The entire frame is solid and no soft spots or crunchy regions. But, the bottom bracket paint shows some lifting or some kind of crust forming under the paint, and the cable brackets (which I have heard are aluminum bonded to the frame) are peeling like mad. Mostly concerned with figuring out what is with the mottling forming under the paint on the BB? Anyone?
The BB area has the patterns of galvanic corrosion. https://fastenerengineering.com/a-coating-for-galvanic-corrosion-prevention/ . Moderne frames are constructed with layers of fiberglass at bonding interfaces to prevent galvanic corrosion but I don’t know when this practice started. Certainly the original carbon frames where carbon tubes were bonded in alloy lugs suffered from significant corrosion issues.
very nice, and I have no reason to doubt your assessment. It makes sense, now that I have looked it up and done some web searching. Thank you, very much.
The Aluminum cable guides appear to be suffering from the exact same thing.
so, how do we feel about this, especially on the BB? alarmed? or is it just an inconvenience on a bike that is going to see light duty for the rest of its life?