I want to use a DC 12/24V motor to rotate an assembly of glass tubes(image attached) through a hollow shaft of 25mm OD and 22mm ID, the shaft is supported on bearings on both the sides(assume minimum friction), two 3mm thick circular plates hold the four tubes together at both the end. The shaft is attached to the center of the disk. Data- Glass tube- 58mm OD,45mm ID , 1.8m long Disk- 180 mm OD, 3mm thick attachd at 25mm from both the edges of the glass tube.

Even a general procedure/idea of calculating torque requirement is appreciated  

I want to use a DC 12/24V motor to rotate an assembly of glass tubes(image attached) through a hollow shaft of 25mm OD and 22mm ID, the shaft is supported on bearings on both the sides(assume minimum friction), two 3mm thick circular plates hold the four tubes together at both the end. The shaft is attached to the center of the disk.

Data:

• Glass tube: 58 mm OD, 45 mm ID 1.8 m long
• Disk: 180 mm OD, 3 mm thick attached at 25 mm from both the edges of the glass tube.

Even a general procedure/idea of calculating torque requirement is appreciated