are a plethora of options for the rears but most are overkill unless you’re planning on static loading 1,000 lbs back there.

Not much trial and error has been done but there are members running diff things from me using double OEM tall, to full aftermarket.

Its the fronts that we dont have anything for. The thing is though, the system likes to be balanced. I have yet to see a good solution for the front, however it has some additional step modulation and gear the rear doesnt have.

Yeah, but just to add, aside from going into Low height mode, stiff springs will prevent the auto-leveling and also the dynamic height adjustment (ie at 65mph), and I believe will cause error codes at that point.

And for the front, you can easily add spacers there. It is functionally equivalent to increasing spring rate.

 

[1world1love]

The problem with non AHC springs is they are set at a spring rate to hold the truck up, since that’s what springs do in typical suspensions. In AHC the spring is specifically designed to not hold the truck up, so that the shocks can modulate height. iE gravity makes the truck go down and AHC pressure makes it go up.

Also, for the shock valving to have any affect there has to be a certain amount of pressure on the system (from the weight of the truck) or it won’t be able to do anything.

So the magic is to be able to get the right spring combination so that the weight of your truck is at the right height at the right AHC pressure. Then everything is golden.

Yeah, I think once I add full skids and LRA, I will be at that magic equilibrium.

 

[bloc]

Has anyone looked into fabricating spring seat adapters to run standard king or eibach coils with AHC struts up front? With the right plastic these could even be 3D printed. Also it isn’t too difficult to get a base spring rate at home as a starting point for someone creative. Or send them off to be measured by someone with the correct equipment.

eibach makes a ridiculous array of coil lengths and rates.

 

[chriscosta416]

Yeah, I think once I add full skids and LRA, I will be at that magic equilibrium.

What have you done to your truck suspension wise?

 

[1world1love]

What have you done to your truck suspension wise?

I have adjusted my sensors for 1" of extra lift and replaced the rear springs.

Builds - One World, One LX Build Thread

Looks great! Adding lights to my Dissent bumper is somewhere on my to do list, would like to get it done before camping season. It looks like the lx570 bumper skin protrudes out further then on the Land cruiser's so it obstructs the "slot" in the bumper where I think you can install lights...

forum.ih8mud.com

I have OEM spring spacers for the front that I will install when it is time to do my next AHC service.

 

[chriscosta416]

I have adjusted my sensors for 1" of extra lift and replaced the rear springs.

Builds - One World, One LX Build Thread

Looks great! Adding lights to my Dissent bumper is somewhere on my to do list, would like to get it done before camping season. It looks like the lx570 bumper skin protrudes out further then on the Land cruiser's so it obstructs the "slot" in the bumper where I think you can install lights...

forum.ih8mud.com

I have OEM spring spacers for the front that I will install when it is time to do my next AHC service.

Got it - I would assume the 100 series in the rear weighs less than the 200 series, what made you decide the TTs would work for you?

 

[1world1love]

Got it - I would assume the 100 series in the rear weighs less than the 200 series, what made you decide the TTs would work for you?

I dont know about the weight difference but the uprated TTs are much beefier than OEM for sure.

And I had no idea if they would work, but there was a lot of speculation on here that they would. Only one way to find out

 

[chriscosta416]

I dont know about the weight difference but the uprated TTs are much beefier than OEM for sure.

And I had no idea if they would work, but there was a lot of speculation on here that they would. Only one way to find out

ah gotcha, so you did no install it yet?

 

[TeCKis300]

Based on some comments, I think it also should be said, the static suspension thinking doesn't completely translate to AHC. It's not the same game played on the LC to tune spring rates and dampers to get the right load handling. The AHC system is already capable of managing that, handling up to ~1800lbs without any help. Not just handling, but dialing in the suspension to handle 1800lbs, so it's not feeling wallowy or underdamped at that level. Because the system will have automatically compensated for it with increased spring rate and damping so it feels generally dialed whether empty or loaded.

Go beyond - sure, there's more strategies to do so and that's where augmentation comes in. Augmentation is not tuning the suspension for load - it does that automatically. It's supporting the system to handle and compensate for additional load. So it can continue to go into high mode for example. Or do so with large sensor lifts.

Copying from another thread, and may help here:

Agreed LC springs even with that build out would be too stiff.

As a baseline frame of reference, here's some rear spring rates for comparison. Too bad I'm missing the LX570 stock spring rate which is likely between the LX470 and King KTRS-79.

Spring - Spring rate (lbs/in)

LX470 AHC - 95
LX570 AHC - ???
King Springs AHC KTRS-79 - 130
LX450 - 150
LC100 - 170
LC200 - 170

More LC200 aftermarket springs for kicks (which IMO are far too high, even for some built LCs)
OME 2720/2721 - 270-340
OME 2722 - 275
OME 2723 - 340
OME 2724 - 400


The AHC hydraulic accumulator based support is progressive by nature. So pre-loading the springs (using 30mm spacers) rather than increasing the rate (King KTRS-79) may be just as effective. At least that's my experience going up to 2000lbs payload and the system works just a stable.

If your rear payload changes much, I would recommend airbags. Good off-road performance and articulation generally wants the lightest spring rates possible. And only as much increased spring rate as necessary, to handle payload. Otherwise the vehicle becomes a stiff legged 3/4 ton truck that doesn't like to articulate or absorb irregularities.

 

[radman]

@radman is pretty built out too. I think he had some scale slips?

Believe it or not, AHC was still functional when I got weighed here. There have been times where i've had a few hundred more pounds in the rig and AHC shuts down (no response when you try to raise from N to Hi).

 

[chriscosta416]

This is really eye opening, I cannot understand how folks say AHC is ineffective now. It sounds like a very tremendous system

 

[TeCKis300]

This is really eye opening, I cannot understand how folks say AHC is ineffective now. It sounds like a very tremendous system

I don't get it either.

There's cats here that will tell us what it will or won't do, even if they have less than zero experience or understanding of the system. (If you're peeking It's not reactionary. It's active.)

There's other niceties too. One being able to slam the suspension in low for easy access when camping, or getting under low ceilings when built with 35s is awesome.

 

[1world1love]

ah gotcha, so you did no install it yet?

No, I did install them. But until then there was no way to know for sure