Spring Rates

[NCSU_racer]

Trying to figure out what springs are on my car and they aren't marked. Does color have anything to do with what spring rate it is?

[IraceLegends77]

Color is more of a make not a rate. You will need to find someone with a spring dyno. But before you do that look at both ends of the spring (in good light) and make sure nothing is stamped on them or etched

[NCSU_racer]

10-4 thanks.

[Earnst85]

Spring rate is the weight resistance for 1" of movement, therefore,
I rate my springs every-so-often using my scales and a shop press like this:

- Put one scale pad on the press with the spring and set the press that it is barely pressing the spring (holding it in place).

- Zero the scales.

- Using the press, press the spring to 1" & 2". Record the weight at each distance.

- Divide your 2" weight by 2 and then average your 1" weight & 2" divided weight. This will be your spring rate.

You can increase the accuracy by measuring at more lengths. Just be careful of the spring jumping out of the press.

Example:  weight @ 1" = 160 LBS, weight @ 2"= 328 LBS ===>   [160+ (328/2)] / 2 = 162 LB spring

[legends13]

The above method will work, but i highly advise against it, unless you have a fixture made up to do so. A few issues:

Using the press alone is not safe. The spring could pop out and do serious damage to anyone near-by. I have built a fixture to do this, and it basically makes it so the spring cant pop out.

Second, measuring needs to be precise. even a few thousandths of an inch can affect the rate. If you are looking for accurate rating, again, build a fixture using a dial indicator.

Third, it is not simply measure an inch and that is the rate. You need to compress the spring about an inch, then zero the scale, and compress another inch. This rating is much more accurate...

If interested, PM me your email address and I will send some pictures of my "spring rater"

[knoxracing]

I agree Brad. The new raters are digital, my rater works from dial indicators and is designed to do coil springs. I had a customer bring me a box of springs, they were all marked. I put them through my spring rater and they were all off, I ask him where he cam up with the numbers. He tried the exact same method at home, he did not know we had a rate tester until someone told him I had one. This also has to do with why we run 8" springs (hint).

[amp racing]

ok dennis,  i'll bite... is there a difference in the two sprigs 8 inch and 10 inch?   
joe

[Grape Competition Develop]

according to my spring checker software from roehrig, the only difference is weight....  I'm sure some others will try to tell you one reacts quicker than another....... yawn

[justfreaky]

Not that an 8" spring reacts any quicker than a 10" spring; It has to do with spring travel.

Steve

[knoxracing]

These springs are only 1.87 i.d., the deflection difference between the 8 and 10 is enough for us to switch to the 8.