Long Travel AHC (2 Viewers)

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So we're not talking past each other, the advertised lift of spacers is not the same dimension of the spacer thickness because of the suspension motion ratio.

Too bad most advertisement don't list the real spacer thickness. At least we can confirm the 1.5" lift is a 24mm spacer. So motion ratio for a Tundra is about 2:3.
Good point! My response to that EBay spacer was based on a thickness of 1.5”, not 24mm. So I don’t know if I should delete my previous response or hope that everyone reads all these posts.
 
It's all good. It was more to clarify the discussion between spinedoc44 and 1UZJ80N60. :)
 
This is kind of perfect actually. Got a link?

I believe they are indeed 19mils back there. And rotating the tube is no biggy.

Thanks! Did not know about these.
I'm having trouble finding them on the Japan 4x4 site... I don't know if they are still available... Here's where I bought them, but anyone could fab something like this:JAPAN4x4 - http://japan4x4.com/?transactionid=4ce1f0cd5f750e11b01f6887690314671585a548

I bought them for about ~$200 USD shipped from Japan, maybe 8 years ago (they also came with a front set on the 100 series that's a bit more complex).

Try contacting Dave Stedman: stedman@japan4x4.com ... apparently he was still selling them in 2020... not sure if he will sell rear's only, but it's worth asking.
 
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I think a diff drop can be used to help reduce the CV angles...Very cheap modification on a 200 series.

 
So we're not talking past each other, the advertised lift of spacers is not the same dimension of the spacer thickness because of the suspension motion ratio.

Too bad most advertisement don't list the real spacer thickness. At least we can confirm the 1.5" lift is a 24mm spacer. So motion ratio for a Tundra is about 2:3.
Yes! Coming from the Tundra world I was aware of this point but thank you for the clarification.

To summarize: The above spacer can be installed without disassembly of the coilover but does require the AHC line to be rerouted. If one desires they can also remove the OEM sway bar without having to worry (much) about CV detonation.

My goal is maximum droop + maximum affordability. LOL

Am I tracking correctly?
 
Thinking out loud as @grinchy brought up a topic I've been noodling on for awhile.

Sensor Lift and Harsh Ride​

AHC is supported by two elements: 1) coil spring that is linear rate 2) hydraulic accumulator that is progressive rate. Combined would be overall progressive rate. The reason that some AHC sensor lifts ride harsh is due a few possibilities.
  1. Too much load on the hydraulic accumulator pushing the accumulator into a very high rate region (i.e. too much spring rate).
  2. Too much load potentially into bottoming out of the accumulator if worn.
  3. Too little droop travel and articulation
  4. EDIT: Too much weight or sensor lift in combination with above.
Counterintuitive, but because of #1, adding pre-load to the linear spring may help actually soften the overall AHC spring rate improving ride.


Long Travel wants Lower Spring Rates​

Adding pre-load to the stock AHC springs, front or rear, is potentially a better solution than increasing spring rate with aftermarket springs to address load. The premise is long travel suspensions work better with lower rates springs to maximize articulation. The focus on spring rates is often to support a load. I think it's intuitively understood that higher spring rates can limit compression. But it's just as important to consider rates and how they effect droop travel. A higher spring rate coil spring gets unloaded far quicker in droop travel which may also limit articulation in that direction.

As an example, assuming stock 105 lb/in rear springs. Let's assume at neutral ride height, a coil is supporting 600lbs. By definition, that would be compressed a bit more than 6". For every 1" travel in droop, the spring will push back with 105 lbs less by definition.. So say 3" droop, and now the spring pushes down with 285lbs at that extended position.

Doing the same math for a higher rate linear spring, let's say something at 150 lbs/in. At neutral ride height, supporting 600lbs. After 3" droop travel * 150 lbs/in, it's only pushing down with 150lbs of force at that extended position.

Trying to convince long travel peeps to stay with soft coils! If there are load concerns, use pre-load rather than higher rate springs.
EDIT: That said, if you really have that much more installed weight, some increase in spring rate may be called for, balanced with above.

Is it as simple as this? In your example, if the 105lb springs are carrying 600 lbs and are compressed 6', then the globes are carrying the rest of the weight, whatever that is. If you installed 150lb springs, because of height leveling, the spring is going to be compressed the same 6", assuming gravity can account for that, so there will now be 900 lbs (I didn't do any spring calculations here, just assuming it's linear) on the springs and less weight on the AHC globes.

