I've only ridden in the rain twice in the last five years...but after each ride, I've pretty much taken the bike apart, cleaned it and put it back together. The first time nearly a 1/2 cup of water came out of the bottom bracket area when I removed it, which reinforced the need.
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2014 Specialized Roubaix2003 Interloc Impala2007 ParkPre Image C6 (RIP)