Springs shape - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

gpvecchi · 11-04-2020, 04:46 PM

Sorry guys, if you take two springs, with same wire diameter, same lenght, etc, but with different number of coils, which one will be the stiffest?
The one with more coils or the one with less?

soundman98 · 11-04-2020, 08:45 PM

what is the point of reference here?

have you ever stretched pen springs, to shoot the cartridges into the ceiling tiles in class, or annoy the cute blonde in the front row? similar concept to your question.

the number of coils will have very little difference in stiffness, but an increasing amount of coils will drastically reduce the overall spring height, reducing the available shock stroke length.

bcj · 11-04-2020, 09:07 PM

A straight line from point a to point b would resist deformation the most.
You'll have to divulge more succinct parameters to proceed from there.

There's barrel shaped springs so the coils can get out of each others way.
More coils will be heavier and hysteresis will make them react slower, and, and ...

... you can move the world with a lever long enough. I haven't tried this yet.

soundman98 · 11-04-2020, 09:40 PM

Quote:

Originally Posted by bcj

... you can move the world with a lever long enough. I haven't tried this yet.

the real problem there is what one would use for a fulcrum.

gen3v8 · 11-05-2020, 03:00 AM

The longer the wire? the softer the spring. So more coils would mean longer therefore softer

churchx · 11-05-2020, 03:47 AM

There are large count of parameters at play but just diameter/coil count/thickness of coil, shape (eg. as with progressive coils), and most importantly - material and manufacturing QA.
By just few of them known i see no way to tell except testing/measuring by yourself.
Any practical case you may need answers to this? Have pile of springs with no specs from manufacturer? Imho known quality spring manufacturers should provide specs for their products w/o need to measure yourself or playing guesswork with just few variables known. Not sure i'd wish to use springs of unknown quality and possible variance in spring rates between them due worse QA in manufacturing.

ZDan · 11-05-2020, 04:10 AM

Doubling the number of coils gives half the spring rate.
Halving number of coils doubles spring rate.

K = (G * d^4) / (8 * N * D^3)

K is stiffness
G is material shear modulus
d is wire diameter
N is number of active turns or coils
D is mean spring diameter

gpvecchi · 11-05-2020, 08:02 AM

So, more coils, more soft. This is what I was looking to, thanks!

Tcoat · 11-05-2020, 10:30 AM

Quote:

Originally Posted by ZDan

Doubling the number of coils gives half the spring rate.
Halving number of coils doubles spring rate.

K = (G * d^4) / (8 * N * D^3)

K is stiffness
G is material shear modulus
d is wire diameter
N is number of active turns or coils
D is mean spring diameter

Quote:

Originally Posted by gpvecchi

So, more coils, more soft. This is what I was looking to, thanks!

No. It is not that simple. As Dan said the number of coils is only one part of the equation. You can not simply ignore all the other required data and go by number of coils.

norcalpb · 11-05-2020, 12:59 PM

Quote:

Originally Posted by Tcoat

No. It is not that simple. As Dan said the number of coils is only one part of the equation. You can not simply ignore all the other required data and go by number of coils.

Yup, my soft STi springs have fewer coils than my stiff RCE springs.

BarryOtt · 11-05-2020, 04:34 PM

Quote:

Originally Posted by Tcoat

No. It is not that simple. As Dan said the number of coils is only one part of the equation. You can not simply ignore all the other required data and go by number of coils.

Perhaps you missed the first post:

Quote:

Originally Posted by gpvecchi

Sorry guys, if you take two springs, with same wire diameter, same lenght, etc, but with different number of coils, which one will be the stiffest?
The one with more coils or the one with less?

Based on his first post, this is correct:

Quote:

Originally Posted by gpvecchi

So, more coils, more soft. This is what I was looking to, thanks!

gpvecchi · 11-05-2020, 04:45 PM

Yes guys, I just wanted to know how this parameter influences the stifness, I know there are a lot of other ones to consider...

pallen · 11-05-2020, 04:50 PM

We can go deeper

Tcoat · 11-05-2020, 06:22 PM

Quote:

Originally Posted by BarryOtt

Perhaps you missed the first post:

Based on his first post, this is correct:

Perhaps you missed the fact that there are many materials that springs are made of and that is a major part of the equation.
You can not just take two of the parts of the equation and get an answer. Not even a ball park one.
But go ahead just make shit up and run with it since it makes no difference to me.

