I firmly concur with pneumatic tires (in particular
AM-0970's due to the simplicity of getting them to work with standard FRC hardware) as the best answer for concrete and most outdoor surfaces. Unless your outdoors has significantly less sand and gravel than the north shore of Lake Pontchartrain, don't even think about using the same wheels for indoors and outdoors. (Personally I'd like to carry a spare set of shoes everywhere so I could swap as I walked outside and inside.) You could possibly swap all the wheels every time you move in or out, but we have pretty much opted to have inside robots and outside robots.