So I got a deal on springs for the back of the car and now I know why. They are both 400 pounds per inch springs, but they aren't matched. One of the springs has one extra coil. The rate is linear.
What kind of problems will that cause? Should I expect them to behave differently? Coil bind won't be an issue with my travel.
do they both have the same 'resting' height? i.e. while sitting on the table by themselves next to each other is one taller than the other?
rcutclif wrote: do they both have the same 'resting' height? i.e. while sitting on the table by themselves next to each other is one taller than the other?
Same height.
Same wire diameter and spring OD and everything?
Big question: Is it an "active coil" or is it bound at ride height?
Reason I ask: spring rate equation
Cool, then assuming they are both the same rate (I know you said they were) and coil bind is not an issue they should be functionally the same.
I guess one might weight a few grams less than the other? But that should be small potatoes.
I'd run em.
I was worried that while they were advertised as "the same rate", if they have identical wire diameter, outside spring diameter, and are made of the same material but one spring has an extra coil then they wouldn't be the same spring rate (more coils = less spring rate).
Hungary Bill wrote: Same wire diameter and spring OD and everything? Big question: Is it an "active coil" or is it bound at ride height? Reason I ask: spring rate equation
As best I can tell they are the same. Afco 400lb 12" springs. One just has one more coil.
Easier than the equation: Stand on one spring. have someone measure the height. Stand on the other, repeat.
Your weight/inches of deflection (height with no weight minus height with your weight) = lbs/in. Depending on your ability to stand still on top of a spring and your helpers measuring techniques, you should be able to get within 5% or so. At least it will tell you if they really are the same rate or different rates.
If they truly are the same rate with different number of coils, they must be a different material, thinkness, etc. But I think that matters little as long as the intended rate is achieved.
CORRECTION
Two more could on the one spring, but everything else appears to be the same, including wire diameter.
Another idea: contact the seller - maybe he now has a 'matching' set of mismatched springs and would gladly swap one with you.
My worry is:
If you have a spring with 8 active coils (coils not touching anything that actually contribute to absorbing bumps) with a .325 diameter wire, and a spring outside diameter of 2.5" then you'll have a spring rate of 334lbs/in
Same dimensions with 9 active coils knocks the spring rate down to 297lbs/in
You've lost about 40lbs per inch of spring rate (2.5" of compression would yield a 100lb difference from spring to spring).
I don't have the experience to say how much of an effect it will have on the car, but I'd be hesitant (quite possibly due to ignorance).
Can you contact the company?
edited:
Gimp wrote: CORRECTION Two more could on the one spring, but everything else appears to be the same, including wire diameter.
ok with 8 coils on one side, and 10 coils on the other you would now be running
334lbs/in VS 268lbs/in
That's a lot in my book.
Can say 99% they will not be the same rate. If you want to ship'em to me I will test them in my spring rater for $10 a spring. or if you have time and $$ make your own... https://www.facebook.com/media/set/?set=a.487230128050086.1073741834.100002893081629&type=1&l=cb8fab7b4b no FB account needed to see pictures.
44Dwarf wrote: Can say 99% they will not be the same rate. If you want to ship'em to me I will test them in my spring rater for $10 a spring. or if you have time and $$ make your own... https://www.facebook.com/media/set/?set=a.487230128050086.1073741834.100002893081629&type=1&l=cb8fab7b4b no FB account needed to see pictures.
Just dropped you a friend request on the Facebooks. Let's chat.
No way if everything else is the same except for number of winds/coils are they the same rate.
Yeah, mathematically it doesn't work if everything else is the same except for coil count. I wouldn't run them.
Something is off on those springs. I have used both Hypercoil and Summit Racings springs and the springs were identical to each other. No experience with Afco springs, maybe they changed how they are making the springs and you got one old version and one new version.
81cpcamaro wrote: Something is off on those springs. I have used both Hypercoil and Summit Racings springs and the springs were identical to each other. No experience with Afco springs, maybe they changed how they are making the springs and you got one old version and one new version.
I was buying off of the garage sale at Speedway and couldn't confirm part numbers. No big deal, as I found a matching spring and ordered it up. The oddball will likely go to eBay.
If the length and rate are the same and the only difference is the number of coils, the only functional difference is that the one with more coils will have a taller block height - in other words, it can compress less before it becomes completely solid and the spring rate becomes practically infinite.
BTW I got bit hard once by trying to determine a spring's rate from dimensions - I would highly recommend against it.
GameboyRMH wrote: BTW I got bit hard once by trying to determine a spring's rate from dimensions - I would highly recommend against it.
Same here that why I built the tester. Some spring place use a really thick coating other are so thin you'd think it was rattle can over spray.
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