Help with spring rates
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From: Palo Alto
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Help with spring rates
Hey all,
someone asked me a question about my springs and I can't really answer it since I'm not that knowledgable with suspension:
"Hey Ambert,
Can you do one thing for me? Can you translate the spring rate
to lbs/in pls? I'm coming up with something like 168lbs/in which makes
them a lil too soft for me, just a few lbs over stock. I hope I'm doing
it wrong. How stiff were they for youbtw? Thanks.
Dinh"
These are Tanabe Sustec GF210 (babysmurf you can correct me if I'm wrong)
Thanks!
Ambert
someone asked me a question about my springs and I can't really answer it since I'm not that knowledgable with suspension:
"Hey Ambert,
Can you do one thing for me? Can you translate the spring rate
to lbs/in pls? I'm coming up with something like 168lbs/in which makes
them a lil too soft for me, just a few lbs over stock. I hope I'm doing
it wrong. How stiff were they for youbtw? Thanks.
Dinh"
These are Tanabe Sustec GF210 (babysmurf you can correct me if I'm wrong)
Thanks!
Ambert
im stooped
btw can someone explain to me what rates for coil overs mean?
as in 5kg front and 7kg (or is it just k) or what? i can't remember right now, hopefully somone knows what im talkin about
btw can someone explain to me what rates for coil overs mean?
as in 5kg front and 7kg (or is it just k) or what? i can't remember right now, hopefully somone knows what im talkin about
Registered User
Joined: Jul 2003
Posts: 221
From: Bay Area, CA
Car Info: '05 LGT
I'm not sure exactly what the question is but here's this site with the stock spring rates among others.
http://www.ravensblade-impreza.com/t...ng/spring.html
The Tanabe Sustec GF210 are supposed to be 20-30% higher than stock according to this.
http://www.hpautoworks.com/tasugflosp.html
http://www.ravensblade-impreza.com/t...ng/spring.html
The Tanabe Sustec GF210 are supposed to be 20-30% higher than stock according to this.
http://www.hpautoworks.com/tasugflosp.html
Originally posted by Daredevil
im stooped
btw can someone explain to me what rates for coil overs mean?
as in 5kg front and 7kg (or is it just k) or what? i can't remember right now, hopefully somone knows what im talkin about
im stooped
btw can someone explain to me what rates for coil overs mean?
as in 5kg front and 7kg (or is it just k) or what? i can't remember right now, hopefully somone knows what im talkin about
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Posts: n/a
On US rated springs it takes however much wieght ( or simulated wieght ) to compress the spring 1 inch.
IE
150lb/in springs take 150lbs to compress 1 inch, and another 150lbs on top of that to do another etc etc.
the spring rates on the metric work the same, some are rated per mm or cm though, if you do the conversions it should work out the same.
this will vary on progressive versus linear rate springs though, an eibach ERS spring ( race spring, 2.5" ID typically ) is linear, most factory replacement type springs are a progressive rate, so the inital rate is going to be much lighter which could be what your friend is comming up with, the 170lb/in could be the inital rate but after 1-2 inches the rate could go up to 300 lb/in , it all depends on the manufacter specs.
here is some useful info I just found as well
In order to find the pounds of a kilogram spring you need to do the following:
8kg-mm >> 8 (kilograms) x 2.22 (pounds in a kilogram) = 17.76 (pounds in a millimeter)
17.76 (lbs in a mm) x 25.4 (mm in an inch) = 451.104 (lbs in an inch)
So this would mean that an 8kg-mm spring translates to a 451 lbs-in spring
the specs on the Tanabe GF210 are as follows
front is rated at 4.3kg/mm and rears at 4.0kg/mm or
Front at 242 lbs/in and rear at 225 lbs/in
hope this helps
Nate
S-Squared
IE
150lb/in springs take 150lbs to compress 1 inch, and another 150lbs on top of that to do another etc etc.
the spring rates on the metric work the same, some are rated per mm or cm though, if you do the conversions it should work out the same.
this will vary on progressive versus linear rate springs though, an eibach ERS spring ( race spring, 2.5" ID typically ) is linear, most factory replacement type springs are a progressive rate, so the inital rate is going to be much lighter which could be what your friend is comming up with, the 170lb/in could be the inital rate but after 1-2 inches the rate could go up to 300 lb/in , it all depends on the manufacter specs.
here is some useful info I just found as well
In order to find the pounds of a kilogram spring you need to do the following:
8kg-mm >> 8 (kilograms) x 2.22 (pounds in a kilogram) = 17.76 (pounds in a millimeter)
17.76 (lbs in a mm) x 25.4 (mm in an inch) = 451.104 (lbs in an inch)
So this would mean that an 8kg-mm spring translates to a 451 lbs-in spring
the specs on the Tanabe GF210 are as follows
front is rated at 4.3kg/mm and rears at 4.0kg/mm or
Front at 242 lbs/in and rear at 225 lbs/in
hope this helps
Nate
S-Squared
Last edited by S-Squared; Dec 29, 2003 at 06:00 PM.
Guest
Posts: n/a
Originally posted by Daredevil
im stooped
btw can someone explain to me what rates for coil overs mean?
as in 5kg front and 7kg (or is it just k) or what? i can't remember right now, hopefully somone knows what im talkin about
im stooped
btw can someone explain to me what rates for coil overs mean?
as in 5kg front and 7kg (or is it just k) or what? i can't remember right now, hopefully somone knows what im talkin about
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From: GST Motorsports - Rally Division
Car Info: dangerous with a wrench
If they are the same perrin springs as I've seen in the past, they are a progressive rate spring, but I haven't measured them to know what the rate curve is like.
Registered User
Joined: Jan 2004
Posts: 80
Spring are rated in units of force per unit of displacement.
The metric unit of force is the Newton, so spring rates are rated in Newtons per millimeter (N/mm). The gram is a unit of mass. In english units it is pound force per inch (lbf/in).
The metric unit of force is the Newton, so spring rates are rated in Newtons per millimeter (N/mm). The gram is a unit of mass. In english units it is pound force per inch (lbf/in).
Registered User
Joined: Sep 2004
Posts: 49
Correction 1 inch is .04 mm so to convert Kg/mm to lb/in you multiply by 2.2lbs then devide by .04. or the quick way is to multiply by 55.5. Those 8Kg springs would actually be 8x55.5=444lb/in.
Another is converting N/mm to lb/in. 1N is .225lb so you multiply by .225 then devide by .04 again the quick way is just to multiply by 5.625.
BTW Some places that use the metric system also rate horsepower in PS. -PSx.986=HP it's still based on how much weight a donkey can haul up a mine shaft though, i think.
Another is converting N/mm to lb/in. 1N is .225lb so you multiply by .225 then devide by .04 again the quick way is just to multiply by 5.625.
BTW Some places that use the metric system also rate horsepower in PS. -PSx.986=HP it's still based on how much weight a donkey can haul up a mine shaft though, i think.
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