Those plastic wheels are horrible for several reasons. When i took in my first chin and didn't no any better, he came with that same wheel. He would chew on it a lot, which is rly bad cause he could ingest that. Which can cause health problems. Since the middle support bar thing is plastic as well, when the wheel moves it is plastic grinding on plastic. If you take it off after a while, you will notice a plastic powder. Both you and your chin don't want to be inhaling that. Also, if you watch the chin move on it you will notice that it puts his back and spine at an unnatural angle which can cause harm as well. Then there is the simple fact that you keep having to replace the wheel.
So its definitely better to get a new type of wheel. The type will depend on the room you have in the cage, money willing to be spent, and your preference. Like Mgonya said, i to prefer the metal flying saucer.
Copied from a difffrent post i made in another thread:
I prefer
this flying saucer wheel. They are expensive, but they should last for a long long time. Its not plastic, so the chins cant rly chew them. And they wont degrade into plastic dust over time.
They come fully assembled so all you have to do is attach it to the cage. They allow a chin to reach full extension while running, as if they they were actually running around. Alot of the round ones (shaped like a mouse wheel) force a chins spine and body into unnatural positions. This saucer doesn't.
And should something go wrong with your wheel, its a extremely high probability that its just a bearing that got worn or dirty. Good thing about that is, not only is it a simple fix, but that company sells extra bearings for like $2. The wheel also comes with instructions on how to change a bearing should the need ever arise. Of the 2 wheels i have now, one i had to replace a bearing (bought that wheel used) and the one i bought new has yet to need any work after 4~ years.
They come in three sizes. Small Standard and Large. I prefer the large wheel. It gives them the most room to extend their body freely. But it will depends on the type of cage you have, and how much room is available. One other side note; They stopped making the large wheels technically. But if you email them, they will probably agree to make you one. (I just emailed them recently about it, and they said they could make one for me)
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Good news, it seems the large version is back on there site again. So i guess they had a lot of requests for it!