TWW Ferris Wheel Cat Scratching Post - Interactive Pet Toy for Climbing, Exercise & Weight Loss - Durable Cat Furniture for Indoor Play & Fitness

After all assembled, the main wheel wobbles a bit during use. It is not a precision fit between the main wheel and the foundation assembly. There is an inch gap from side to side between the lip (on the main wheel) and the wheels (of the foundation) it sits on. This may be to keep the foundation wheels from acting as shoe brakes on the larger wheel. However, the main wheel still tends to ride close on one side or the other. However, I believe the bouncing or wobbly spin comes from the small imperfections between the fit of each of the attached main wheel pieces (8 in all). Also, the wheels of the foundation have to be tightened to a certain degree so they don't come off. Even at minimum tightness, the wheels don't freely spin fast. Thus, with all these factors combined, the main wheel takes a little effort to get going and keep running. The wheel makes for a little of a bumpy, wobbly ride (as seen in the videos - that's just how the wheel rides even without a cat in it). My cat runs for a couple of minutes then quickly tires of it. This is the only one I've owned so I can't compare to others.This was a bit of a challenge to assemble, but it stays together well. The loves it!It was difficult to assemble. Several pieces inside had edges chipped off, and it was missing a critical bolt that made the whole thing impossible to use. I had to go to a hardware store and try several size bolts to find the right one to replace the missing piece. When I tried to get it from the manufacturer, they said they weren't allowed to send it out. Give me a break! I finally have it assembled and it isn't as smooth as it should be, and I am most disappointed.Cheap exposed back plastic construction, it's pretty good sized and a little wobbly at the top when going to speed. Mine had minor damage from shipping but still operational.Is a lot money ! Why!!?