My 18' Wheels

Ok, I currently have 4x18' wheels at about 200pds (alittle more actually) yes those are some heavy wheels and I want to replace them. A dumb question but can I replace them with any 18' rims or are there specifications?

you need ones that are the right bolt pattern, close to the same offset and width, and if you want them to balance properly, the correct hub-circle size.

Thanks. ;)