Improving Off road capability in AHC equipped AHC (1 Viewer)

[Cantatan]

I have an AHC equipped Landcruiser that I want to make a little more off road capable but am cognizant that anything I add will add weight which I want to avoid as it will impact the AHC.

I don't intend doing anything extreme so I am looking for the changes that will stop me getting stuck in soft sand, snow, mud etc. only. These can be both modifications to truck as well as accessories to carry. The only reason that I am considering sliders is so that I will have jacking point for a Hi-Lift jack if needed however I could also just get the kit that fits on the wheel. I feel a winch would put too much load on front and really depending where you get stuck may not be much help. All advice appreciated.

 

[cjmoon]

lockers and a winch would be my fist go to. larger tires more aggresive pattern? modification to suspension will not affect you getting stuck

 

[kreiten]

I have an AHC equipped Landcruiser that I want to make a little more off road capable but am cognizant that anything I add will add weight which I want to avoid as it will impact the AHC.

I don't intend doing anything extreme so I am looking for the changes that will stop me getting stuck in soft sand, snow, mud etc. only. These can be both modifications to truck as well as accessories to carry. The only reason that I am considering sliders is so that I will have jacking point for a Hi-Lift jack if needed however I could also just get the kit that fits on the wheel. I feel a winch would put too much load on front and really depending where you get stuck may not be much help. All advice appreciated.

I've run Rubicon twice on AHC and a number of other trails, don't let AHC hold ya back I think it's a great system so long as it's working(knock on wood) I run Wheeler bump stops up front and Medium duty Old Man Emu springs in the rear(to help with the weight of the rear bumper, spare, cans etc) Part of the reason I love running the heavier springs in the rear and the bigger bump stops up front is if the system did take a s**t on the trail I could still drive off without the suspension totally collapsed. I have air lockers front and rear, 4.88 gears, summo transfer case gears, ARB front bumper, Coastal Offroad rear bumper etc.. Load the rig up, make mods as needed to run the kind of trails you wanna run, don't let AHC hold ya back, these rigs will take an absolute pounding. Hope that helps, good luck buddy and get out there and start adventurizing! -Ken

 

[Mike NXP]

I've run Rubicon twice on AHC and a number of other trails, don't let AHC hold ya back I think it's a great system so long as it's working(knock on wood) I run Wheeler bump stops up front and Medium duty Old Man Emu springs in the rear(to help with the weight of the rear bumper, spare, cans etc) Part of the reason I love running the heavier springs in the rear and the bigger bump stops up front is if the system did take a s**t on the trail I could still drive off without the suspension totally collapsed. I have air lockers front and rear, 4.88 gears, summo transfer case gears, ARB front bumper, Coastal Offroad rear bumper etc.. Load the rig up, make mods as needed to run the kind of trails you wanna run, don't let AHC hold ya back, these rigs will take an absolute pounding. Hope that helps, good luck buddy and get out there and start adventurizing! -Ken

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@Cantatan you plan on doing any wheeling like what previous the post is showing?


Your description sounds like you will be starting with some light duty off road fun. If so then you don't need to modify anything you already have a extremely capable vehicle . Hi lift jacks are not necessary for most type of situations but if you wanted to throw one in the trunk with the wheel lift attachment that may be a good option. I had mine for three years, never touched it once. If I get a flat, I'd rather plug the tire and air up then remove my spare.

I could see if you are bogged down deep, lifiting a wheel and putting a traction board under to help get out. I prefer to just not get that stuck in the first plce. Once you feel the rig sinking, STOP, and recover yourself or else it is a beached whale. It's not like lighter vehicles that you can just rip and rally on. The cruiser will sink, once your on frame rails it's hard to get out with self recovery.


Do you have a rear trailer hitch? Could get a hitch mounted winch and keep it in the trunk for emergency and remove it when not needed.


Otherwise, get some capable tires and a set of maxtrax and there isn't much that rig can't do ( short of big rock climbing )



... and that's how it all starts. That was my attitude for the first year or two. Take your time and make sense of what modifications you need not what looks good on other peoples trucks.

Before you know it, you will be in a fully built armored rig lol . Have some fun

 

[kreiten]

@Cantatan you plan on doing any wheeling like what previous the post is showing?


Your description sounds like you will be starting with some light duty off road fun. If so then you don't need to modify anything you already have a extremely capable vehicle . Hi lift jacks are not necessary for most type of situations but if you wanted to throw one in the trunk with the wheel lift attachment that may be a good option. I had mine for three years, never touched it once. If I get a flat, I'd rather plug the tire and air up then remove my spare.