11-04-2020, 04:46 PM	#1
gpvecchi Senior Member Join Date: Mar 2018 Drives: Toyota 86 GT Limited PP (Model G) Location: Italy Posts: 1,018 Thanks: 406 Thanked 335 Times in 187 Posts Mentioned: 14 Post(s) Tagged: 0 Thread(s)	Springs shape Sorry guys, if you take two springs, with same wire diameter, same lenght, etc, but with different number of coils, which one will be the stiffest? The one with more coils or the one with less?

11-04-2020, 08:45 PM	#2
soundman98 ProCrastinationConsultant Join Date: Sep 2013 Drives: '14 Ranger, '18 Tacoma 4Dr LB Location: chicago-ish Posts: 11,330 Thanks: 35,240 Thanked 13,673 Times in 6,781 Posts Mentioned: 98 Post(s) Tagged: 0 Thread(s)	what is the point of reference here? have you ever stretched pen springs, to shoot the cartridges into the ceiling tiles in class, or annoy the cute blonde in the front row? similar concept to your question. the number of coils will have very little difference in stiffness, but an increasing amount of coils will drastically reduce the overall spring height, reducing the available shock stroke length. __________________ "The time you enjoy wasting is not wasted time"

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churchx Senior Member Join Date: Mar 2015 Drives: 2014 GT86 Location: Latvia, Riga Posts: 4,333 Thanks: 696 Thanked 2,085 Times in 1,436 Posts Mentioned: 53 Post(s) Tagged: 1 Thread(s)	There are large count of parameters at play but just diameter/coil count/thickness of coil, shape (eg. as with progressive coils), and most importantly - material and manufacturing QA. By just few of them known i see no way to tell except testing/measuring by yourself. Any practical case you may need answers to this? Have pile of springs with no specs from manufacturer? Imho known quality spring manufacturers should provide specs for their products w/o need to measure yourself or playing guesswork with just few variables known. Not sure i'd wish to use springs of unknown quality and possible variance in spring rates between them due worse QA in manufacturing.

11-05-2020, 04:10 AM	#7
ZDan Senior Member Join Date: May 2011 Drives: '23 BRZ Location: Providence, RI Posts: 4,584 Thanks: 1,377 Thanked 3,891 Times in 2,032 Posts Mentioned: 85 Post(s) Tagged: 0 Thread(s)	Doubling the number of coils gives half the spring rate. Halving number of coils doubles spring rate. K = (G * d^4) / (8 * N * D^3) K is stiffness G is material shear modulus d is wire diameter N is number of active turns or coils D is mean spring diameter

11-05-2020, 08:02 AM	#8
gpvecchi Senior Member Join Date: Mar 2018 Drives: Toyota 86 GT Limited PP (Model G) Location: Italy Posts: 1,018 Thanks: 406 Thanked 335 Times in 187 Posts Mentioned: 14 Post(s) Tagged: 0 Thread(s)	So, more coils, more soft. This is what I was looking to, thanks!

11-05-2020, 04:45 PM	#12
gpvecchi Senior Member Join Date: Mar 2018 Drives: Toyota 86 GT Limited PP (Model G) Location: Italy Posts: 1,018 Thanks: 406 Thanked 335 Times in 187 Posts Mentioned: 14 Post(s) Tagged: 0 Thread(s)	Yes guys, I just wanted to know how this parameter influences the stifness, I know there are a lot of other ones to consider...

11-05-2020, 04:50 PM	#13
pallen Senior Member Join Date: Jun 2020 Drives: 2017 Toyota 86 Location: Fort Worth, TX Posts: 261 Thanks: 200 Thanked 184 Times in 110 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	We can go deeper

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