Bests & Worsts Reviews from Amazon

This is very sturdy and looks like it would work great. BUT it doesn't. The design is all wrong. Which seems impossible since it's so simple! But we have 4 cats that love running wheels and NONE of them will use this, and in fact it scared/hurt a couple of them. First: The wheel is just too small for an adult cat. A kitten could use it to some degree, but still could not "run" on it, just walk and maybe trot safely. The angle of the curve is just too sharp for even a small adult cat to make use of it. You can see this in the first pic of the orange kitty, he's considered a small cat and the angle that he has to arch his body to move on the wheel is just not physically comfortable and he definitely can't run in that position. Second: The track is too narrow. My cats are all on the small side and kept falling off the track. They already have a One Fast Cat wheel so they know how to use cat wheels, but they could not make this one work without repeatedly slipping a back leg off the track, requiring them to stop or they entirely fell off and had to start over. Third: The bolt that the wheel spins on seems like a great idea, but it's so smooth that there's almost no friction on the wheel. This makes the wheel spin too fast as soon as the cat starts walking, so they get off balance because of the aforementioned sharpness of the curve, and have to hop off or get flipped inside the wheel. They don't like that. Fourth: The carpet inside the wheel seems like a great idea - but it's actually DANGEROUS. It catches their claws easily and when the wheel spins too fast, as described above, their paw gets twisted and dragged over the top. This causes them to have to rip their claw out of the carpet or it gets twisted and they get hurt. This happened to all 4 of the cats that tried it. ***I uploaded a pic of the orange kitty getting stuck in the carpet and getting his claw twisted up, having to rip it out forcibly. He never got on the wheel again after that incident, as far as I could tell. Fifth: The carpet on the outside seems like it would be cool for them to scratch and claw, but the same thing happens, as above. As soon as they put their claws into it, it spins, and pretty fast, dragging their claws with it, causing them distress. All 4 cats absolutely love their One Fast Cat wheel, they take turns running on that thing all day long, so I thought a different wheel would be as fun for them. But they all tried it a couple times each, with each of them having a difficult time or a bad experience, and never going near it again, after the first two days. I left it with them for 5 more days, and they avoided it like the plague. The moment I gave them back their OFC wheel, they were running like crazy again. Guess I'm buying one more OFC wheel and this one goes back. Too bad, I wanted it to work. Maybe they will redesign it with these things in mind. Until then, I cannot recommend this wheel from Penn-Plax.