cgawelko

You can get Sensen struts from Rockauto for $18 a piece - plus some shipping.

McPierson

iTrader: (3)

So I went into this expecting some things that turned out to be incorrect. I'm going to refrain from discussing ride quality related to the spring choices because it turned out I had two bad front lower ball-joints and old shocks.

INTRO:
I created this fixture to hold the shock/spring assembly in the load from. The frame is good for up to 10,000lb of force. I got up to 2,000lb. This means the load measured is fairly accurate (within the working range of this equipment).



FRONT:

I did the fronts first since I knew I had something loose (turned out to be two ball-joints.




RESULTS:


The front springs operate in the 1400 lb range 1" of spring movement is about 1.5" of wheel movement. Bump stops at 2.7 inches of spring travel.

Anyone can determine their own results from this graph, but I'll summarize.

Preload:
OEM 860 lb
Tanabe 410 lb
H&R 230 lb

Each front shock showed a decrease in stiffness around 1.2 inches of travel. I'll report the stiffness for both ranges.

Stiffness in the 0.2 - 1 inch range:
OEM 540 lb/in
Tanabe 640 lb/in
H&R 615 lb/in

Stiffness in the 1.4 - 2.6 inch range:
OEM 250 lb/in
Tanabe 340 lb/in
H&R 405 lb/in

This shows that the H&R springs are actually lower than Tanabe. I also measured this on the car.

Based on this graph and the correlated 1400 lb operating load and 1 to 1.5" ratio we can determine lowering amounts.

At 1400 lb Tanabe has 1.05" more movement than OEM. So they lower 1.6"
At 1400 lb H&R has 1.4" more movement than OEM. So they lower 2.1"

I used the lower Bilstein mount which lowers the spring 0.4" and lowers the car 0.6 inches. So my car ended up 1.1" lower than with the Tanabe springs! That was pretty cool. This was verified on the car also.


REAR:
The rear are in the 800 lb range. 1" of spring movement is about 1.3" of wheel movement.



Preload:
OEM 430 lb
Tanabe 130 lb
H&R 50 lb

The rear lowering springs show some progressive behavior. I see a bit of a kink at about 2.4 inches so I’ll report the spring stiffness of the lower and upper range, though they are similar and identical for the OEM. Bump stops at 4.7 inches.
Stiffness in the 0.2 to 2 inch range:
OEM 145 lb/in
Tanabe 160 lb/in
H&R 170 lb/in

Stiffness in the 3.5 to 4.5 inch range:
OEM 145 lb/in
Tanabe 195 lb/in
H&R 230 lb/in

Here at the operating range the H&Rs only seem to be 0.2” more shock travel than the Tanabe. With the addition of 0.4” from the Bilstein shock and the 1 to 1.3” ratio. That lowered the car 0.8 inches. This was also verified on the car.

PRELOAD ISSUE:
Running the Bilstein shocks on the lower perch setting with H&R springs creates a preload problem… there is none.

What I did was substitute the spacer from Bilstein with a hardened washer. The thickness of this washer is critical to ensuring that the top-hat actually bears on the washer. There is a flat on either side of the shock that interfaces with a flat in the top-hat. The moral of the story is that YOU will need to measure your own to be sure that it’s all good. I got mine just thicker.

I have the spacer and the new hardened washer on the shaft in this pic. You’ll figure it out.


I didn’t take a before picture, but here are a few that I’ve taken over the years.
OEM:


TANABE:



H&R + Bilstein (0.6”):


OEM + Bilstein (0.6" drop)


Conclusions:

LOWERING
FRONT:
OEM 0
Tanabe 1.6"
H&R 2.1"
Bilstein 0.6"

REAR:
OEM 0
Tanabe 2.1"
H&R 2.3"
Bilstein 0.5"

So there is a huge finding... the H&R springs are lower with or without the Bilstein shocks. This flies in the face of every recommendation that I've heard on this forum about springs. "Tanabe springs blow shock because they are lower/softer..." Tanabe aren't lower and they have very similar stiffness to H&R. Almost the exact same behavior. One just has less preload...

The car rides much better on Bilsteins. I’m sure some of that is due to the shocks and the ball-joints. I’m just glad to get the car a bit lower too… Since this all goes against the forum history I feel like H&R may have changed their design. I can’t be sure unless I test some other H&Rs.

I hope this helps some people make better informed decisions.

Matt

EDIT: I eventually swapped back to the OEM springs since the use for the car turned into a backup/snow condition and tires are much cheaper on the OEM wheels than the 18". I dragged on speed-bumps and rubbed a bit on turns. Back to the rolling couch

PureDrifter

iTrader: (10)

Thank you for taking the time and energy to do this test.

