Drivetrain

External or Internal?
The question should really be bombproof or vunerable?

Seriously for the ultimate bombproof bikepacking drivetrain you can't go past a Rohloff Speedhub. I've used various drivetrains over the 22 years that I have mountain biking. Thirteen of those years has been on a Rohloff Speedhub. None are as reliable or shift with consistency in ALL weather conditions as well as the Speedhub. I've toured countries, raced various endurance mountain bike races and racked up excessive commuter mileage on a Speedhub and I'm yet to find its equal. Yes, there are other lighter drivetrains out there. Yes, there are cheaper drivetrains out there. If you want a drivetrain that will continue shifting mile/kilometre after mile/kilometre, no mater where in the world you are, no mater what weather Mother Nature is throwing at you, get a Rohloff Speedhub.