late night suspension musings, lifting LX570 (1 Viewer)

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i've done the sensor lift on my LX and things are generally fine, but i am quickly adding steel to the rig and i am thinking about ways to modify things to keep height and try to get the truck back to a softer ride. i have 35"s on it right now and with the sensor lift, the ride selector is on "comfort" and it rides like its in "sport" mode. so, i am thinking about trying to get a spacer at 1.5-2" so i can back off the sensor lift and get back some flexibility in the suspension mode. if i can get an inch or so total lift and the suspension selector back, i think it'd be solid. might need to add more when the bumpers arrive, but i am looking for proof of concept at this point.

looking at adjustable coil overs, i am thinking about machining a steel spacer to put under the factory front coils, maybe 30 mm to start, and add in the 20 mm factory spacers for the tops. i cant figure out any reason why that wouldnt work. cut a 30 mm doughnut 2.25" ID and 4.25" OD in a spiral (or cut a true doughnut and then cut it in half and grind/sand) and tack weld it to the coil perch. i am hoping this would give me a total of 2" lift AND let me "lower" it with the sensors just a bit to get back at least one of the shock settings.

for the rear, i am thinking a 50 mm poly/steel coil spacer, but i am not seeing anything built for the 200/LX at that height. 200s obviously just put in a 2" lift coil and shock and call it good. supposedly the sequoia has the same set up. i have seen some 50 mm spacers on ebay from some russian shop ive never heard of -

Rear coil spacers 50mm for Toyota Sequoia 2007-2017 | eBay

i am also seeing that vendors are calling 80/100/200 rear coil spacers are all the same application AND i am seeing that the 200 coils are larger ID and larger OD, which requires cutting of something to make it work. and i am not sure i have seen those applications at 50 mm anywhere, but i wouldnt expect to considering the availability of a 2" lift coil spring.

so, got me to thinking... i wonder if the stock 200/sequoia coils would be adequately stiffer to give the additional lift at some unknown height. the LX coils *should* be less stiff since the "shocks" are providing both shock behavior and height support with the coils. if i could figure out the rates for both coils, in theory i could calculate the potential lift for the 200 coil under the LX. but, i can't seem to find that anywhere, nor do i know how i could get those things measured.

so, hive mind, ive thought myself into a tangle. i am not opposed to making stuff for myself, but if i can get it done without making stuff and having spacers, i'd like to. whatcha think?
 

radman

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Are you sure you're running the correct psi on those ridge grapplers?

I'm at 7400ish pounds on my daily commute, and I float like a butterfly in comfort. How many miles on your ahc?


 
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You've come to the right place and we can help you sort this out.

What do you have in terms of buildout? How much does your rig weigh and how much sensor lift have you dialed in?

Spacer strategy can definitely work. They need to do two things however, augment for weight then augment for height, which is why it's helpful to understand overall build weight and amount of sensor lift. At some point with enough weight, you'll want to actually increase the spring rate (diff springs) rather than just pre-loading the stock springs.

My setup also rides like a cloud. I think @radman setup is probably pretty similar to yours so I'd take his lead.

Here's some more info on some of the strategies I've used
 
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well, the nittos are at 38 psi, so about 10% higher than lexus recommends, but 52 psi lower than the max tire pressure, so my thinking is the ride change is really the combination of heavier tires and maxing out the sensors. the truck definitely isnt riding bad, but it is definitely STIFF.

currently, the weight is not much more than stock on the sprung side. ive got a set of slee's sliders and my own steel under them, and of course a 35" tire in the back. so enough to be equivalent to adding another person of my weight ~200#. not much. but, coming is a set of bud built skids, a 40 gal aux tank, DOM control arms for the rear, and eventually front and rear bumpers. i am thinking 7400# is going to be the more likely weight, if not a generous underestimate. hmm... a supercharger is sounding better and better.

the sensors are maxed out. they were on the "short" side of the middle. i only got about 3/4" out of the front and 1" from the rear. less than i was expecting, for some reason.