I could see if you are bogged down deep, lifiting a wheel and putting a traction board under to help get out. I prefer to just not get that stuck in the first plce. Once you feel the rig sinking, STOP, and recover yourself or else it is a beached whale. It's not like lighter vehicles that you can just rip and rally on. The cruiser will sink, once your on frame rails it's hard to get out with self recovery.


Do you have a rear trailer hitch? Could get a hitch mounted winch and keep it in the trunk for emergency and remove it when not needed.


Otherwise, get some capable tires and a set of maxtrax and there isn't much that rig can't do ( short of big rock climbing )



... and that's how it all starts. That was my attitude for the first year or two. Take your time and make sense of what modifications you need not what looks good on other peoples trucks.

Before you know it, you will be in a fully built armored rig lol . Have some fun

My point was simple, he seemed hesitant to add any mods that would add weight to the AHC, I was simply pointing out an extreme setup running AHC so that he has a better understanding of what the system can handle and simple mods to make(i.e. heavier rear springs) if he did want to add weight to the rear etc…. I said the same thing, start running trails and add mods as needed, not what looks cool. Always start with better tires

 

[Mike NXP]

My point was simple, he seemed hesitant to add any mods that would add weight to the AHC, I was simply pointing out an extreme setup running AHC so that he has a better understanding of what the system can handle and simple mods to make(i.e. heavier rear springs) if he did want to add weight to the rear etc…. I said the same thing, start running trails and add mods as needed, not what looks cool. Always start with better tires

Totally, I wasn't trying to poke at you I was just trying to show a legitimate example of situations that may call for the need for modifications. Cool to see AHC handling it with ease.


I was trying to say that based on his description he doesn't really need much to make his stock rig capable of almost anything he can throw at it. No need to think about adding bumpers and winches unless you put yourself into scenarios that call for it. Carry some basic recovery stuff, a garmin GPS incase you get totally screwed out of cell range, some solid tires and then go out there to have some fun and build it up as needed.

 

[GTV]

If you make up for the increase in weight by upgrading coils and adjusting torsion bars (making sure your pressures are correct) the AHC won't know the difference.

 

[TreatSmash]

I have a front bumper and winch, couple cranks on the torsion bars and the AHC doesn't know the difference.

 

[cryptyk]

If you make up for the increase in weight by upgrading coils and adjusting torsion bars (making sure your pressures are correct) the AHC won't know the difference

Is this really true? I was thinking about it the other day.
Stock weight is about 5,500 lbs and I've heard that AHC handles half the weight while the springs and torsion bars handle the other half. So AHC would ideally always be handling about 2,700 lbs of weight.

If you load up the truck and it weighs 7,500 lbs, I get that you can put in springs and crank the torsion bars to the point where it "erases" the extra weight and AHC will still only need to handle about 2,700 lbs. But it sure seems like the force of a 7,500 lb truck coming down hard on the dampers would be different than the weight of a 5,500 lb truck in the same situation. Do the springs and torsion bars really erase that weight from the equation even under hard compression?

 

[TreatSmash]

Is this really true? I was thinking about it the other day.
Stock weight is about 5,500 lbs and I've heard that AHC handles half the weight while the springs and torsion bars handle the other half. So AHC would ideally always be handling about 2,700 lbs of weight.

If you load up the truck and it weighs 7,500 lbs, I get that you can put in springs and crank the torsion bars to the point where it "erases" the extra weight and AHC will still only need to handle about 2,700 lbs. But it sure seems like the force of a 7,500 lb truck coming down hard on the dampers would be different than the weight of a 5,500 lb truck in the same situation. Do the springs and torsion bars really erase that weight from the equation even under hard compression?

No, there is still a limit to the amount of weight you can safely go up to. Off the top of my head I think the max gross weight (MGW) of the 100 series is 6000 lbs and I have set that as a general guideline for my weight limits. I would never go on the road with my rig at 7500lbs.

I can't speak for other, possibly more experienced members here though.

 

[Mike NXP]

Is this really true? I was thinking about it the other day.
Stock weight is about 5,500 lbs and I've heard that AHC handles half the weight while the springs and torsion bars handle the other half. So AHC would ideally always be handling about 2,700 lbs of weight.

If you load up the truck and it weighs 7,500 lbs, I get that you can put in springs and crank the torsion bars to the point where it "erases" the extra weight and AHC will still only need to handle about 2,700 lbs. But it sure seems like the force of a 7,500 lb truck coming down hard on the dampers would be different than the weight of a 5,500 lb truck in the same situation. Do the springs and torsion bars really erase that weight from the equation even under hard compression?

