The very foundation we were built on. The State Bicycle Co. Core-Line of fixies and single speed bikes are proudly crafted with steel and tastefully designed in a singular-color way. The 4130 Core-Line is the Core-Line's heavily upgraded relative, featuring 4130-grade chromoly steel, sealed hubs, lighter-weight components, and double-butted tubing, combined with designer colorways not seen anywhere else.  We produce each bike model in a limited quantity and then retire them for good once the last bike leaves our warehouse. Trust us: once they're gone, they're gone.