Coilover Theory 101: Coil Spring Comparison

[YCW]

Originally Posted by Captain Snooze

Would I be able to tell the difference between the Swifts and the generics? 0.25k doesn't read significant to me.


Why isn't there a rod going through the axis of the spring in the spring tester or a cage around the spring. Do springs never pop out?

The point that hopefully was being made here was that it isn't about the actual difference in this particular test, but more about "consistency". Of course, I would need to run more tests to prove that point. It's coming, I just need to find the spare time to do it.


If the spring rate is consistent between springs (which Swift themselves guarantee), then you don't have to worry about your dampers/springs not being matched. Basically, you have 4 springs on your vehicle and if they are all slightly different rates, that is never a good thing. Also, your dampers are valved to your vehicle setup and spring rate (well, they should be anyway. That is what I'm planning on writing up in the 2nd part of the 101)


Regarding your last question, these linear springs are so short, even at full coil-bind, if the tester decided to let go, the spring wouldn't really fly across the room like a really long oem spring would. It's hard to see in the picture, but the upper and lower mounts on the tester have cups/ridges on them to prevent the spring from flying out.

[ZDan]

Originally Posted by YCW

What determines the rate is the overall mass of steel, not how many coils there are (according to the Swift technician).

That technician has no idea what he's talking about! Spring rate is a function of material modulus of elasticity, wire diameter, coil diameter, and number of turns (i.e., how many coils there are). The "mass of steel" is not directly related to spring stiffness. If you reduce wire diameter, you reduce mass and reduce spring rate. If you increase number of coils, you INcrease mass but still reduce spring rate.

[YCW]

Originally Posted by ZDan

That technician has no idea what he's talking about! Spring rate is a function of material modulus of elasticity, wire diameter, coil diameter, and number of turns (i.e., how many coils there are). The "mass of steel" is not directly related to spring stiffness. If you reduce wire diameter, you reduce mass and reduce spring rate. If you increase number of coils, you INcrease mass but still reduce spring rate.

To be fair, his english wasn't very good, and he did try his best to simplify things for me (I don't speak Japanese btw). I'm sure the technician is well aware of the other parameters/factors.

[ZDan]

Originally Posted by YCW

To be fair, his english wasn't very good, and he did try his best to simplify things for me (I don't speak Japanese btw). I'm sure the technician is well aware of the other parameters/factors.

I appreciate that there must be some misunderstanding. But to be clear, it isn't just that there are "other" parameters involved, the fact is that "mass of steel" tells you *absolutely nothing* about spring rate. If you have two springs and one weighs more than the other, without more info you cannot know which one is stiffer. Heavier could be stiffer, or it could be softer.

[Tcoat]

Originally Posted by ZDan

I appreciate that there must be some misunderstanding. But to be clear, it isn't just that there are "other" parameters involved, the fact is that "mass of steel" tells you *absolutely nothing* about spring rate. If you have two springs and one weighs more than the other, without more info you cannot know which one is stiffer. Heavier could be stiffer, or it could be softer.

Sure but how do you try to shill your product if you have to actually understand all the other factors?

[YCW]

Originally Posted by ZDan

I appreciate that there must be some misunderstanding. But to be clear, it isn't just that there are "other" parameters involved, the fact is that "mass of steel" tells you *absolutely nothing* about spring rate. If you have two springs and one weighs more than the other, without more info you cannot know which one is stiffer. Heavier could be stiffer, or it could be softer.

On it's own, it does not determine the spring rate, you are correct, and other factors must be taken into account. However, where this misunderstanding may have arisen was that the technician was not comparing his spring vs a different brand spring (which is made of a different material). He was trying to explain the differences between spring rates based on their brand spring only, briefly going into detail about mass and coil thickness.


If it was a different brand spring, then obviously these factors change due to the different material.

[YCW]

Originally Posted by Tcoat

Sure but how do you try to shill your product if you have to actually understand all the other factors?

There is not a single person in this world that knows "everything", even those who specialise in a particular field. There is always something more to learn, and in order to advance, you need to learn more. That's a simple fact, whether you are selling lemonade from a little stand, or selling a coilover spring.


But anyway, please, enough of your sarcasm. This thread is not an advertisement, and as I mentioned, any data presented here is just that, data. How you wish to interpret that data is on you, not me.


