LX570 AHC Rear Coil Spring Experiment (1 Viewer)

[GTV]

With my Gamiviti rack coming soon and an expected weight increase to follow I’ve been thinking about coil springs. I’ve decided to test out some LX570 coils to see if this is a viable alternative to Kings as they aren’t exactly cheap and there is often a wait to get your hands on a pair. I’m also the type that prefers OEM Toyota stuff as much as possible.

Some rudimentary googling shows my 2007 LC weighs in at 5425lbs and the front/rear weight distribution is 51/49. I have my third row removed and drawers installed so I’m fairly confident that my actual weight isn’t too far off from that figure. I’ve been able to travel pretty light so far.
By comparison a 2021 LX tips the scales at 6000lbs with the same f/r weight distribution.
The only thing I don’t know for sure is exactly how much weight is supported by the springs and how much is on the AHC for the 100 vs 200 series.

I found this pair on eBay for $120 shipped. They claim to be off of a 2021 LX and look virtually brand new.

The drivers side (left) spring has a blue marking, comes in at about 19” tall and has 5 1/4 wraps.
The passenger side (right) spring has a white marking, comes in at about 17” tall and also has 5 1/4 wraps.
I’ll see if I can get my mitts on a dial indicator to measure wire diameter.

I currently don’t have access to a proper garage and tools right now so I apologize that this won’t be the most scientific experiment mud has seen. I will run Techstream before and after the swap as well as take height measurements. I currently have 35mm of spacers on my original AHC LC rear coils and I will transfer them over to these springs to have an apples to apples comparison, at least to start.

Hoping to get these installed this coming weekend. I’m wide open to any other suggestions the mud brain trust has.

 

[SWCruiser]

I thought I remember reading the 100 series LC ahc springs carried more weight than the lx450 rear springs. Maybe do a search.

 

[GTV]

I thought I remember reading the 100 series LC ahc springs carried more weight than the lx450 rear springs. Maybe do a search.

Not sure what you're getting after here... I already have LC AHC springs so I'm not looking to go to a lighter spring. Unless you meant to say that LX450 springs carry more weight? Which would make sense as the 450 did not have AHC. Either way, I'll be testing these coils as they were designed by Toyota to work with AHC so theoretically the only difference is weight carrying ability.

 

[trdcorolla]

My LX has a Gamiviti Rack, sliders, 3rd row seats and some tools in the back. With 06/07 LC AHC springs (they have higher spring rates than the LX) with 30mm spacers I was right at the recommended AHC pressures (6.9F/6.2R) at stock heights (19.75 fender to center hub front and 20.5 fender to center hub rear. I'm not sure how the major height difference will do, it'll be interesting to see after you install, if I remember right, the driver side LC AHC spring is slightly taller. If your gonna run a rear bumper I don't think the 570 springs will be enough with drawers (the 200 series forum guys are using a 100 series AHC aftermarket Terrain Tamer coil on their 570's). I wonder what spring rate the Terrain Tamer coil is compared to the King's 130lbs.

 

[trdcorolla]

Not sure what you're getting after here... I already have LC AHC springs so I'm not looking to go to a lighter spring. Unless you meant to say that LX450 springs carry more weight? Which would make sense as the 450 did not have AHC. Either way, I'll be testing these coils as they were designed by Toyota to work with AHC so theoretically the only difference is weight carrying ability.

I think he meant the LX450 carries more weight, they have spring rate of 150.

 

[medtro]

I found this pair on eBay for $120 shipped. They claim to be off of a 2021 LX and look virtually brand new.

The drivers side (left) spring has a blue marking, comes in at about 19” tall and has 5 1/4 wraps.
The passenger side (right) spring has a white marking, comes in at about 17” tall and also has 5 1/4 wraps.
I’ll see if I can get my mitts on a dial indicator to measure wire diameter.

Longer spring is from the passenger side of LX570. My longer spring has red marking on it, it is also 2" longer than the other one. Wire diameter is 14mm.

 

[GTV]

Longer spring is from the passenger side of LX570. My longer spring has red marking on it, it is also 2" longer than the other one. Wire diameter is 14mm.

I presume you're doing the same thing?

That's very interesting that they're shorter on the drivers side. Any idea why that is? Do you know off hand what the wire is on 100 series springs?

 

[GTV]

My LX has a Gamiviti Rack, sliders, 3rd row seats and some tools in the back. With 06/07 LC AHC springs (they have higher spring rates than the LX) with 30mm spacers I was right at the recommended AHC pressures (6.9F/6.2R) at stock heights (19.75 fender to center hub front and 20.5 fender to center hub rear. I'm not sure how the major height difference will do, it'll be interesting to see after you install, if I remember right, the driver side LC AHC spring is slightly taller. If your gonna run a rear bumper I don't think the 570 springs will be enough with drawers (the 200 series forum guys are using a 100 series AHC aftermarket Terrain Tamer coil on their 570's). I wonder what spring rate the Terrain Tamer coil is compared to the King's 130lbs.

I do not intend to run bumpers. I'm looking for an OEM+ solution to allow me to add a small amount of weight while keeping pressures on the lower end of spec (with a small sensor lift).

 

[medtro]

I presume you're doing the same thing?

That's very interesting that they're shorter on the drivers side. Any idea why that is? Do you know off hand what the wire is on 100 series springs?

I did it a few days ago. From reading the forum, it is because LX570 fuel tank is on the right side. I put the longer spring on the driver side. LX470 springs have 12.25mm wire diameter.

