I have a solid cylinder (shaft) that I want to rotate around its axis. The cylinder is supported by two bearings at its ends. No other loads than the weight are applied to the cylinder. My question is; how much torque it needed to rotate the shaft? I don't know how to applied the friction coef. of the GT2 and bearing. 2. how to calculate the torque required to maintain the cylinder rotating at the desired speed once it reaches it. From what I understood, it is dependent on the friction at the bearings only.