I use velcro cable straps, like you use for storing extension cords and the like. I have them attached to the cross piece of the bottom of the crate so they line up with the main bars of the rack. Two on each side bar and one at the rear end of the rack to keep the crate from sliding forward. Once I got everything lined up, it was fairly easy to take off and on. No tools and it won't rust. I carry a u-lock, lunch and a pretty heavy laptop backpack in the crate and haven't had any issues with the crate moving around.