An agricultural harvesting machine including a flexible cutterbar (22) and associated draper belts (32) for carrying cut agricultural material to a center location. The belts (32) are guided by a drive rollers and idler rollers. The idler roller for each belt (32) is pivotable about an axis generally at 90 degrees to the axis of the belt and the drive roller for each belt is translatable axially to minimize diagonal stresses caused by flexing of the elongated endless belt. A spring assembly (98) is positioned on a frame (26) for the machine and acts to yieldably urge the drive rollers (70) in an aft condition to alleviate stresses for an extended period of operation.
