My co-worker decided to start doing sprint races and picked up a circa 2000 Cannondale Multisport for $300. The previous owner didn’t ride it much but also didn’t take care of it. Upon inspection, there appears to be corrosion under the paint starting from where the paint was chipped and at the top and bottom of the head tube where there was no paint. It looks like veins or spider webs. The corrosion isn’t very bad. Is this going to be a safety issue? Should she do anything to keep it from getting worse - aside from general cleaning and maintenance?
Aluminum alloys oxidize differently than steel, so you should only see oxidation if there have been knicks, ding, or cracks in the frame or if you live near a large body of salt water, ride on salted roads in the winter, or never give your frame an occasional wipedown. Clean the areas really well, maybe with a green Scotch pad, if needed, to get any “3D” oxidation off the frame, particularly around the chipped paint areas. Don’t worry about chipping a bit more off in the process (not that you should peel it off in sheets, though). Verify that it is only oxidation and not cracking. If you live/workout in the harsher conditions I mentioned earlier, you may want to look into clearcoat and/or touch-up paint. Otherwise, if it isn’t cracked, go ahead and ride!
This is a very common issue on Alum Cannondales. I have painted many and with the exception of the one that were brand new they all had bad corrosion under the paint near the bottle bosses, cable guides or anywhere else that got chipped. None of the frames were damaged to the point of being a structural issue but the metal sure did get pitted. I painted a six13 recently that had this issue starting at the top of the seat tube. Looked like a small bubble in the paint but was corrosion down to the TT and the paint came off in sheets when I started stripping it. White corrosion under all of the paint.
Koz, PaintIt - Thanks for the great info.