‘Spring rubbers’ LX570 missing link for attitude control on normal builds (non long travel) (1 Viewer)

[grinchy]

Topic: spring rubbers and other ways to modify your base spring rate

Why: it works, it easy to install and remove, it’s cheap. And also to get this chatter out of the long travel thread, where more extensive mods are taking place

What: spring rubbers are plastic shims that you put in your spring coil. They take a percentage of a full turn of the coil out of the spring. This increase the spring constant permanently. This is analogous to getting a heavier spring, which is very difficult for the LX570. The only aftermarket springs are rear only and are 30% heavier (100 to 130 lb, roughly). Spring rubber come in a variety of durometers and (theory) can add 10, 15, 20, 25% spring rate increase.

Hypothesis: ahc can carry/maintain attitude for some portion of the vehicles weight stock, and has an additional overhead of weight it can manage with good performance. At some point, added weight (what we call mods) exceeds the ahc envelope and performance drops off quickly.

Potential solution - increase the spring constants of the springs, so the springs carry more of the modded weight, and the ahc can then be back in its management envelope.

Other solutions: a tried method (I did it to) was to replace the globes/ accumulators. I will try to provide some evidence for discussion that this might be helpful, but not as effective as spring rate increase/ spring rubbers (trucks modded to the gills or on the path to that, for example)

Here’s a picture of a spring rubber (or two)

And a picture of one installed

The LX570 takes size B in all four corners . The spring rubber needs about 70 mm (measured along the outside curve) trimmed on install to allow full wrap on front springs. Not sure what the trim would be for rear spring, the trimmed for front blue ones I moved back there were too short to cover a full wrap, and even uncut might be a bit short <edit - uncut B is also too short, probably goes 3/4 of a coil turn>

 

[grinchy]

Take a journey with me in my 215k mile LX570. I had added a rear swing bumper, put on 18” rims and 275/65r18 duratracs, put a compressor under the hood and was driving, empty, over the cascades to Nitro’s shop to get 4,88s installed. I distinctly remember on that trip thinking that the truck couldn’t get better. It cornered on rails, rode like a complete dream- attitude control in corners, braking, but also impossibly compliant over bumps and humps. It was a fun 2 1/2 hours.

35s, heavy sliders, light then heavy skids, a drawer, and a bunch of minor stuff later, the ride wasn’t as good. I changed accumulators, and it got better. Like 15% better. But I’d been to Shangri-la, and it wasn’t back to that paradise I knew from before the gears. I had reasoned that accumulators were some magic to put it right, but it had only been 18 months, and not that many miles at all - less than 10k more probably. The accumulators were most likely not the issue (hindsight man). Even with the new accumulators, I reasoned, it’s these heavy LT E 129 lod tires, and their narrow pressure window. That’s why I can only run one psi (literally, it was 36) for a reasonable ride.

A change of tires and wheels later (d flotation 121 load) and the ride was better. Almost great. A little floaty/pitchy at the psi I liked best (34) but a range of psi from 32 to 37 were ok. Still one section of road I drove most days was like sea swells, but lots of cars looked boaty there, so it must be ok.

Then I put on a bumper and winch. 120 lb added out front and it was a debacle. Ride was horrible. Very pitchy front to back, damping not working, couldn’t use comfort mode at all, was driving around in firm and still an issue. Interestingly, it got better on freeway trips. With the family. When the springs were more loaded and the total mass higher. Hmm.

So I went down a rabbit hole with what springs were available to us
100 ahc uprated springs (125? 140? - 25 to 40% stiffer)
80 rears (130? 150? - 30 to 50% stiffer)
Lots of good posts and discussions in the springs thread. But the ride went to crap when I added front weight. And these options were for rear springs. I didn’t think they’d help me much.

Then I ran across spring rubbers -> cheap. Reversible, driveway install. Worth a shot!

I have tried blue (not quite enough), and black (perfect) on the front. I put the blue ones on the rear, but I don’t think they changed much on that axle.

The ride is back to Shangri-la. Even my wife noticed. what’s more, I just put the tires up to 38 (they were down to 31 from the recent cold). I normally overfill and then set them with the gauge. Rides perfect at 38. And at 31. And at 34 (before the cold).

The increased spring rate ((particularly in front) makes a huge huge difference. Like 300%.

My hypothesis: a lot of the complaints we see regarding ahc ride attitude control can be addressed in an hour, with red or blue spring rubbers, right in your driveway. Only necessary skill is running a hacksaw to cut them down, and pulling your tire. For those running everything, you’re in black or green land.

