Critical Speed & Your Driveshaft
Critical speed is the rpm at which the driveshaft becomes unstable. All driveshafts have a critical speed; it depends on the length and diameter. Securing a more favorable critical speed can be achieved by changing any of several driveshaft variables. They include the length, tube diameter, materials used to build and the RPM of the driveshaft.
For more information on how to calculate the critical speed for your driveshaft please visit https://spicerparts.com/calculators/critical-speed-rpm-calculator