can I buy a road bike and replace the drop bars with flat bars? like a Trek Portland or surly cross check. *I'm wanting a quick and agile daily urban bike. *I've never owned a road bike and I want more of an upright mtn bike ride. * I test drove the Portland and a specialized cross bike over the weekend and the drop bars just feel so strange and not right. *will the geometry work if I just replace the bars ? *or should I be just restrict looking to bikes preconfigured with flat bars like the Gary Fisher Mendota or Specialized Sirrus or Masi Cafe racer. *any advice?