Spring Rate Calculator: operating questions
Does the calculated rate prove the spring is safe?
No. Rate is a stiffness result. Corrected wire stress, fatigue, solid height, buckling, surge, end condition, tolerances and relaxation remain separate design checks.
Which coil diameter belongs in the equation?
Use mean coil diameter, measured between wire centrelines. Substituting outside diameter makes the spring appear softer than the same physical spring evaluated correctly.
Why is wire diameter so influential?
Rate varies with the fourth power of wire diameter. Small wire-size or manufacturing deviations can therefore produce a meaningful rate change.
| Parameter | Unit | Example |
|---|---|---|
| Wire diameter | mm | 5 |
| Mean coil diameter | mm | 35 |
| Active coils | count | 8 |
| Shear modulus | GPa | 79 |