the fluid, i am guessing, has 100k on it. so, the plan is to do a flush when i drop in the OEM front spacers. need to get the fluid and just get after it. the spacers arrived last week. did you guys see much difference with a fluid change? i am also seeing reference to swapping out accumulators as maintenance to improve handling.

ideally, i'd like to drop in the right springs rather than space things out. its figuring out what the right spring is without spending thousands "practicing" with the wrong stuff. just dont know how to figure out which! my thinking is the spacers for now, and then as weight increases, hopefully have the math and right spring worked out. you guys seen any resources around springs?
 

afgman786

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So points and questions as well to get more info and others input..

front spacer:
- with your front spacer if you go for 2inch you'll need to have bolts on top of that spacer to bolt down to the tower. A factory front spacer already drops the threads available to only showing maybe 5 threads after the but is torqued down.
- will too much of a front spacer not make your shock bottom out? I know this is the case with normal shocks, not sure how the AHC shock fully works. You could extend the factory bump stop on the LCA to not have your shock bottom out.

rear lift:
- Sequoia is IRS so the coil bucket might be different.
- OME offers trim spacers you could stack on the coils to get to the height you want. They don't offer 50mm, but do offer 10mm, 15mm, and I believe 20mm that you can stack on the coil. You also have Trail Tailor that offers 30mm rear coil spacer.
 

afgman786

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To your point on springs. If you're adding all that weight, won't OME or Tough Dog springs work? That would take load off AHC if they do fit.

LX guys is this feasible?
 

tbisaacs

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To your point on springs. If you're adding all that weight, won't OME or Tough Dog springs work? That would take load off AHC if they do fit.

LX guys is this feasible?

The Spring rate would likely be too high.
 
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What specific tire size are you running? 38 PSI sounds in the ballpark and shouldn't feel that stiff with a 35s? @gaijin , our RCTIP guru can help you dial it in.

Does sound like you need a flush. Many have commented that it noticiably improves ride quality.

For the front suspension, I would caution adding too much spacer to the tops of the coilover as @afgman786 points out. We don't know what the limit is before the front coilover becomes the bottom out limiter and that would be disastrous. Depending on how much sensor lift you want to run, the front OEM spacer is likely all you need. Other than front armor which is easily within AHCs ability, most of the added weight is going to be at the rear axle. If you could come up with a custom 10-mm coil spacer, that could work well.

Rear, I think you're on the right track with about 40-50mm spacer with the amount of weight you'll ultimately have. That sequoia spacer won't work right out of the box as the centering inner lip diameter looks like it won't fit over the stock coil isolator. It's possible it would fit above the isolator between the body. May need some machining of material.

Another couple strategies
1) Use large 30mm coil spacer. Then augment further with airbags and it would only need mild pressure
2) Use a normal spring from a LC100. I think dropping in a normal LC200 spring would be too much spring rate. Need something more tender than that.

Sensor lift, you can get more with the sensor offset utility in techstream. @radman has a good guide for it
 
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front spacer:
- with your front spacer if you go for 2inch you'll need to have bolts on top of that spacer to bolt down to the tower. A factory front spacer already drops the threads available to only showing maybe 5 threads after the but is torqued down.
- will too much of a front spacer not make your shock bottom out? I know this is the case with normal shocks, not sure how the AHC shock fully works. You could extend the factory bump stop on the LCA to not have your shock bottom out.

i won't be going more than the 20 mm toyota spacer for the TOP of the front coils. that bolt situation was exactly what i was concerned about. i was considering machining a taller spacer that i could put studs into with recessed pockets like a wheel spacer to get more height up front, but i realized that would still require finding a way to get the fluid connection in there with no issue, and i'd need to sort out some bump stops if i went much more than 20 mm. my thinking on the additional spacer was to put it between the BOTTOM of the spring and the spring perch on the shock tube to preload the spring and take some of the work off the AHC in addition to the top 20 mm spacer. a bump stop extension might still be useful.

rear lift:
- Sequoia is IRS so the coil bucket might be different.
- OME offers trim spacers you could stack on the coils to get to the height you want. They don't offer 50mm, but do offer 10mm, 15mm, and I believe 20mm that you can stack on the coil. You also have Trail Tailor that offers 30mm rear coil spacer.

