What Spring Rate Do I Need?

What Spring Rate Do I Need?

fabtechrockFabtech is an award winning suspension lift kit manufacturer that produces a number of different coil spring based systems.
Off-roading is exciting, a little dangerous, and fun as hell. If you’re doing some serious mudding or rock crawling, it’s important that you have the proper coil suspension and spring rate. Often, OEMs (Original Equipment Manufacturers) will fit a vehicle with a spring rate that is primarily designed for ride comfort and handling a variety of terrains. But, what if you are seriously into mudding? Rock crawling? Then, you will need an aftermarket suspension system that has a spring rate that will compliment your ventures.

Coil Dimensions and How They Affect the Spring Rate

The spring rate of a coil spring suspension system is always expressed in pounds per inch (lb/in) of spring travel. The pounds per inch are determined from three factors:
  1. The coil wire diameter
  2. The number of active coils. These do not include the flattened coils at the ends.
  3. The mean diameter of springs. This is half way between the inside and outside diameter.
If you wanted to calculate your spring rate, you would plug those three factors into this equation:

Spring Rate = (1406250 x W x W x W x W) / (N x D x D x D)

W= coil wire diameter in inches
N= Number of active coils. The flattened coils at the ends are not considered active.
D= Mean diameter of springs. This is half way between the inside and outside diameter.

Of course if math isn’t your thing, you could always go onto the internet and use one of the easy to find spring rate calculators. There are a few basic principles to keep in mind as you think about spring rates.
coilspringsMake sure you have the proper spring rate for your truck!
  • The spring rate increases as the wire diameter increases.
  • The coil rate decreases as the mean increases.
  • The spring rate decreases as the number of active coils increases.
  • Fewer active coils yield a stiffer spring rate
What Spring Rate Do I Need?

Well, there are a number of factors to keep in mind, like vehicle type and lift height. But, here are some basic guidelines. For those that will be doing some serious rock crawling or mudding, you’re going to want a softer spring rate for slow-speed articulation. On the contrary, a high speed off-roader may want a stiffer spring rate to handle the bouncing that will occur.

Currently, the award winning Fabtech suspension lift kits are one of the best coil suspension systems at 4 Wheel Online. They have a number of different coil spring systems that are aimed at satisfying all of your needs and giving different variations of support. All of Fabtech’s products are easy to install and come with a manufacturer warranty. The bottom line: they are too good not to check out.

By: Tim Snyder
Posted on August 26th, 2013
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