That said, I feel there are several flaws in your testing methodology.
First off, you didn't seem to do a spring-only rate test. You're testing what is essentially incomplete wheel rate by using the shock and "2000 pounds".

I urge you to repeat the tests with just the springs, measuring between 20-70% compression (vs. OAL).

calculating the motion ratio, wheel rate, and then working backwards to calculate spring rate and see where it is against your (new) actual figure would be interesting as well.


Here's a couple resources to use for doing the math:
http://eibach.com/america/en/motorsp...sion-worksheet
http://www.hypercoils.com/spring-calculator

McPierson

iTrader: (3)

Several flaws... I guess that's a joke?

If you want the wheel rates, a way you could contribute to this thread would be to do the math in your link to solve for the wheel rate using actual spring rates that I just reported...

Or if your interested in the between 20% and 70% values you could just pull them of the chart... it's all there....

I guess you skipped over the "Motion Ratio" part of my post... the post was pretty long. Imagine how much time I put into making this and compare that with the time you spent reading and I think you'll see why the joke wasn't very funny.

Stroock639

first off, thank you very much for taking the time, energy, resources to do this test. i would never complain about free information, however i also feel that this test isn't entirely conclusive.

i don't think PD was "making a joke" but i think he, like i was also slightly misled by this test. including the shock absorber in the test instead of just the spring surely effects the results, which by the way i'm slightly confused by, unless i'm reading something wrong. (front springs) so it took 1000 lb to make the oem spring move 0.4 inches, but the H&R moved that much with only 400 lb? wouldn't a spring that moves the same distance with less weight needed make it less stiff? the H&R's are definitely the stiffer springs though, which was confirmed in the numbers

what i basically took away from this is that the H&R's with the bilsteins on their lowest setting is lower than the tanabe's with stock struts? wouldn't that be obvious since the bilsteins lower the car additionally? i don't feel that that's any sort of conclusive result that needed to be worked out... why not put the H&R's on stock struts to get a better comparison to the tanabes on stock struts?

again, BIG thanks for doing this test, and nobody has the right to talk ****** until they do their own test, but i too feel this wasn't as conclusive as it could've been

McPierson

iTrader: (3)

The springs are on the old blown shock. There was essentially no resistance provided by the shock. It's also the perfect way to test the system since the top-hat and the lower perch are what actually go in the car. I guess I could run the test with just the shock to help prove that to you, but I'm not going to. I pushed the shock down with my hand and it didn't return... i.e. negligible.

The preload thing you'll just need to look into, but thing about it like this. When removing the OEM rear spring from the shock I had to compress the crap out of it. To put the H&R spring on the shock I didn't have to compress it at all...

I should have added a Conclusions: section.

LOWERING
FRONT:
OEM 0
Tanabe 1.6"
H&R 2.1"
Bilstein 0.6"

REAR:
OEM 0
Tanabe 2.1"
H&R 2.3"
Bilstein 0.5"

So there is a huge finding... the H&R springs are lower with or without the Bilstein shocks. This flies in the face of every recommendation that I've heard on this forum about springs. "Tanabe springs blow shock because they are lower/softer..." Tanabe aren't lower and they have very similar stiffness to H&R. Almost the exact same behavior. One just has less preload...

PureDrifter

iTrader: (10)

A reminder to everyone: We do not tolerate personal attacks on ClubLexus, towards moderators or any other members. Respectful discussion and disagreement is perfectly fine as long as it remains as such.

McPierson:
I maintain that your methodology in including the shock and it's positioning in your testing is flawed. The shock not returning simply indicates it has no charge, if it took any effort to push the shock piston into the body at all and if it was anything other than perfectly linear, it compromises your results.

Additionally, your results are at odds with what has been proven time and time again that the tanabe are both a softer ride (subjective) and lower the car more (~2"+) (objective) than the H&R springs. Hence both manufacturers rate their respective drop levels.

I don't dispute that it is possible that with the bilstein shocks set to their lowest perch it is possible for the H&Rs to be lower than the Tanabe, but as I have not done it and don't know anyone who has (tanabe on drop perch bilsteins) I can't make a definitive statement.

Tanabe's official spring rate for the DF210 is 6kg/mm front and 3.3kg/mm rear. OAL is longer than the H&R but less than stock. Listed lowering is ~1.3-1.6in.

H&R's official spring rate for the UCF20 springs is not publicly released as it is a progressive spring rate that is stiffer than standard.
Per H&R they DO NOT recommend using the sport spring on any spring perch setting other than stock. IE- using the H&R spring with the "lower" bilstein perch is NOT recommended due to the progressive nature of the spring and the reduced OAL vs. stock. Listed lowering is 1.0 inches. (yes, I called H&R and asked when I couldn't find a spring-rate listed.)


