[Al Skierkiewicz]

Indie,
Even I am a little confused. It sounds like you have the motor driving a simple two pulley belt drive where the belt is actually the conveyor belt. From what you said i gathered that the frictional forces at play on the pulley shafts and side load on the bearings are the significant frictional forces and I would agree with that. Remember that the conveyor belt moves because it has a high friction coefficient with respect to the surface of the pulley. Since one of the pulleys is driven by the motor, the pulley/belt friction is a small part of the overall load placed on the motor. The greater frictions are those produced in the pulley bearings by the tension of the conveyor belt and whatever load is actually placed on the conveyor, i.e. that material that is moved by the conveyor. The friction on simple sleeve bearings skyrockets as the belt tension is increased. It is for this reason that many belt systems use better bearings (roller or ball bearings) to minimize this friction. If one of the pulleys is on the motor shaft without the use of external bearings, expect high friction at the motor bearings perhaps resulting in motor failure. I saw at least one robot in competition using the chalupas with chain sprockets attached to the motor shaft. The resulting forces tore those motors apart in one day.
Your question on measurements 0z/in oz-in is correct, they are the same.