The Rubber Tire/Tyre Chunk is an item found on walks in Nintendogs + Cats, commonly in the Downtown route. It can be used as a toy, and can be recycled for items in Mr. Recycle. Like other materials, it cannot be sold.
3DS: "A chunk of rubber tire. Might come in handy sometime."
Where to findEdit
You are more likely to find a Rubber Tire Chunk on this route: