Spring Rates
If you want to get a very rough estimate you can measure the distance from the fender, at the top of the wheel well, to the ground. Then, sit on the fender and remeasure that distance.
From the spring equation F = k x
Where;
F is your weight (lbs)
x is the difference between the two measurements (in)
k is the spring rate or spring constant (lbs / in )
you can divide F by x and find k.
This crude test does not account for the spring being at an angle. If you measure the angle of the spring, relative to vertical, your should multiply your weight (F) by the cosine of the angle.
F cos(angle) = k x
Repeat the test several times with different people sitting on the fender and average the "k" value from all of the test.
If you account for the angle this will likely give you the spring rate within 5 or 10%. It will likely be lower than the actual spring rate due to friction in the shock, lower control arm bushing, etc.
Oopps, I forgot, this test also does not account for the tire compressing, so take your measurements from the rim to the fender, instead of the ground to the fender. The tire will likely have a spring rate of ~ 600 lbs. /in. and you can measure that doing the same test, except measure from the ground to the rim with and without you sitting on it. The tire spring rate will vary with air pressure.
Greenlight
From the spring equation F = k x
Where;
F is your weight (lbs)
x is the difference between the two measurements (in)
k is the spring rate or spring constant (lbs / in )
you can divide F by x and find k.
This crude test does not account for the spring being at an angle. If you measure the angle of the spring, relative to vertical, your should multiply your weight (F) by the cosine of the angle.
F cos(angle) = k x
Repeat the test several times with different people sitting on the fender and average the "k" value from all of the test.
If you account for the angle this will likely give you the spring rate within 5 or 10%. It will likely be lower than the actual spring rate due to friction in the shock, lower control arm bushing, etc.
Oopps, I forgot, this test also does not account for the tire compressing, so take your measurements from the rim to the fender, instead of the ground to the fender. The tire will likely have a spring rate of ~ 600 lbs. /in. and you can measure that doing the same test, except measure from the ground to the rim with and without you sitting on it. The tire spring rate will vary with air pressure.
Greenlight
... sounds good and all but it's hard to isolate one corner of the car so that the swaybar doesn't come into effect. Also, the shock doesn't connect at the ball joint so you'd need to figure the ratio of mechanical advantage (along w/ the trig madness) for this method to yield a meaningful "very rough estimate" spring rate.
Thirdly, the butt dents in the fender tend to bum people out
Thirdly, the butt dents in the fender tend to bum people out
The swaybar only comes into effect when the car starts to roll. The tire that droops helps keep the other tire from compressing and simultaniousely, the tire that compresses keeps the other from drooping.
Originally Posted by RACER' date='Feb 18 2005, 01:02 AM
The swaybar only comes into effect when the car starts to roll. ..................
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Spring rates are list on a thread here:
https://www.s2ki.com/forums/index.php?showt...hl=spring+rates
https://www.s2ki.com/forums/index.php?showt...hl=spring+rates
Originally Posted by RT' date='Feb 18 2005, 07:42 AM
... are you fu<king kidding me? You are kidding right?
Who are you???Why don't you try using the search function on your internet browser.
Your the one joking right?
Funny thing is, I don't think you are