I’m not enough versed in suspension to understand what the core issues are with ifs, rear solid, and ahc as weight is added, especially as front biased weight is added. I put this up to capture how this simple solution completely fixed my ride issues, and has it in a better than stock place (but with many many mods).

There are probably some drawbacks somewhere, if I run across them I’ll post up.

I definitely encourage the dear reader to add spring rubbers to their calculus when considering ways to address ride difficulty on an LX570, and even would go so far as to postulate that a red set could benefit a lightly or unmodded rig.

<to decode a bit, the Amazon spring rubber main supplier has four stiffnesses, which are different colors
Red - least stiff
Green - most stiff

Blue and Black are between Red and Green.

If you take one coil out of the shock (completely stiff), it would be about 25-30% stiffer. So I have estimated:
Red - 10% stiffer
Blue - 15% stiffer
Black 20% stiffer
Green - 25% stiffer
These are estimates entirely. probably in that ballpark. Maybe 5% less . . .>

 

[grinchy]

Yes, I’m running a mild sensor lift in the front.

 

[grinchy]

Free google fu
U.S. RubberShox DuraTPE Series Front-Rear Car Coil Spring Buffer Cushion/Automotive Suspension Shock Absorber Performance Booster Kit Universal Type A-F Vehicle Auto Parts (CSB,D)1.81” x 4.41” (T*D)
https://a.co/d/3wmjlCV

 

[outlaw4shrt]

Take a journey with me in my 215k mile LX570. I had added a rear swing bumper, put on 18” rims and 275/65r18 duratracs, put a compressor under the hood and was driving, empty, over the cascades to Nitro’s shop to get 4,88s installed. I distinctly remember on that trip thinking that the truck couldn’t get better. It cornered on rails, rode like a complete dream- attitude control in corners, braking, but also impossibly compliant over bumps and humps. It was a fun 2 1/2 hours.

35s, heavy sliders, light then heavy skids, a drawer, and a bunch of minor stuff later, the ride wasn’t as good. I changed accumulators, and it got better. Like 15% better. But I’d been to Shangri-la, and it wasn’t back to that paradise I knew from before the gears. I had reasoned that accumulators were some magic to put it right, but it had only been 18 months, and not that many miles at all - less than 10k more probably. The accumulators were most likely not the issue (hindsight man). Even with the new accumulators, I reasoned, it’s these heavy LT E 129 lod tires, and their narrow pressure window. That’s why I can only run one psi (literally, it was 36) for a reasonable ride.

A change of tires and wheels later (d flotation 121 load) and the ride was better. Almost great. A little floaty/pitchy at the psi I liked best (34) but a range of psi from 32 to 37 were ok. Still one section of road I drove most days was like sea swells, but lots of cars looked boaty there, so it must be ok.

Then I put on a bumper and winch. 120 lb added out front and it was a debacle. Ride was horrible. Very pitchy front to back, damping not working, couldn’t use comfort mode at all, was driving around in firm and still an issue. Interestingly, it got better on freeway trips. With the family. When the springs were more loaded and the total mass higher. Hmm.

So I went down a rabbit hole with what springs were available to us
100 ahc uprated springs (125? 140?)
80 rears (130? 150?)
Lots of good posts and discussions in the springs thread. But the ride went to crap when I added front weight. And these options were for rear springs. I didn’t think they’d help me much.

Then I ran across spring rubbers -> cheap. Reversible, driveway install. Worth a shot!

I have tried blue (not quite enough), and black (perfect) on the front. I put the blue ones on the rear, but I don’t think they changed much on that axle.

The ride is back to Shanghai-la. Even my wife noticed. what’s more, I just put the tires up to 38 (they were down to 31 from the recent cold). I normally overfill and then set them with the gauge. Rides perfect at 38. And at 31. And at 34 (before the cold).

The increased spring rate ((particularly in front) makes a huge huge difference. Like 300%.

My hypothesis: a lot of the complaints we see regarding ahc ride attitude control can be addressed in an hour, with red or blue spring rubbers, right in your driveway. Only necessary skill is running a hacksaw to cut them down, and pulling your tire. For those running everything, you’re in black or green land.

I’m not enough versed in suspension to understand what the core issues are with ifs, rear solid, and ahc as weight is added, especially as front biased weight is added. I put this up to capture how this simple solution completely fixed my ride issues, and has it in a better than stock place (but with many many mods).