I can continue to provide data for those who genuinely have interest in this sort of stuff, but if I keep getting these kind of comments from you, then what's the point of me doing this? I'm not getting paid to do this; I'm doing this in my free time because I personally have an interest in this and want to learn more also (as do a lot of people in the community). But I'm not going to continue to do this if all I get is crap from you, plain and simple.

[Tcoat]

Originally Posted by YCW

There is not a single person in this world that knows "everything", even those who specialise in a particular field. There is always something more to learn, and in order to advance, you need to learn more. That's a simple fact, whether you are selling lemonade from a little stand, or selling a coilover spring.


But anyway, please, enough of your sarcasm. This thread is not an advertisement, and as I mentioned, any data presented here is just that, data. How you wish to interpret that data is on you, not me.


I can continue to provide data for those who genuinely have interest in this sort of stuff, but if I keep getting these kind of comments from you, then what's the point of me doing this? I'm not getting paid to do this; I'm doing this in my free time because I personally have an interest in this and want to learn more also (as do a lot of people in the community). But I'm not going to continue to do this if all I get is crap from you, plain and simple.

"The conclusion from all of these tests? Not only are Swift Springs 50% lighter and extremely accurate (you ask for 10K, you get exactly 10K), they also help reduce coil-bind (i.e the coils hitting each other over large bumps). The Taiwan spring? Maybe after 6 months of driving, it will finally be 10K, then 6 months later, 9K!"


"All these tests" consisted of one test upon one spring. Your statement about weight is incorrect since 1.1kg is not "50% lighter" than 1.6kg. It has been pointed out that they are not "exactly" 10K. You even make an unsupported assumption about the other brand. This all reads as a sales pitch and not a very well informed one at that.
If you truly want to learn something then stop answering each reply that tells you how things really are with excuses and rationalization.

[strat61caster]

[YCW]

And I have repeatedly mentioned that I will be adding various other tests. Other brand springs, new and used etc. Or did you not actually read those parts? Were you too fixated on me "advertising"?



My statement about weight is not incorrect, and spring rates when measured in K are in whole numbers. Or is 1-2lbs difference not accurate enough for you? A spring is not static; the compression force constantly varies, hence why I also posted up an example dyno graph.


Unsupported assumption? Where? About the Taiwan spring losing it's spring rate after a few months? That was sarcasm. But again, I mentioned that I will be adding more tests/data to this thread so that you can come to your own conclusion.


I am stating this right now:


1) This is not a sales pitch. No where am I selling anything



2) I will be adding more data, in my free time, to this thread. Just because my initial comparison was Swift vs Taiwan, does not make this an ad for Swift Springs


3) Yes, I wrote "my thoughts/conclusion" in my initial post, but doesn't everyone do that? You do that; you concluded that I am trying to sell something in this thread when I'm not. At least I can "admit" that I made my own conclusion, BUT I also said that whatever data is posted in this thread is up to you to interpret for yourself. I'm not forcing my conclusion on you, and if I'm wrong, I will happily admit it. Will you?


4) No excuses, no rationalisation. I just don't like being accused of doing something that I'm not, especially when all I'm doing is sharing data with the community in my own free time for the community to peruse as they see fit.

[Ultramaroon]

Originally Posted by Spuds

And that's the big IF right? What we really need would be a higher sample size as mentioned before. But that gets expensive pretty quick if you want to be really science-y about it.

Also, what parameters should we really be looking for to determine manufacturing quality other than spring rate?

Well, if referring to the textbook definition of quality, we want to quantify the variance of target requirements. Linearity and usable deflection come to mind. A sample population would have to be destructively tested to find the set deflection.

I will guess that the generic spring will bind before it sets. Looked up the swift. That particular one can be compressed 1.2 inches beyond its maximum rated deflection so I'd be interested in lifespan if I approach that limit in my application.

[strat61caster]

Originally Posted by YCW

1) This is not a sales pitch. No where am I selling anything

http://www.ycwsuspension.com/technology

[YCW]

Originally Posted by strat61caster

http://www.ycwsuspension.com/technology

That's our website, yes. And your point is?


Nowhere in this thread have I mentioned our company nor our website, nor that anything was for sale. All that I have done is post up some test data, and mentioned that I will be posting more data (of other brands, not just Swift).


Just because the initial comparison was Swift vs Taiwan, does not make this an advertisement, regardless of what we have on our website (which I did not even link to nor reference btw)

[stevesnj]

Originally Posted by Ultramaroon

What does 10K mean?