The Dog Tire Jump has a metal frame and comes with two inflatable tires. One tire has a 20" inside diameter and the other is 22". There are two ways that you can adjust the height of the tire when it is on the jump. The first is with poles that are provided that attach to the tire and rest on little supports on the frame. Using this method, if the dog hits the tire when it jumps through, the tire will fall.
The second is with the ropes provided with the jump. The ropes attach to each corner of the jump and feed through pulleys on the frame. To adjust the height of the tire, you just move it up or down within the frame. If the dog hits the tire with the ropes on it, it will not fall.