There are probably some drawbacks somewhere, if I run across them I’ll post up.

I definitely encourage the dear reader to add spring rubbers to their calculus when considering ways to address ride difficulty on an LX570, and even would go so far as to postulate that a red set could benefit a lightly or unmodded rig.

After I chatted with you the last time I went ahead and bought a set of blacks for the front, still sitting on my shelf though... I do have 10mm spacers up front already and the terrain tamers with airbags in the rear, but even "unloaded" I can still get my AHC warning light to come on when hard into corners (I am still stock AHC height but I am heavy for sure).

What did you use to cut yours down 40mm?

 

[grinchy]

hacksaw. it cuts real easy, a box knife could do as well. even the black spring rubber isn't hard. I just measured my black offcut, it's 70mm. I have updated the first post.

One hint on cutting, observe the inward slope on the factory end and attempt to replicate. If you cut flush/90 degree you'll have to cut them shorter to prevent overlap

 

[Heckraiser]

Wow, first time hearing of these things (just linked over from the Long Travel thread). Thanks for posting!

 

[DirtNap]

hacksaw. it cuts real easy, a box knife could do as well. even the black spring rubber isn't hard. I just measured my black offcut, it's 67mm. I have updated the first post.

One hint on cutting, observe the inward slope on the factory end and attempt to replicate. If you cut flush/90 degree you'll have to cut them shorter to prevent overlap

So basically the circumference of the ring is slightly too big / too long, and you cut it down to fit the smaller diameter of the front coils?

 

[grinchy]

So basically the circumference of the ring is slightly too big / too long, and you cut it down to fit the smaller diameter of the front coils?

Yes. For the front coils the provided material (which is molded in a circular shape, but a little bit flexible), is long and 'overlaps' the coil wrap (interferes with itself), so you just cut some off. This is because of channel in the product which makes for a secure fit. This is also described in the install guide.

For the rear coils, I estimate the included is the right length, or a tiny bit short and no cutting would be required. I had already cut the ones I put on the rear to fit on the front . . . they install fine, but only buffer a portion of a coil wrap, so I get some percentage of a percentage of stiffening.

 

[kcjaz]

Interesting. I’m likely to have to change rear springs after my 24 gal aux tank goes in here shortly. I wonder what there’s things would do with variable rate 2721s? Would be easier that replacing with heavier constant rate spring.

 

[grinchy]

Interesting. I’m likely to have to change rear springs after my 24 gal aux tank goes in here shortly. I wonder what there’s things would do with variable rate 2721s? Would be easier that replacing with heavier constant rate spring.

you'd want to download the fit template and find out which size matches to the spacing of the 2721, or at least to the coil wrap you're targeting (since they are VR and will have variable spacing). The rubbers would then take that wrap partially out of the spring, so would definitely up the spring rate (effective). How much? Hard to say . . . The green probably would be close to taking the whole wrap out of the spring, the red maybe like 25% of that wrap.

 

[grinchy]

The three pages of calculations and conversations which led to this thread

LX 570 Custom Springs?

Turns out that partial wraps need to be counted. So any theoretical values are estimated until the exact wraps are documented.

forum.ih8mud.com

 

[grinchy]

Picture dump
The last is Rear US Driver, that gap closes down when weighted. Super easy install on that corner.

The rest are initial fit pics on the front

 

[tbisaacs]

Added to cart! I think ultimately I’ll do a preload spacer but this is a no brainer to try out.

 

[highfructose]

Does it matter where in the coil (towards the top or bottom) these are installed?

When you cut the ones for the front, is it a straight cut or did you do it at an angle?

 

[grinchy]

Does it matter where in the coil (towards the top or bottom) these are installed?

When you cut the ones for the front, is it a straight cut or did you do it at an angle?

For a normal coil like the LX570 has (not variable rate) it can go anywhere, I put it in the middle for aesthetic reasons.

Yes. You should replicate as best possible the angle that the factory cut is on. If you cut it straight that's fine, but you'll end up with a 'shorter' spring rubber as you have to cut more off to clear the full wrap. There are grooves in the spring rubber for the coils, and the grooves are more than 1/2 height. I'm not sure it would matter much regarding having the full coil wrap versus 95% of the coil wrap, but I tried to make it as close as I could.

