Hello everybody! Bill here from QA1. Tait here. Today we're going to talk to you
about springs different kinds of springs and what the spring rate actually means.
There's a bunch of different kinds of springs to be aware of. Mostly what we
deal with in the coil-over world and in the performance car and truck market is
coil springs right? You can put them on your shock and have a coil-over you can keep them
away from the shock and then it's not technically a coil-over but it still has a coil spring right?
Coil simply means it's coiled but there's also different kinds of springs there's leaf springs.
This is a leaf spring off of a Corvette. Common to find them under the back ends of pickup trucks
old cars front ends old pickup trucks and old cars. Coil springs started coming around mostly
in the 50s? Say in the 50s yeah. Around the 50s and that's primarily what you still see today.
There's torsion springs which are like a long bar that gets twisted. A sway bar is an example of a
torsion spring. All of them are doing the same thing. They're just resisting basically if you
compress this spring if I push this way on the spring the spring's pushing back that way right.
If I push down on these two points on this spring then the center's pushing up right. So it's
they're all doing the same thing they're just resisting they're pushing back when you push
on them. Pushing back against the force that's there. Yep now that you know what
springs are in the different kinds of them you can get a little bit more technical.
The way springs are generally looked at or talked about is in spring rate. So what is spring rate?
It's simply a measurement of how much force it takes to compress a spring a given amount. Here
in America we say pounds per inch in Europe and Asia they use kilograms per millimeter.
They're giving you the same information just in different units. Here what we use pounds per inch.
This is a 12 pound per inch spring which means that it takes 12 pounds to compress the spring
one inch takes another 12 pounds to compress the spring a second inch so on and so forth. So one
thing you can do with springs if you know what your spring rate is and we do this all the time
is if you know what the spring rate is you can measure how long it is when this car is on them
and then you can use that measurement. So say this is a 10 inch spring and it's compressing down to
7 inches it tells us that we're compressing 3 inches from the free length right. If we know the
free length and how far it's compressing and the spring rate we can tell you how much force is on
that spring. So you can actually use a spring as like a scale. Right you can get the sprung weight
from a vehicle less the unsprung weight which is a pretty nice way to figure out where you need to be
for spring rate or where you're at. Yep they're pretty handy. So we can if we can tell how much
force is on a spring okay that's great. But how do we know if that's too much too little
what are we looking for? A lot of what you're going to experience in driving is going to tell
you about where you're at for spring rate if you notice you have a lot of body roll a lot of nose
dive under braking that may well be a sign that you are under sprung have too soft of a spring.
If you are feeling everything on the road and it's really harsh you're probably over sprung
these are things that can be easily corrected again by taking stock of the compressed length
of the spring and putting the math to it and correcting that we can usually get a lot closer.
Well I hope that demystified springs a little bit for you if you have any questions at all
feel free to give us a call on the tech line send us an email. And if you do want to look into any
of this further we have lots of information in our tech articles at our website QA1.net.