If you're looking for a bike shop in DC, you don't have too many choices. Fortunately, however, there is CIty Bikes in Adams Morgan. It might be a bit expensive, but the convenience makes it worth it. Located at Columbia Rd and Champlain (just north of the Columbia & 18th intersection), the bike store has everything you need, and service that's usually pretty helpful. They've also got decent store merchandise for those interested.
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