Originally Posted by knucklesandwich

You might manage to squeeze 28’s but you probably won’t be able to find a knobby tire that will go. I’d look for something with a slightly inverted tread like a Panaracer Tserv, or one of the Schwalbe trekking tires in a 700x28.

Best bet might be to hit your LBS and see if they’ll let you size up a couple before you make the plunge.