I don't know what type of tire the BOB comes with these days, the one that came with mine was a knobby tire that required a jackhammer to remove. I replaced it with a schwable, which was "OK" barely "OK". After it self destructed I got a Maxxis Hookworm which has been one tough little tire, it's 1.95" and 110psi Max. This is my recommendation. Also if your bike has presta valves, this is a good time to switch to presta on the BOB so that you have the same valve on both. You will just need the tube adapter, a little ring of aluminum for the thinner valve stem. Here is a good source for trailer tires and other BOB accessories, good prices too.
http://biketrailershop.com/catalog/i...52bd919e993537
For some BOB modifications check these links out.
http://www.crazyguyonabike.com/doc/p...e_id=9173&v=5l
http://www.crazyguyonabike.com/doc/p...e_id=9172&v=5j