I believe the first ones were steel (Perhaps they were using up the NR ones?) and then alloy. It gets even murkier as the Victory ones used gray pads and shiny tire guides and I just bought a set of Cobalto carriers and pads that have the cream colored tire guides. I think there were even two versions of these. I have noted that Cobalto calipers that use the black rubber washer like thingy (Don't you love it when I try to get this technical?) by the adjustment nut had black tire guides while the Cobaltos that used the cream colored ones had cream colored tire guides. How many Angels could dance on them is anybody's guess. Tom Sanders (whose strong point sure ain't technical) Lansing, Mi