I am considering switching my old touring bike from a triple to a double compact crankset. Currently I have an Ultegra triple with an internal bottom bracket.

Searching eBay for compact cranks there are options for cranks which utilize both internal and external bottom brackets.

Am I correct in assuming I can easily convert an internal BB to an external one?

If so, would it be better than an internal BB?

I recently pedaled from Alaska to the tip of Baja and I'm foolishly considering riding the rest of the way to Tierra del Fuego some day. Assuming I'll have to replace the BB or crank at some point, would an internal or external BB be easier to replace in Latin America?

Finally, does anyone have any good experience or suggestions for reliable BB/compact cranks for a 12,000 mile tour? Are any better or more popular, I.e. Hollowtech, MegaExo, etc?

Sorry about so many questions, but I'd sure appreciate any help.

Thanks,

Pat