jppe,
Please get the bicycle checked in Colorado with the descents you will be taking. A transient noise is so frustrating but I remember what a man told me about mechanical things, they don't heal up.Some thing is making that noise. maybe its nothing or the water bottle fitting but wouldn't want to read about you road rashing the bicycle on your trip. Have a great time too!!!
Bill
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Semper Fi, USMC, 1975-1977
I Can Do All Things Through Him, Who Gives Me Strength. Philippians 4:13