• deejay4am@lemmy.world
    link
    fedilink
    English
    arrow-up
    3
    ·
    1 year ago

    You wouldn’t be able to lift the door without the spring acting as a counterweight. It’s usually a big roller just above the doorway on the inside (right near where the track curves in) with cables that run down to the bottom door panel.

    So yeah, huge spring under constant tension.