Variable rate would pick a wrap, measure the spring rubber size for that wrap, order that size, and put it in that wrap, as it would only fit there correctly. I'd put it toward the 'heavy' side on a VR coil, to get more effective rate increase. This is really uncharted waters . . .

 

[highfructose]

For a normal coil like the LX570 has (not variable rate) it can go anywhere, I put it in the middle for aesthetic reasons.

Yes. You should replicate as best possible the angle that the factory cut is on. If you cut it straight that's fine, but you'll end up with a 'shorter' spring rubber as you have to cut more off to clear the full wrap. There are grooves in the spring rubber for the coils, and the grooves are more than 1/2 height. I'm not sure it would matter much regarding having the full coil wrap versus 95% of the coil wrap, but I tried to make it as close as I could.

Variable rate would pick a wrap, measure the spring rubber size for that wrap, order that size, and put it in that wrap, as it would only fit there correctly. I'd put it toward the 'heavy' side on a VR coil, to get more effective rate increase. This is really uncharted waters . . .

Would you mind photographing the cut you made?

 

[grinchy]

Would you mind photographing the cut you made?

sure. easiest thing to do is take the uncut item, put an angle measure on it, and mark the cut location at 70mm with that angle. it doesn't have to be precise

Looks like about 5mm shorter on the inside. Factory edge down, marked same angle on other end. Looks like my cut was more ‘straight’. It worked fine.

70mm is the outside length along the curve, not 'straight'. Just roll the ruler along the outside.

 

[kcjaz]

Variable rate would pick a wrap, measure the spring rubber size for that wrap, order that size, and put it in that wrap, as it would only fit there correctly. I'd put it toward the 'heavy' side on a VR coil, to get more effective rate increase. This is really uncharted waters . . .

For the cost of this, and potential ease, I plan on charting these waters with my 2721s. There are a lot of variables here though when you start thinking about variable coil spacing and the variable rubber stiffness. I wish I could get a big box of these things and just proceed with trial and error. I really like my 2721s but as I get heavier, and especially after I add my 24 gal aux tank, they will effectively be constant rate springs. To complete the picture, I have full BB SS skids (will likely armor my aux tank), sliders, TJM front bumper with 12000 warn winch. Dissent rear bumper with dual swings outs. I don't (yet) have drawers but I carry plastic storage tubes with a lot of stuff all the time. I eventually will add some kind of better storage system.

I need to think about where in the coils to try first. Putting the rubber shox on the light end might help keep my lift height when loaded, as I think it would make the 2721 act like at constant rate spring sooner, but I don't know how much it would add to the ultimate spring rate. Adding them to the other end would probably add the most to the spring rate. The 2721s are 270/340 spring rate and 2722s are 275, and 2723's are 350. Given where I'm headed with the weight of my rig, 2723's were going to be my next spring. Maybe I can get there with a couple pieces of rubber...

 

[grinchy]

For the cost of this, and potential ease, I plan on charting these waters with my 2721s. There are a lot of variables here though when you start thinking about variable coil spacing and the variable rubber stiffness. I wish I could get a big box of these things and just proceed with trial and error. I really like my 2721s but as I get heavier, and especially after I add my 24 gal aux tank, they will effectively be constant rate springs. To complete the picture, I have full BB SS skids (will likely armor my aux tank), sliders, TJM front bumper with 12000 warn winch. Dissent rear bumper with dual swings outs. I don't (yet) have drawers but I carry plastic storage tubes with a lot of stuff all the time. I eventually will add some kind of better storage system.

I need to think about where in the coils to try first. Putting the rubber shox on the light end might help keep my lift height when loaded, as I think it would make the 2721 act like at constant rate spring sooner, but I don't know how much it would add to the ultimate spring rate. Adding them to the other end would probably add the most to the spring rate. The 2721s are 270/340 spring rate and 2722s are 275, and 2723's are 350. Given where I'm headed with the weight of my rig, 2723's were going to be my next spring. Maybe I can get there with a couple pieces of rubber...

Yeah, it's going to be very interesting science experiement. Maybe try a narrower spring rubber on the small coils (light side), and a taller one on the wide coils (heavy side) at the same time. This might just push the entire spring up in stiffness on both measures, turning it into a 300/380.

You could do some calcs on expected results by modeling the 2721 as two separate springs, and take a full wrap out of each. That would be the max effect (green). Then dial back from there to see what you need to get the target stiffness.

I'd also suggest doing the front axle first. Maybe a red on the top and a blue on the bottom?