Example roll-up doors are disclosed. An example roll-up door includes a track system and a curtain. The curtain blocks a doorway when a leading edge is at a closed position and unblocks the doorway when the leading edge is at an open position. The roll-up door further includes a track roller to vertically travel along a track system. The track roller is to be rotatable relative to the track system. The roll-up door also includes a windbar to be coupled to the track roller. The windbar is closer to the lintel when the leading edge of the curtain is at the open position than when the leading edge is at the closed position. The windbar is to be vertically movable with the track roller and to be rotatable relative to the track roller and rotatable relative to the track system.