Fishing Rhino is spot on. Dry Rot is the issue before tread in most cases. Getting 2 new tires/wheels as needed while keeping the survivor as a spare is a great way to do it.
I've purchased from recstuff.com before. They carry Kenda tires and they've had some real good prices when I bought.
Looks like they have both the 13" and the 14" in stock.
recstuff.com/13-Inch-Radial-Trailer-Tires.aspx
recstuff.com/14-Inch-Radial-Trailer-Tires.aspx
Also...trailer tires are the way to go before car tires in my opinion. Hope this helps...don't forget to wet a line.
