In bearing selection you need to consider the following ones and reply the questions respectively :

For the Shaft Size

•  What is the shaft size at each bearing location?
•  Is the bearing on a stepped shaft?

 For the Speed

• What is the shaft speed at the bearing location?
• If belt driven, what is the motor speed and the sheave diameters?
• If direct drive through a reducer, what is the motor speed and the reduction ratio?

 For the Loads

• What is the radial load that the bearing will be required to support?
• What is the axial load that the fixed bearing will be required to support?

 For the Environment

• Are the bearings in a wet environment?
• What is the shaft temperature at the bearings?
• What is the ambient temperature around the bearings?
• Are the bearings in any contamination? If so, like what?

 Current Bearing Life

• How long do the existing bearings function?
• What bearing life would make you satisfied?