Low friction high speed roll door at high wind loads

A roll door movable between an open position and a closed position, the roll door comprising:

• a flexible curtain having a pair of opposed side edges, each side edge of the pair of opposed side edges configured to be inserted within a track member;
• at least one cross-bar secured to the flexible curtain, the at least one cross-bar extending between the pair of opposed side edges, the at least one cross-bar having opposed first and second ends, wherein the at least one cross-bar includes a hinge rotatably connecting a first longitudinal bar of the at least one cross-bar and a second longitudinal bar of the at least one cross-bar, the first longitudinal bar securing a first portion of the flexible curtain, the second longitudinal bar securing a second portion of the flexible curtain, the second portion separated from the first portion, wherein the first longitudinal bar secures the first portion of the flexible curtain at a first slot and the second longitudinal bar secures the second portion of the flexible curtain at a second slot, the second slot formed between a front piece of the second longitudinal bar and a back piece of the second longitudinal bar;
• and
• at least one roller secured to each of the opposed first and second ends of the at least one cross-bar and positioned to move along inside the track member as the roll door is moved between the open position and the closed position, wherein a shaft of the at least one roller is secured to a back piece of the first longitudinal bar or the back piece of the second longitudinal bar of the at least one cross-bar.