I don't think this changes the story, as far are not wanting to over spring your AHC system. But it seems like it would be mostly because you want to have the proper spring amount to let AHC be able to be dynamic. Too little or too much load obviously leading to lack of adjustability. I think @grinchy mentioned the fact that really any weight you add, you would want to account for at the springs, so that AHC carries the same weight it was designed to carry.

Just to finish the thought,

In a non AHC truck 150' spring would only compress 4" (assuming 600lbs was all the weight to carry). Then, like you said, if you droop 3" there is only 150lbs from the spring.


Edit: Adding to the discussion, and maybe the answer to what i was saying. The above is assuming the springs are the same length. If the 150lb spring is 2" shorter than the 105lb spring, then what @TeCKis300 holds. So, i guess a critical component to the conversation, and it was mentioned so I'm not suggesting I'm adding anything here, is that the combination of a longer preloaded soft spring, is better than a shorter heavier spring.
 
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I think I would just qualify by saying you can max DROOP but not necessarily travel. You are still dealing with shock compression as a factor with the factory bump stop. I believe @TeCKis300 measured the amount of shaft left when adding his additional spacer so as to keep his bump stops in the same place. Going beyond that you're robbing compression for droop. Also, need to consider whether you will be able to articulate fully within the range of your vehicle weight. I just harp on this as we're discussing long (i.e., extended) travel.

Yes thanks, its crucial to mention IFS caveats still apply.

However, being that the shock travel is restricted in stock form, and the shock lengths already have room to spare in both droop and compression (with the bonus of variable lenghtening as needed), you should still gain articulation aside from just being an adjustment of neutral position in the stroke (like you said).

How much gain though idk, but with having no real CV correction mods outside of tundra conversion being in play, its still something. And keep in mind sway bar needs to be adjusted too to free up some additional play.

AHC on tundra kit is probably as good as it gets in my mind for the LX and in my mind a fantastic overall suspension, with oem ride, and height adjustment.

That’s still pretty awesome.

And if anyone wants more pre load, ahem @MTKID, they can disassemble again 😂, and slip the billet shim UNDER the shock top collar stud mount.
 
One thing that's been touched on, but I think kind of confuses some folks is the limiting factor of the shock vs. the sway bar.
On a stock AHC setup there is no "advantage" to disconnecting the sway bar as far as droop is concerned. The shock will reach it's full extension before the sway bar becomes a limiter. If you place the suspension in full droop and unbolt the lower shock mount, there is a little over an inch of additional travel before the sway bar then binds. So you would need a spacer that gains that same inch of droop before the sway bar becomes the limiter. Of course at that point you still have to address the CVs, tie rods, etc.

This may be obvious to most, but I've had several conversations with individuals that seem to think disconnecting the front sway bar will provide instant additional travel. On a stock AHC setup I don't believe this to be true.

On a separate note, in regards to driving difference without the sway bar, I was in the camp of believing that I had to keep the front sway bar intact or the road handling would be adversely impacted. (Even though @MTKID had already told me otherwise 😁). Long story short, I was driving around town for a month with the front sway bar "disconnected" and didn't even notice the difference. 😬

IMG_1179BFE32B5D-1.jpeg
 
One thing that's been touched on, but I think kind of confuses some folks is the limiting factor of the shock vs. the sway bar.
On a stock AHC setup there is no "advantage" to disconnecting the sway bar as far as droop is concerned. The shock will reach it's full extension before the sway bar becomes a limiter. If you place the suspension in full droop and unbolt the lower shock mount, there is a little over an inch of additional travel before the sway bar then binds. So you would need a spacer that gains that same inch of droop before the sway bar becomes the limiter. Of course at that point you still have to address the CVs, tie rods, etc.

This may be obvious to most, but I've had several conversations with individuals that seem to think disconnecting the front sway bar will provide instant additional travel. On a stock AHC setup I don't believe this to be true.

On a separate note, in regards to driving difference without the sway bar, I was in the camp of believing that I had to keep the front sway bar intact or the road handling would be adversely impacted. (Even though @MTKID had already told me otherwise 😁). Long story short, I was driving around town for a month with the front sway bar "disconnected" and didn't even notice the difference. 😬

View attachment 3187452

That’s the opposite of my and others observations though. And also your link snapping…

Are you sure? When i undid my front end, removing link drooped another inch or two. Did you perform your testing with your control arms unbound?