You wouldnt have any scenarios that add 2k lbs of weight an if you did your in the world of a much heavier build .


In my opinion you can add a few hundred lbs without any concern , no different than a truck full of fat people . Once you step over 6000 lbs you have to start considered load rating for the vehicle and tires.

If your goal is to improve light off road capabilities just get some good tires and throw some recovery gear in your trunk .

 

[cryptyk]

You wouldnt have any scenarios that add 2k lbs of weight an if you did your in the world of a much heavier build .


In my opinion you can add a few hundred lbs without any concern , no different than a truck full of fat people . Once you step over 6000 lbs you have to start considered load rating for the vehicle and tires.

If your goal is to improve light off road capabilities just get some good tires and throw some recovery gear in your trunk .

Right, I get that. I was using 7,500 as a ridiculous number to exaggerate the question.
Basically, does using springs to offset ANY amount of extra weight allow the AHC to operate normally if all it needs to suspend is the 2,700 lbs it's designed for?
For example, if you had a million pound vehicle that was appropriately designed and used springs to handle all but 2,700 lbs of its weight, could you use AHC to raise, lower, and dampen the suspension on that theoretical vehicle?

I suspect it would raise and lower just fine because AHC would literally be blind to the other 997,300 lbs. But when that thing hits a bump, it seems like the inertia generate more force on the AHC dampers even with the springs offsetting the static weight.

 

[suprarx7nut]

Is this really true? I was thinking about it the other day.
Stock weight is about 5,500 lbs and I've heard that AHC handles half the weight while the springs and torsion bars handle the other half. So AHC would ideally always be handling about 2,700 lbs of weight.

If you load up the truck and it weighs 7,500 lbs, I get that you can put in springs and crank the torsion bars to the point where it "erases" the extra weight and AHC will still only need to handle about 2,700 lbs. But it sure seems like the force of a 7,500 lb truck coming down hard on the dampers would be different than the weight of a 5,500 lb truck in the same situation. Do the springs and torsion bars really erase that weight from the equation even under hard compression?

Right, I get that. I was using 7,500 as a ridiculous number to exaggerate the question.
Basically, does using springs to offset ANY amount of extra weight allow the AHC to operate normally if all it needs to suspend is the 2,700 lbs it's designed for?
For example, if you had a million pound vehicle that was appropriately designed and used springs to handle all but 2,700 lbs of its weight, could you use AHC to raise, lower, and dampen the suspension on that theoretical vehicle?

I suspect it would raise and lower just fine because AHC would literally be blind to the other 997,300 lbs. But when that thing hits a bump, it seems like the inertia generate more force on the AHC dampers even with the springs offsetting the static weight.

This is a good question and worth understanding.

The damping for AHC is variable. Both by the manual control knob in the cabin and by the AHC ECU.

One imperfect, but perhaps helpful, way to think of the damper knob in the cabin would be "weight". It's really firmness/damping along with anti-dive/roll, etc.., but if we assume the goal is to maintain a constant damping effect, we could consider the 4 settings to represent the amount of weight they dampen. Adding weight to the car? Your 4 setting with a lot of weight might now behave like 3 with factory weight. 3 might be 2. 2 might be 1. Crank the dial to the right and you've essentially increased the weight capacity for the dampers.

I'm sure you can overwhelm the damping range of the AHC dampers, but they have a pretty wide range of adjustability from the cabin control knob and then the ECU manages additional damping. Combine the two and that means you can add quite a bit of weight and maintain sufficient damping for combined use with almost no effort. With conventional shock setups the approach to dialing in damping generally involves using high-end variable shocks or swapping a multitude of shocks in and out. You might end up with a better final matched set than AHC, but it will cost quite a bit and require a significant amount of effort.

The AHC hi-lo thought process gets a little funky because spring rates matter. The pre-load determines the standing height, but the spring rate determines how easy/hard it is for AHC to lift the car from N. Lifting 2" above N is easier if you have high spring rate springs installed. It's very difficult if you have weak springs.

Anyways, lots of potential tangents here, but suffice to say:

AHC won't be the weak link when it comes to weight. Your knowledge of the system and how to adjust it might be a limitation, but the system itself is not a limitation within any sort of reasonable bounds. @kreiten is a great example of a built 100 with little regard for weight savings that remains immensely capable and I assume far more comfortable than any other vehicle that's running Rubicon.

My build was executed with some attention given to weight only in the sense that I opted for aluminum instead of steel where possible. At no point did I opt out of any mod in the name of weight savings.

