A belt having a longitudinal direction extending around the first wheel and the second wheel and forming a closed shape with a circumference in the longitudinal direction. The belt has a first rigid portion and a second rigid portion each extending from the first wheel to the second wheel. The belt may be included in a drive mechanism including a first wheel, a second wheel. Accordingly, when the first wheel is rotated about its axis of rotation the rotation causes movement of the belt along the longitudinal direction such that the first rigid portion provides a pushing force on the second wheel, and the second rigid portion provides a pulling force on the second wheel. Drive mechanisms may have a longitudinal gap between a belt and wheels of the belt. Belts may have a v-shaped or arcuate cross-section. Belts may have multiple layers.