Draw your own conclusions, but go ahead and put both sets on your car with the same spring and the same damper and OE perch level, drive the car a few days to let everything settle then measure, dollars to donuts like we've seen numerous times the Tanabe will be the lowest.

McPierson

iTrader: (3)

[CAPS for emphasis, not volume] The shocks would effect each spring the EXACT SAME. So that can't explain why the H&R's are lower. With testing there's ALWAYS a compromise. If I didn't use the shock and instead fabricated a lower perch to place in the load frame, I would have been scared to death that the spring would jump out of the load frame and wreck something. Or that the lower perch didn't allow enough torsional movement... so no matter what someone can come along and say "That's not right." The question is what is significant. 10lb to compress a shock in my opinion is negligible compared with 800lb to compress a spring.

The Bilstein thing is simple. The 0.4" lowering perches lower the front 0.6" and the rear 0.5". My car was more than 1" lower in the front and 3/4" lower in the back going from Tanabe to H&R springs...

The car is the proof. The testing won't be debunked. It was performed on a research grade of equipment, at a university, by a Professional Engineering with a PhD and significant experience performing load tests ranging from a few pounds to a self designed 1million pound loading mechanism...

Sorry to disappoint, but the advise given on this forum is wrong. I conducted this test fully expecting to confirm the standard advice and give people a jumping off point vs coil-overs, which is still there. However, there was another finding. H&R springs lower the car more than Tanabe springs. I don't care what the manufacturers claim.

The only personal attack is PD attacking my personal work. Next time send me a question in a PM before weighing in to dump on my thread w/o understanding. This is our forum.

McPierson

iTrader: (3)

btw: I've not seem anyone go back to back on Tanabe and H&R springs. So I don't think there's any time and time again. Show me.

timmy0tool

iTrader: (7)

i think it is unclear if you used the stock shock on ALL springs, or did you measure the H&R with the bilsteins? if you kept the shock the same across measurements (stock or bilstein) on different types of springs, then yes the shock would be negligible.

no one is trying to knock your work or personally attack you (from what i've read). it's hard to convey tone of voice over a keyboard so please be careful when reading criticism, which should be expected with an experiment of this nature.

McPierson

iTrader: (3)

Push this back to the top. I gave away both sets of springs and the person is interested in which to put on the car and which to to give to a friend. This thread is perfect for his situation.

Ivan, if the Photobucket images don't show up for you please let me know. I have all the originals. Either my log-in is showing my bucket or they changed the policy to "un-break" the internet.

Zaks

Thanks Matt first off for the springs, second for the testing and definitely for the photos. The photo in your last post... what springs, shocks and shock setting (if applicable/bilstein) is shown there?
I will definitely try to contribute to this thread probably within 2-5 weeks as I gather all suspension components, decide on shocks, etc. However, I'm probably going to be replacing a lot of suspension stuff (maybe everything, like balljoints, bushings, etc.) and of course have new shocks vs whatever is on the car now. As much as I want to put each set of springs on the car without changing anything else, drive around for 1000 miles and report the results, I don't have the time or patience for that. I should be able to at least take some side shots of how it sits now vs when all the new stuff goes on the car. That said, based on everything I've read on here I'm planning to use the Tanabe springs with either KYB or Bilstein shocks. I'm leaning toward bilstein as I've always had BMW and glad to see they're used in the Lexus community a lot as well, but at the same time I do like my Konis more now on my 330 and KYB being softer I may go that route. It will probably be a coinflip in a few days to decide what I order

McPierson

iTrader: (3)

Zaks

400fanboy

If I kept stock springs and swapped in the Bilstein's, you'd argue the ride quality is comparable? My OEM shocks aren't exactly blown, but they're on their way and one of them is leaking oil. Also... aren't the OEM shocks made by Bilstein? Or am I mistaken.

I have a quote for replacing all 4 corners with OEM @ 790 parts, 630 labor. I'm nowhere equipped enough to do the swap on my own hence hiring a shop to do the work. It's on my horizon of something I want to do. I'd like your input for those shocks.

I don't care about handling, I want the best ride quality. AFAIK that means going OEM.

I also could really use some education - what other parts are "while you're in there"? Ball joints? Rack bushings? Are there bushings that connect the shocks to the control arms and the rest of the suspension? I've had several shops visually inspect them and say they're good, but the ride quality and comfort goes out the window long before they're visibly broken.

I've been searching this for a few months and only have a short list of things as I've not found a "mega thread" on refreshing your suspension.