 

[hoser]

Given proper suspension mods, I would say the absolute weight limit would be 7895 lbs which is the combined axle weight rating. There is a buffer built into that rating as well.

As far as AHC plus uprated springs, it'll handle 7500 lbs but damping will be less than optimal. I'm in Sport mode all the time except for when I want the smoothest ride on a slow but bumpy section of the trail. I would love to dissect a spare Damping Force Actuator to see if it could be modified.

 

[GTV]

Taller tires, gearing to match and the ability to air down will improve the capability of any rig. The front suspension is limiting in the 100 series but the rear shares the same architecture as older/newer LC's so articulation can be improved. I'm currently planning/considering the use of LX570 coils and longer rear AHC "shocks" to increase travel.

 

[JJ_SC]

These trucks are so capable as is. It's amazing. I think tires are the most important thing to start with. Good off-road tires make a huge difference. After that, it's a slippery slope!

I have overloaded AHC several times - slowly adding and changing things to accommodate more weight. Several years ago I added the AHC lift components (AHC shock spacers.) I lifted it about 1.25". I also have stock LC springs, cranked torsion bars and the wheeler bump stops...

If I were to start over, I think I'd skip the lift. But, I think it allows me some flexibility in lowering pressures. If I'm overloaded, I can drop the lift a bit and ease the pressure. I don't know. It's in a good spot right now - until I start screwing around and adding 35s.

My highlift has helped twice when I ran over rocks I didn't see (or miscalculated.) I have a hidden winch, but I've only used it for other people. I think you can quickly learn what's going to hang you up and how to avoid it. Or, how to seek it out as you get more and more confident and built up.

Anyway, the point is, @Cantatan, get some tires with good traction and get out there. You'll quickly start to see what you want to add for the way you use your truck. It's all part of the fun.

 

[ClassyJalopy]

Given proper suspension mods, I would say the absolute weight limit would be 7895 lbs which is the combined axle weight rating. There is a buffer built into that rating as well.

As far as AHC plus uprated springs, it'll handle 7500 lbs but damping will be less than optimal. I'm in Sport mode all the time except for when I want the smoothest ride on a slow but bumpy section of the trail. I would love to dissect a spare Damping Force Actuator to see if it could be modified.

Hear this! My truck is 7800lbs when loaded to the gills with 5 passengers, 40G LRA tank, 2 steel bumpers, heavy sliders, a full steel roof rack and entirely unreasonably too much stuff on-board.
I run AHC specific TBs (re-torqued to reduce pressure) and King springs with 30mm spacers in the rear to keep pressures in range. AHC handles this well in sports mode only and becomes wallowy in the 2 softer settings.

 

[GTV]

When I was fully loaded up with stock coils and 35mm of spacer my pressures were ok but the dynamic handling left something to be desired. I could feel the tail "wag" when changing lanes, etc. It could be mitigated some by turning the knob up but it still didn't feel right. Kings springs solved that issue.

 

[dealmaker]

OP, what year is your 100? I completely disagree about lockers if you have ATRAC and want "just a little more offraod capable" that is good to go in "soft sand, snow, mud etc. only".

ATRAC works great, but IMO the biggest limiting factors on the 100 is ground clearance...it's nonexistent compared to my 4th gen 4Runner. And the cheesy plastic "engine cover" (wanna be skidplate) under the LX...wth is that? Can't imagine what running aired down does there.

My observations based on owning both an '04 V8 4Runner, and an '06 LX 470 the past 15+ years. My 4Runner has been all over Death Valley and Panamint Valley and a few places in Eastern Sierra. That's with a mild lift and slightly larger tires (265/70/17) still on stock wheels, Hanna sliders and a Shrockworks front bumper. I've barely offroaded the LX as it's the wife's pavement princess but there's no hiding the weak atributes of its poor ground clearance and poor underbelly protection.

I'm in the same boat as wanting to get my 100 at least slightly more offroadable. I'm hoping that going up to one of the largest size tires that'll fit on the factory wheels, and proper skid plates, will be all I'll need for my intended purposes of a few nights of camping/trail-running at a time. Will likely add step-sliders too. I'm hoping that the exta lift the AHC offers in 4WD will help tons on the ground clearance. Add Staun deflaters and an air tank or battery tire inflater and you should be good to go in "n soft sand, snow, mud etc. only."

 

[TreatSmash]

I made a short write up about this, but I spent a significant amount of time with the Toyota engineers at the Overland Expo and they went over my 2006 LC with me (while drinking some adult beverages) and they said the #1 upgrade they would add to my rig was ARB air lockers. In fact they said that was about the only thing.