There's something gratifying about buying a bike bag that's been, as the Web site attests, "created to endure biking 10 hours a day in the rain, mud, snow, and grit," even if the most cycling you ever do is from your front door to Muni. Local manufacturer Chrome designs and makes its bags right here in the city of ŸberÐbike messengers, and these cargo carriers are created to kick the asses of their nearest competitors. We're talking military-spec seam binding, Cordura shell, weatherproof truck-tarp liner, foam-padded shoulder strap with cross-chest stabilizer, and a seatbelt-style buckle that clicks so solidly that you feel like you're tucked safely into something, even as Mr. Minivan careens into the bike lane. The double-strap backpack-style bags feature a molded back panel, and roll-top bags create a watertight seal and feature an outside wet-dry pocket. And, of course, they're incredibly cool-looking — but we won't tell anyone that's actually why you bought one.