The shock seems to extend well past CV bind point and sway bar tension.
 
My turn.


Currently stuck waiting for the UCA bolt to un-seize itself out of the spindle, i dont want to hammer on my nice new arm.
I have the lower cam bolts loose, and the sway lower link bolt out, and its loose in its cradle out of tension.
Seems like the upper ball joint is bound now, and that could be what i experienced during that install.
Once its out, i will see if the shock wants to give any more and remeasure.
 
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One thing that's been touched on, but I think kind of confuses some folks is the limiting factor of the shock vs. the sway bar.
On a stock AHC setup there is no "advantage" to disconnecting the sway bar as far as droop is concerned. The shock will reach it's full extension before the sway bar becomes a limiter. If you place the suspension in full droop and unbolt the lower shock mount, there is a little over an inch of additional travel before the sway bar then binds. So you would need a spacer that gains that same inch of droop before the sway bar becomes the limiter. Of course at that point you still have to address the CVs, tie rods, etc.

This may be obvious to most, but I've had several conversations with individuals that seem to think disconnecting the front sway bar will provide instant additional travel. On a stock AHC setup I don't believe this to be true.

On a separate note, in regards to driving difference without the sway bar, I was in the camp of believing that I had to keep the front sway bar intact or the road handling would be adversely impacted. (Even though @MTKID had already told me otherwise 😁). Long story short, I was driving around town for a month with the front sway bar "disconnected" and didn't even notice the difference. 😬

View attachment 3187452
I love not having a front sway bar especially when paired with over 1 inch of added droop and slow moving articulation. As mentioned earlier, any point I feel unstable I switch to sport mode and that gives me some level of comfort back.

Also, your points are important. Removing the sway bar capitalizes on a spacer that ads more that 1 inch of droop with stock control arms. The balancing act is aligning those two measurements. Not grenadeing a CV and eliminating any UCA interference.

Honestly, I’m pretty reckless with My attempts. I don’t care if a lost CV is the deciding factor in “I took it to far”
 
So… the front accumulators/globes are “stiffer” (maybe not the exact phrase) than the rears? What would be the downside of just trying to install a pair on the rear for science?
 
So… the front accumulators/globes are “stiffer” (maybe not the exact phrase) than the rears? What would be the downside of just trying to install a pair on the rear for science?
That’s interesting… lets get those 600 shocks mounted first ;)
 
That’s interesting… lets get those 600 shocks mounted first ;)
I have an old set of fronts and rears here. Any harm in tossing the old 224k mile fronts on the back? Aside from not being able to isolate our testing of the shocks for any strange characteristics.
 
Not sure who this is but this goes over it well.

 
I have an old set of fronts and rears here. Any harm in tossing the old 224k mile fronts on the back? Aside from not being able to isolate our testing of the shocks for any strange characteristics.
I think you’ll get better results with spring rubbers to increase spring rate.
I’m beginning to think about how this all fits together over time, and really wondering if what I really needed when I did the accumulators was actually stiffer springs.
I remember post accumulators install that the ride was firmer, attitude control was better, but it was just 10 or 20% better. Noticeable, not remarkable. Passengers wouldn’t notice, too subtle.

Spring rubbers (I saw biggest result on the front post bumper, but that will differ based on your need), are like 300% better. Even my wife noticed. I really have to try to get the attitude out of whack now, like floor it on a downhill before it flattens out, and even then I get one jounce and back to smooth sailing, very remarkable.
These things are like $40 and take less than an hour to install.
 
I think you’ll get better results with spring rubbers to increase spring rate.
I’m beginning to think about how this all fits together over time, and really wondering if what I really needed when I did the accumulators was actually stiffer springs.
I remember post accumulators install that the ride was firmer, attitude control was better, but it was just 10 or 20% better. Noticeable, not remarkable. Passengers wouldn’t notice, too subtle.

Spring rubbers (I saw biggest result on the front post bumper, but that will differ based on your need), are like 300% better. Even my wife noticed. I really have to try to get the attitude out of whack now, like floor it on a downhill before it flattens out, and even then I get one jounce and back to smooth sailing, very remarkable.
These things are like $40 and take less than an hour to install.
Have you linked them in this thread yet, or just your build thread? I love the simplicity and ease of install and swapping 👌🏼
 

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