Surprised you couldn't find some sort of rear tire in Colombia ?? Generally best place in S. America for tires at reasonable prices. Doubt you would find Mitas, Mefo or K60 but usually a few others to choose from. Just about any new rear (non knobby) would have got you to US border. Some guys bought some long wearing Kendas, IRC, Duro, ChengShin, in Colombia. Also some Pirelli, maybe Metzeler. Not sure about TKC, but not great choice for rear ... will be gone in 3000 miles or less. (so you might make USA on that??) Hope you get time to make it over to the Caribbean side of Cent. America. Beautiful.