A harvesting header includes a header frame, a flexible cutterbar assembly, and a plurality of laterally spaced apart support arms that are attached to and cooperatively support the flexible cutterbar assembly. The header also includes a draper assembly with a side draper carried on multiple ones of the support arms so as to flex with the cutterbar assembly. The side draper includes an endless flexible draper belt presenting laterally endmost margins, with upper and lower crop-conveying runs extending between the margins. The header further includes pivoting structure mounted relative to the header frame at a rear pivot location so that the pivoting structure projects forwardly from the rear pivot location.