A road milling drum assembly that is for use with a road milling machine. The road milling drum includes a core portion carrying a first road planing bit assembly wherein the core portion detachably connects to the road milling machine. The first road planing bit assembly has a first milling width. The assembly further including one of the following components selected from the group of: (1) a protective cover that detachably connects to the core portion and the road milling machine; or (2) a milling extension segment carrying a second road planing bit assembly wherein the milling extension segment detachably connects to the core portion and the road milling machine. The second road planing bit assembly has a second milling width wherein the road milling drum has a milling width equal to the sum of the first milling width and the second milling width.