A driveshaft is just like any other rotating assembly with a center of gravity. The driveshaft’s center of gravity is the point about which the driveshaft’s weight is equally distributed.
The driveshaft rotates around a center of axis. When the center of gravity is not on the rotational center of axis, the driveshaft is unbalanced.
A dynamic unbalance is when the center of gravity line of axis is not parallel with the shaft line of rotational axis.
An unbalanced shaft wants to rotate around its center of gravity axis, but is held into the shaft line of rotational axis with pinion bearings and transmission tail shaft bushing. The bearings restrict movement, and the centrifugal force of unbalance causes vibrations. The vibrations can lead to premature u-joint, bearing and bushing failure. The vibrations can also be annoying as hell.
The solution to driveshaft dynamic unbalance is to move the center of gravity line of axis into the shaft line of axis. This is done by measuring the unbalance, and using additional weight to move the center of gravity to the line of rotational axis.
OC Driveshaft uses the Hines DL-500 driveline balancer for measuring and correcting driveshaft unbalance. Driveshafts are precision balanced according to the ISO 1940/1 standard specification of grade 6.3 or better.