I have a 6" x 2" poly contact wheel that I purchased back in April, 2009. I haven't used it in a couple of years and it sits on a shelf under my workbench. When I went to pull it out today I noticed that it felt sticky/greasy/dirty all at the same time. When I started trying to clean it up I noticed that the hub was loose and then that the wheel (the poly part) was beginning to fall apart. Is this common for these types of wheels? It does sit in my shop which is not climate controlled but I haven't had any problem with either the 10' or 2" poly wheels that I have purchased over the years.