yeah, i haven't seen any consistent descriptions or applications on the sequoia stuff. i am inclined to skip that whole path on principal alone. i was unaware OME offered spacers, so i will check that out. stacking them seems like a terrible idea, but i've never used spacers before, so that may stem from unfamiliarity at this point. the TT unit requires carving to fit, it's not large enough for the 200 coils. not a fan of cutting off a quarter inch by free hand to get that right.

i am of the mind that any 200 series spring is probably going to be too high a spring rate for the LX. but, i honestly don't know how much of the suspension load is handled by the AHC system, so that may be a misguided guess. i haven't found a techstream purchase that can be had without a CD/DVD drive for a mac, so i haven't pursued that path yet (would like to if anyone has a lead) to start mathing to figure out how much load it gets. seems simple enough to figure out - AHC psi vs height, move height, find out AHC psi again, draw slope. my original thinking of putting in some factory 200 springs that someone else has removed for their lift just to see how that goes seems like a cheap and reasonable place to start. if the AHC only takes up 10-20% of the load, a stock height 200 spring and a sensor drop might get me in the right ballpark is my thinking. maybe that's an experiment worth pursuing.

What specific tire size are you running? 38 PSI sounds in the ballpark and shouldn't feel that stiff with a 35s? @gaijin , our RCTIP guru can help you dial it in.

the nittos are 35x11.50x20. factory recommended is 32-34 psi from the sources i've seen, so my thinking is the stiffness is all in the sensor stuff. i do think a flush is worth the effort considering the truck never left the pavement before i bought it and the soccer mom who owned it before me was unaware of the maintenance she needed to be doing. first thing i did was drop in a serpentine belt as the original was all cracked out!

For the front suspension, I would caution adding too much spacer to the tops of the coilover as @afgman786 points out. We don't know what the limit is before the front coilover becomes the bottom out limiter and that would be disastrous. Depending on how much sensor lift you want to run, the front OEM spacer is likely all you need. Other than front armor which is easily within AHCs ability, most of the added weight is going to be at the rear axle. If you could come up with a custom 10-mm coil spacer, that could work well.

absolutely. i don't want more than the factory 20 mm on the top of those coils. my thinking on more spacer was just to preload the coils from the bottom, which shouldn't change the total cycle stroke much if i am taking load off of the AHC. but i obviously don't know how much preloading will translate into additional height without trying it and measuring AHC pressure, so this is all arm waving speculation at this point. good point on the load mostly in the rear. helpful enough, that seems like the easier part of the system to tinker with. hell, at this point, maybe the 20 mm up front gets me where i need to be with no issues at all. the last of the front will be a bumper and probably a winch eventually, which is less than a Slee rear bumper from what I can tell.


my impression is that there haven't been many vocal LX owners that have gone down this path yet with the 570 so far. i bet as pricing comes down and people stop freaking out about the AHC system and see it for how badass it actually is, there will be more people tinkering with this stuff and ideas will come. i am glad to be at the tip of the spear on this one if i can be helpful.

Another couple strategies
1) Use large 30mm coil spacer. Then augment further with airbags and it would only need mild pressure
2) Use a normal spring from a LC100. I think dropping in a normal LC200 spring would be too much spring rate. Need something more tender than that.

Sensor lift, you can get more with the sensor offset utility in techstream. @radman has a good guide for it

airbags and a 30 mm... that's something i was hoping to avoid. i guess it's not a terrible option, but i hate the idea of having another system to manage in there. in the tool bag, though.

the LC100 springs are a smaller diameter, aren't they?

i definitely want to sort out some techstream solution. does anyone offer it in an app? i haven't seen it for apple products at this point, nor have i seen it available for mac laptops or without an optical drive. i was hoping to measure pressures through all of this, but i was too eager to wait around to find a techstream solution before i put the tires on.
 

nwfl4runner

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Rear is easier to start with. Generally speaking if you discharge all AHC pressure the rear is sitting almost on bump stops. Gives you an idea how low the spring rate in the rear actually is. My concern with swapping springs is that we don’t know how the system is designed to handle a new spring rate. If your plan is to go super heavy then eliminate AHC. Otherwise aren’t you augmenting a small but integral part of the system?

