Unequal Pitch Shock Springs


The stock spring on my 06 YZ450 is the equal pitch spring. But they offer an unequal pitch spring that is softer at the beginning of the stroke and hardder at the end. I believe this is also called a variable rate spring.

My first reaction is this sounds like a good idea. Are these springs popular/better? Is it better for enduro riding than MX since it soft at the beginning?



San Antonio, TX

These springs work much differently in practice than a straight rate does, and they aren't for everyone

Imagine, in place of your single rate 10" spring, you have a spring with an 7" stiff section and a 3" soft section at one end. The stiff section is 100 inch pounds, and the soft section is 50. Many believe that the soft section will completely compress before the stiff section moves, but that's not correct. If you apply 100 pounds to the spring, the 50 pound section will compress 2 inches, true. But it sits on the 100 pound section, doesn't it? That means that the 100 pound section will compress an inch, too. That means that the effective rate of the spring is 33 inch pounds until the 50 pound section binds up, at which point it becomes a 100 pound spring. In dual rate springs like the example, this rate spike is sudden. In a progressively wound, or "unequal" rate spring, the spring rate ramps up more progressively as the tighter wound coils bind against each other.

As it is already, the linkage produces this effect with a straight rate spring, because the shock travels farther per inch of wheel axle travel in the last inch than in the first, so having the spring do it as well may not be what you're looking for.

Most people don't use them, but they do serve a purpose.

Thanks for the great reply!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now