One-piece wheel is made in monoblock, which is simple and easy for maintainance, but kind of dull. Two-piece rims and three-piece rims are usually made in stranger shapes, which look fashionable and novel.
An one-piece wheel is made in a single piece, usually by casting, so it’s also sometimes called monoblock wheel. One-piece wheels have the advantages of being simple, light and cheap.
The two-piece wheel have two pieces that are attached to each other by welding or with bolts, consisting of the face and the barrel. It can be flexibly constructed to varied offset or backspace. The main advantage of a two-piece wheel is that if any part of it is damaged or bent, this part can be replaced and the other part can be remained, which to some extent save money.
Three-piece wheels are the same as two-piece wheels except that the three-piece wheel consists of two barrels and one face. As it can be separated into three parts, it’s easy to be modified by just replacing or changing one of those parts.