I got a new benchtop spring tester, and decided to do some prep measuring on the PAC 1518 springs I have, so the first thing I wanted to measure was coil bind.

Before I began, I figured I'd just crank them down till I can't crank anymore and coil bind would be pretty obvious to see. Problem with this is I could have kept cranking past the 600-lb rating on the gauge.

Then I decided to go for "visual" coil bind, so I cranked them down until it visually looked like the coils were coming into contact. I tried getting feeler gauges inside, used a flashlight and magnifying glass to try to get to the exact point where the springs would touch, because I figured if the coils were touching, that was as close as I would want them anyways.

I think the differences between my two methods was 0.035" in some cases. And from my "visual" coil bind measurements, I'm probably going to shim the springs to .050-.060" from "visual" coilbind of 1.080".

Does this seem about right? For those of you who have measured coilbind before how far are you compressing the springs?

 

I always compressed the springs until I could feel a noticeable spike in the amount of effort to compress the spring any more, and that's where I stopped. You should be able to feel it when you hit this "wall". I wouldn't keep cranking on the wheel as hard as I could, but it was a little further than "visual" coildbind.

If you're not sure, it's probably better to err on the larger coilbind measurement. The consequences are a lot worse if you're too tight versus too loose.

 

You can compare PAC's coil-bind rating (1.080") to what you're seeing and you start to get a feel for it. You will also see the bottom piece of the scale start to move downward if you over-crank it, and that is obviously too far.

 

Not sure what tool you are measuring with but some testers don't like going to far in load. Also, why not just use the value provided by PAC? These are formed springs that are made within tolerances, they should be darn close to the specification.

 

The LSM 600lb tester, it's a horizontal mount one. And the box says 1.140" but the website says 1.080". I may have gotten an older batch, which annoys me somewhat, but that's why I decided to test...that, and I'm over precise on a lot of things I build.

More than likely I will set everything up with a 1.080 theoretical coil bind and shim accordingly.

 

Yep and just do the math and you'll be damn close...

 

I took my springs to a local engine builder he put them on a machine that measures the spring forces from open to coil bind and provides a printout. Worked out very well for figuring shims needs and open closed figures. He charged me like 25 bucks.