[Tristan Lall]

PVC won't be very good as a bearing—it's weak and soft. Besides, only specific types of PVC are allowed, so you'd be stuck machining your bearings from PVC pipe and fittings (and fasteners, if you can find any, and the above theory holds). (That would be unbelievably annoying to make.)

If you're referring to using PVC as a roller or sliding plate without a bearing, then I think it ought to be a bit better than polycarbonate.