{"id":2802,"date":"2003-07-29T22:53:00","date_gmt":"2003-07-30T05:53:00","guid":{"rendered":"http:\/\/roadraceengineering.com\/blog\/?p=2802"},"modified":"2011-12-29T23:04:01","modified_gmt":"2011-12-30T07:04:01","slug":"how-to-rate-coil-springs-without-a-rater","status":"publish","type":"post","link":"http:\/\/roadraceengineering.com\/blog\/2003\/07\/29\/how-to-rate-coil-springs-without-a-rater\/","title":{"rendered":"How to Rate Coil Springs Without a Spring Rater Tool"},"content":{"rendered":"
<\/div>

Mathematical Spring Rating Formula<\/p>\n

Not many people have access to a spring rating tool. You can come a lot closer than you would think just using some dial calipers and a measuring tape to measure the spring rate of your springs. Here is how to do it:<\/p>\n

SPRING RATE = GD4\/8NM3<\/p>\n

G\u00a0\u00a0= Torsional Modulus for Steel\u00a0\u00a0\u00a0\u00a0\u00a011.25 x 106
\nD =\u00a0Wire Diameter in Inches
\nN =\u00a0Number of Active Coils
\nM\u00a0=\u00a0Mean Coil Diameter in Inches.\u00a0Mean Diameter Is:<\/p>\n

If using I.D. = 1 Wire plus Inside Diameter
\nIf using O.D. = 1 Wire minus Outside Diameter<\/p><\/blockquote>\n

8\u00a0\u00a0\u00a0= A Constant for all Coil Springs<\/p>\n

The “G” Factor is always the same for all coil springs made from
\nsteel\u00a0\u00a0(11.25 x 106\u00a0can also be written as 11,250,000).<\/p>\n

EXAMPLE:\u00a010 active Coils and a mean coil diameter\u00a0of 5.00 inches and a wire size of .625<\/p>\n

11,250,000 x .625 x .625 x .625 x .625\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0=\u00a0\u00a0\u00a0\u00a0171,661,370
\n8\u00a0x\u00a010\u00a0x\u00a05.0\u00a0x\u00a05.0\u00a0x\u00a05.0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 10,000<\/p>\n

(Constant) x (Active\u00a0Coils)\u00a0 x \u00a0(Mean Dia.) x (Mean Dia.) x (Mean Dia.)<\/p>\n

Spring Rate\u00a0\u00a0\u00a0\u00a0=\u00a0\u00a0171,661,370 \/ 10,000<\/p>\n

Spring Rate\u00a0\u00a0\u00a0\u00a0=\u00a0\u00a0171.66 lbs.\/per inch<\/p>\n

HOW TO DETERMINE ACTIVE COILS OF A COIL SPRING:<\/p>\n

Count total number of coils, subtract a coil for each coil that touches, these are dead coils. Ground flat ends are a dead coil.\u00a0\u00a0Start count with cut-off end facing you directly above would be one and so on. Not all coil rings are even coiled. You can have .125, .25, .5 or .75 of a coil (Example 10.25 Coils).<\/p>\n

 <\/p>\n

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Mathematical Spring Rating Formula Not many people have access to a spring rating tool. You can come a lot closer than you would think just using some dial calipers and a measuring tape to measure the spring rate of your springs. Here is how to do it: SPRING RATE = GD4\/8NM3 G\u00a0\u00a0= Torsional Modulus for […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[55],"_links":{"self":[{"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/posts\/2802"}],"collection":[{"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/comments?post=2802"}],"version-history":[{"count":5,"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/posts\/2802\/revisions"}],"predecessor-version":[{"id":2807,"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/posts\/2802\/revisions\/2807"}],"wp:attachment":[{"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/media?parent=2802"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/categories?post=2802"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/roadraceengineering.com\/blog\/wp-json\/wp\/v2\/tags?post=2802"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}