Description of ribbed belt drives
Ribbed-belt drive

The belt path is defined by the positions of the pulley centers and their pitch radii, and by the position of each pulley relative to the belt (inside or outside). The belt is in contact with the pulleys at the points of tangency where the strands are perpendicular to the radii. Contact can take place on the V side (in the case of pulleys) or on the back (in the case of idlers and tensioners). The drive pulley is marked 1, while the other pulleys are numbered following the belt in a counter-clockwise direction (figure 5 ).