Draw a straight line down the shock with a marker. If the spring starts to "unwind" and that line isn't straight anymore, it's bad.
Use a spring rater and check the rate from time to time (every year or two, or if you suspect a problem). Keep this info in a notebook so you can see if a spring is starting to wander from the numbers it had. Some springs right out of the box don't rate like you'd expect them to.
If it's a standard spring (not a barrel), roll it on the bench and see if it wobbles.
Think of it this way , how long does a valve spring last ? How many times a minute does a valve spring compress ? Now compare that to how many times a coilspring on the car compresses . Main thing with most coilsprings is covered above , check for bent , shortened height . I have coilsprings 10 years old I wouldn't have a problem putting in my cars.
Don't worry about the age of the spring, just have them checked. I've had brand new ones that had a pretty significant rate variation that I had to send back. Invest in a spring checker, or find someone with one and have yours checked.
Comparing them to valve springs is apples to oranges. Valve springs are under constant heat and near coil bind every time they move. Suspension springs rarely go into coil bind or anywhere near it and don't have to contend with heat.
A spring rater and notes is the only way to tell. Have kept springs for many years, have returned them straight out of the box. Stay with a good name brand that stands behind their product and check them often. I rated my springs every few nights of racing.
I remember seeing in another thread where a racer used a scale pad in a press to check his springs. Has anyone tried this and compared their results with a true spring checker?
Comparing them to valve springs is apples to oranges. Valve springs are under constant heat and near coil bind every time they move. Suspension springs rarely go into coil bind or anywhere near it and don't have to contend with heat. A spring rater and notes is the only way to tell. Have kept springs for many years, have returned them straight out of the box. Stay with a good name brand that stands behind their product and check them often. I rated my springs every few nights of racing. SPark
My point was , that coil springs don't see near the abuse a valve spring does , so it should last much , much longer . Just trying to get them to think a bit .
I remember seeing in another thread where a racer used a scale pad in a press to check his springs. Has anyone tried this and compared their results with a true spring checker?
Haven't ever compared them , but have used my scale to check flat end springs . Made a set of plates that hold everything in place in the press ,so I don't get killed .
I remember seeing in another thread where a racer used a scale pad in a press to check his springs. Has anyone tried this and compared their results with a true spring checker?
Results will be as good as the scale and measurement technique used.
Springs of any kind don't lose rate because that's built into the mechanics of the spring. They will however lose free height. Free height can be easily compensated for when using a coil overs and adjusters however the amount of travel before coil bind is reduced. The same thing happens to valve springs, Travel is so important in valve spring applications that changing the springs becomes the repair because adjusting is pretty difficult. Sometimes if the conditions are right shimming a valve spring to get some more life out of them is Ok.
In addition to the loss of free height, I've also heard that it isn't the compression aspect of a spring that is lost through time, it is a springs ability to rebound correctly/as it did when new.
Be careful with the black ones. I think we all know the brand. I have had lots of them that weren't right when they were new. I talked to T-Mac this summer and he said the same thing but his are given to him. I went to hypercoil and they are spot on every time.
In addition to the loss of free height, I've also heard that it isn't the compression aspect of a spring that is lost through time, it is a springs ability to rebound correctly/as it did when new.
Can you explain this further please? Im trying to understand the thought process but it eludes me.
i watch free height mainly. springs vary ever so slightly from week to week but when you start noticing changes in free height its time to pitch em.
think about whats happening with your car if that spring starts loosing height halfway through a race. it is going to have dramatic influence on your initial setup.
if you start to notice from week to week your car is just not consistant check the free length of your springs. always take an initial measurement the first time you install a new spring and keep record of the changes you will find some interesting data in that alone.
Hey @Lizardracing, it was Keith Masters that said that about springs losing their rebound ability. Seeing as he has more racecar knowledge in his pinky than I do all together, I believe it. I can't give you a formula or anything to back it up, but just food for thought. Maybe springs are like humans...I'm older now and it takes me a lot longer to get up off the couch? Sorry, that's the best I could come up with.
Lizard, it's similar to shock hysteresis if you're familiar with that. Memory foam is an extreme example of this. The material provides a certain force as you push it in, but as you pull away, it stays compressed, so it's exerting less (or no) force on the "rebound".
I'm not convinced this is necessarily true (significant) with spring steel, and you would need some pretty sophisticated equipment to test it accurately. I attached a rough chart of what a spring exhibiting this behavior would look like on a spring dyno capable of testing it.
I remember seeing in another thread where a racer used a scale pad in a press to check his springs. Has anyone tried this and compared their results with a true spring checker?
We use the scale pad/press method and it was giving us the same readings as a friends rater.
1. Put one scale pad on press, connect it, zero it out, adjust press height to spring.
2. Place spring on scale (if using a spring that is not flat on both ends, you can use a stock lower to hold it level). Put a spring cup in top of coil. Rezero scales
3. Run press down to coil, maintaining zero on scale. Measure free height of coil.
4. Slowly press coil down one inch from what the free height was. Rezero scale. DO NOT RELEASE PRESS!
5. Press coil down one more inch from previous height. The reading on your scale is your coil rating.
Senior Member
Coil Springs?
Originally Posted by LM14
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