The two inner springs are LX470 springs.

 

[GTV]

I did it a few days ago. From reading the forum, it is because LX570 fuel tank is on the right side. I put the longer spring on the driver side. LX470 springs have 12.25mm wire diameter.

The two inner springs are LX470 springs.

View attachment 2973153
View attachment 2973154

Any idea of the year or mileage that was on the 570 coils?
Have you done a height measurement? Run Techstream before and after?

 

[medtro]

Any idea of the year or mileage that was on the 570 coils?
Have you done a height measurement? Run Techstream before and after?

2013 LX570. Mileage unknown.

I have measurements and pressures before and after. 0.5" gains in rear height after springs swapped before starting the engine. Wheel center to fender lip height is 24.25" in N mode as soon as the engine is started. Pressures went up to 10.x front & 8.x rear. I was able to bring it down to the height I wanted (rear 21.5") with negative sensor lift at the rear, and 0.5" sensor lift at the front. Pressures are 6.8 front & 6.6 rear at this setting. It will go up another 1.5" in H mode. The behavior is totally different from King Springs.

LX570 springs have potential

Negative sensor lift with temporary extension.

 

[jsloden]

I did it a few days ago. From reading the forum, it is because LX570 fuel tank is on the right side. I put the longer spring on the driver side. LX470 springs have 12.25mm wire diameter.

The two inner springs are LX470 springs.

View attachment 2973153
View attachment 2973154

Is there a height difference in the two lx470 springs? I just purchased a set and it kinda threw me off when I realized there was almost a half inch height difference between them.

 

[medtro]

Is there a height difference in the two lx470 springs? I just purchased a set and it kinda threw me off when I realized there was almost a half inch height difference between them.

Yes, the spring with green paint mark is for driver side and it is longer.

 

[GTV]

2013 LX570. Mileage unknown.

I have measurements and pressures before and after. 0.5" gains in rear height after springs swapped before starting the engine. Wheel center to fender lip height is 24.25" in N mode as soon as the engine is started. Pressures went up to 10.x front & 8.x rear. I was able to bring it down to the height I wanted (rear 21.5") with negative sensor lift at the rear, and 0.5" sensor lift at the front. Pressures are 6.8 front & 6.6 rear at this setting. It will go up another 1.5" in H mode. The behavior is totally different from King Springs.

LX570 springs have potential

View attachment 2973334

Negative sensor lift with temporary extension.

View attachment 2973336

So maybe I'll ditch my spacers to start!

Just for some additional data points, could you share what your current approximate weight/mods are? Did you go straight from your original LX springs (no spacers) to the '13 LX springs?

That is a pretty huge gain in height. Makes me think the AHC on the 200 series carries much less of the burden than the 100 does.

 

[medtro]

So maybe I'll ditch my spacers to start!

Just for some additional data points, could you share what your current approximate weight/mods are? Did you go straight from your original LX springs (no spacers) to the '13 LX springs?

Yes, I went from LX springs with no spacers to 2013 LX570 springs. I don't know the weight. Vehicle has Ironman front bumper.

That is a pretty huge gain in height. Makes me think the AHC on the 200 series carries much less of the burden than the 100 does.

Could be. LX570 has a total of 10 globes, there are 2 globes per rear wheel.

 

[suprarx7nut]

Yes, I went from LX springs with no spacers to 2013 LX570 springs. I don't know the weight. Vehicle has Ironman front bumper.


Could be. LX570 has a total of 10 globes, there are 2 globes per rear wheel.

I was not aware of this. Sure enough, the parts diagram has the normal 4 spheres, then 6 additional "accumulators". Fascinating.

 

[IndroCruise]

I was not aware of this. Sure enough, the parts diagram has the normal 4 spheres, then 6 additional "accumulators". Fascinating.

The attachment tells the story, explains how AHC/AVS system and components work on LX570, more advanced than AHC/TEMS on LX470, part of the function on LX570 is to vary the overall 'spring rate' via the 'globes'/accumulators as well as regulate damping. This is a key difference .....

 

[LndXrsr]

Yes, the LX570 AHC/AVS is much, much more complicated than the LX470. Generally, on the 570, AHC carries less of the weight than AHC does for the 470. So the rear springs should be stiffer and a viable alternative to Kings or non-AHC 100-series LC springs for those looking to carry more weight.

Longer spring on the driver side for U.S. 100-series.

A corollary to this is that the LX570 No. 1 gas chamber (spherical one that looks similar to the 470's globes) is not a viable alternative to 470 globes, front or rear. I was hoping maybe we could improve dampening this way for heavier rigs that have upgraded to Kings, but it would actually have the opposite effect since the 570 AHC carries less weight and has a different globe to manage the dampening. The No. 1 chamber actually looks primarily to control the spring rate, interestingly.

If anyone has the actual spring rates for these LX 570 coils, I'd be interested. Will update the ABCs page with that info and the approximate reduction in MPa.

 

[GTV]

Regrettably, I'm going to have to shelve these springs for now. Surprisingly, to me at least, these coils are apparently waaay stronger than I excepted them to be. I don't have the time to fiddle **** around with this if I don't see the possibility for positive results. I think @medtro has summed it up. I'll need steel bumper type weight to take advantage of these and I do not see that in my future.

 

[LndXrsr]

Understandable. My best guess from some 570 forum digging is that the OEM 570 AHC springs fall somewhere between Kings (130lb/in) and OEM non-AHC 100-series springs (170 lb/in). That will be too much spring for a lot of builds.