Great product but no assembly instructions. Your floor will buckle and your house will collapse before these heavy casters fail. However, the instructions recommend mounting at the bottom of the spars by "removing the alignment rails and guide inserts from the underside of the spars with locking pliers or similar tool (inserts are pressed in)". This is not advisable as press-fits are very strong and strong and the gripping surface for each pliers is thin. I've successfully used a piece of metal reinforcement in the tube to *knock out* the pressed-in slide inserts. I would recommend: unscrew the leveling guides (rubber feet), put on heavy gloves and use a metal rod longer than the posts to carefully knock out the slide insert (silver stamping). Work slowly to remove the slide insert in a dozen pulls rather than one hard pull. The instructions are also inadequate for inserting a roll. I nailed the vertical support to the roller with a (sacrificial) piece of scrap wood to protect the top of the vertical support. Don't damage this top as it has threads that mate with the top of the brace. Hope that helps!