I think if you modify the spring rate you need to change the AHC response to that spring rate and I don’t know what that is.

Up front, we can do the same - discharge AHC and it rests essentially on the bumps. Now you’ll know how far from coil bind you are. I believe compressed length of the shock is 17” when I measured. I imagine any spacer of any real size will require a dropped bump mount.
 

afgman786

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@stumpy putting at the bottom for the front would still result in the shock being the bump stop with the way I'm picturing it in my head.

Also to your point of stacking, its not bad at all. I stacked 2 10mm at the rear on each side. Here's a picture of what it looks like.
20201018_141046.jpg
 
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Rear is easier to start with. Generally speaking if you discharge all AHC pressure the rear is sitting almost on bump stops. Gives you an idea how low the spring rate in the rear actually is. My concern with swapping springs is that we don’t know how the system is designed to handle a new spring rate. If your plan is to go super heavy then eliminate AHC. Otherwise aren’t you augmenting a small but integral part of the system?

that's my concern, too. i'd be perfectly happy with the same spring rate with an additional 2" of height. found a custom coil maker on line that i submitted an inquiry to, so maybe they can help figure that out. if the AHC drained drops the rig to the bump stops, the AHC is MUCH more important to suspension management than i realized. a stock LC coil is probably way too much spring to bother with AHC, so probably not the way i want to go.

@afgman786, if a spacer is put between the coil and the mount up front, it's more likely that the shock would become the droop-limiter than the bump stop. and considering how close the upper control arms are to the coils, it may be that would be a droop-limiter before the shock dropped out. definitely worth investigating the suspension travel to be sure i am not setting myself up for an unwanted expensive suspension experiment. where did you get those spacers? i am not finding them anywhere! good to see stacking in action. it may be the cheapest way to get an easy solution. i'll think about that one more seriously.
 

afgman786

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that's my concern, too. i'd be perfectly happy with the same spring rate with an additional 2" of height. found a custom coil maker on line that i submitted an inquiry to, so maybe they can help figure that out. if the AHC drained drops the rig to the bump stops, the AHC is MUCH more important to suspension management than i realized. a stock LC coil is probably way too much spring to bother with AHC, so probably not the way i want to go.

@afgman786, if a spacer is put between the coil and the mount up front, it's more likely that the shock would become the droop-limiter than the bump stop. and considering how close the upper control arms are to the coils, it may be that would be a droop-limiter before the shock dropped out. definitely worth investigating the suspension travel to be sure i am not setting myself up for an unwanted expensive suspension experiment. where did you get those spacers? i am not finding them anywhere! good to see stacking in action. it may be the cheapest way to get an easy solution. i'll think about that one more seriously.

I purchased my rear spacers from cruiser outfitters. Good people and lots of knowledge
 
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@afgman786, if a spacer is put between the coil and the mount up front, it's more likely that the shock would become the droop-limiter than the bump stop. and considering how close the upper control arms are to the coils, it may be that would be a droop-limiter before the shock dropped out. definitely worth investigating the suspension travel to be sure i am not setting myself up for an unwanted expensive suspension experiment. where did you get those spacers? i am not finding them anywhere! good to see stacking in action. it may be the cheapest way to get an easy solution. i'll think about that one more seriously.

On the front axle, the shock is the droop limiter, so no worries there. The OEM shock spacer has the nice benefit of increasing droop travel about 1" which adds to the overall suspension travel.

Stacking to some extent in the rear is fine. The large center isolator/bump stop will keep the rings centered unless it gets to the tapered part.
1603051448536.png
 
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gaijin

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the nittos are 35x11.50x20. factory recommended is 32-34 psi from the sources i've seen, so my thinking is the stiffness is all in the sensor stuff.

FYI, the Recommended Cold Tire Inflation Pressure (RCTIP) for those 35X11.50R20LT tires on your LX570 is 37psi F/R.

HTH
 

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