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spring rate testing
locoboy - 24/5/04 at 09:42 AM

Hi,

I think the springs on the coilovers on my F27 are too stiff, there are no markings and i was wondering how i can find out what rating they are so that i can then look at getting some lesser rated ones.

Im in Shropshire so any local advice on where and when would be appreciated.


stephen_gusterson - 24/5/04 at 09:51 AM

I have seen charts - dunno where tho - it may even have been a spreadsheet.

try searching using google, or looking in the files section of TOL.

The spring rate is calc by wire dia, space between coils, spring dia, etc. If you can find the info you should be able to work it out

atb

steve


britishtrident - 24/5/04 at 11:24 AM

there is a formula involving wire thickness and number of working coils it was in the Fred Phun book "How to Make Your Car Handle"


Peteff - 24/5/04 at 12:10 PM

http://www.iroczone.com/calcs/chassis.htm

I haven't tried this so I can't vouch for it. It's the second one down on the page.


RPS - 29/5/04 at 07:03 PM

Just as a matter of interest, I tried out the website on some of my springs.

My Sierra XR4i donor fronts it rated at 129lbs, rears 360 and some s/h coilovers' springs I have, which I had been told were 180lbs, it rated at 250lbs.

RPS


Bob C - 31/5/04 at 04:13 PM

I had a look at this calculator - the formula it uses is:
rate = 1406250 * d*d*d*d / (D*D*D * N)
where rate is in lbs/in, there are N turns, wire diam is d and coil diam is D inches.
It gets the rates of my springs within a couple of percent of the value written on 'em
Cheers
Bob C