jinsc

Actually, it does decrease friction as well as reduce belt skipping. Once the “meshing and un-meshing” of the pulley to the belt is complete (which occurs only at the top and bottom of the pulley), in-between this area is more or less in static (not moving) contact which introduces virtually no additional friction to the drive train. The increase diameter will aid in efficiency because the belt doesn’t have to bend around as tight of a radius. A significant amount of drag in belt systems is caused by this. In addition, in the event of potential skipping due to heavy load, the belt would have to stretch more to clear the larger pulley diameter which inherently reduces the likely hood of skipping. Also, the larger diameter pulley will of course increase the number of teeth holding the belt which also helps to reduce potential skipping.