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Author Topic:   spring rates for coilovers at angles
1Pro4
Member
posted February 21, 2001 08:21 AM
iv seen the chart for spring rate % at angles the way i under stand it is the spring rateXthe proper % per angle according to the chart is this correct?,,,,,also,,guess its easy to tell im new at what i consider a "real" race chassis,,,,,i have heard that mounting a coilover on a swing arm produces at spring rate at 50# less than the actuall springs rating is this true? and if it is true,,,,is the angle reduction proportional to the lost rate for a swing arm mounted coilover? that make any sense??? should deduct 50# from the rate and then use the angle chart?


jammin
Administrator
posted February 21, 2001 05:48 PM
To get the spring rate for the swing arm......just measure the length of the arm from the chassis mount to the rear mount(a).....then measure the length from the the chassis to the spring(on the same arm)(b). Then divide (b) by (a) and then multiply it times your spring rate, this will give you the actual rate of the spring that is on the tire.

If you would like, I might be able to build a little program to do it for you on your puter if you think it would be beneficial.

jammin


1Pro4
Member
posted February 22, 2001 07:44 AM
great and u shoulda figured that out on my own,,,,,but know my question is....from what i understand by that coilover chart is,,mounting the coilover at and angle changes the rate of the spring,,,sorta,,anyway,,,after i have used the formula u have given me here jammin,,do i take this swingarms mounted rate we have from your formula and use the coilover angle chart now? thats easy enough to remember ,,a program to figure it wouldnt be ness. but if you have one that would show me the center of gravity of my car ,,using tape measure info from the physical car and percentages from computer scales id be a happy camper! =) by the way this is the best race forum iv found actually learn something here no bs!


1Pro4
Member
posted February 22, 2001 07:51 AM
also i wonder why we mount our coilovers at angle? iv been told over and over they are best mounted straight up and down. but it seems no one does it, the chassis i have,mounted the eliminaters at an agle,,,im wondering if i should put in new top mount to run em straight up?


jammin
Administrator
posted February 22, 2001 10:57 AM
The reason, they are best to run straight up and down is that you do not have to do the math to figure what the rates are when they lean. If you take the formula I gave you and then multiply the answer times the angle that they are on the scale above, then you will get the true rate of your spring. Then you will have to change your spring to the get the correct rate that you want. The more the angle...less spring rate basically..

Pro Shocks has a neat little calculator at http://www.proshocks.com/calcs/anglefirst.html that you should check out.

jammin


1Pro4
Member
posted February 22, 2001 10:03 PM
so u feel there is no advantage to running the springs straight up and down? there is no physical diffrence? exept of coarse having to do the math? it seems to me at the least that shocks would try to bind at least alittle,whether it is enough to matter i dont know. the math is the only diff? is the a car weight chart to put u in the ball park on all four corners for spring and shocks? thanx for the help jammin


jammin
Administrator
posted February 22, 2001 10:44 PM
as long as there is no bind on the shock or eliminator ends, it wont bind....but you can overboard on the angle...dont get me wrong. It does make a difference... I wouldnt go over a 30 degree angle unless I had to...you dont want to go way out in left field.



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