On my new sport utility bicycle I can cart groceries, take my kids shopping, haul a barbecue grill and make a margarita.

By Mark Benjamin Salon

Enter the sport utility bicycle, a long bike nearly as dexterous as a conventional bike but with a remarkable capacity for cargo, whether that means lots of stuff or people. I recently turned my mountain bike (a Specialized Rock Hopper) into an SUB with a frame extension called the FreeRadical ($490), made by Xtracycle, a small, quirky and ingenious company based in Oakland, Calif.