Yo, Jan.
If you approach the Rohloff cabling choice from an engineering rather than a historic-cycling viewpoint, the answer is obvious. The internal cabling arrangement is a throwback to the road-bike practice of part-exposed cables. It is suitable for old road frames being converted to Rohloff use. It's a pain to fit new cables and a bigger pain to disassemble beside the road if a cable should break, especially if the cables have corroded into the connectors; little grubscrew are actively rider-hostile on a bike! But it makes roadies feel comfortable with the appearance of the bike because the cables run along the top tube and down the chain stay, and it comforts them to believe that the bare wires for part of the run save five grams of weight.
The external gearbox is a proper blank sheet engineering extension of the Rohloff principle. Note that I don't say "solution". The open cables is a "solution" to a question that shouldn't have been asked (what would make roadies happy? how can the gearbox be fitted to existing frames that are quite unsuitable for it?). The external cables are fully enclosed for their entire run. They end in a box that is removed with a thumbscrew when you want to remove the wheel.
Rohloff provides mountings to the hub to fit the EXT clickbox behind the hub and sticking up into the air -- for those foolish enough to continue running the cables in the traditional place. This position could theoretically be more vulnerable, though I'd ask your informants for examples as I am not aware of any EXT boxes being smashed on the hefty steel plate to which it fixes. (In my opinion, its "vulnerability" even in this position, is BS.)
However, Rohloff also provides mountings to the hub for a very straight run under the bottom tube and chain stay and directly into the clickbox tucked out of the way underneath the hub and chain stay. This is an ideal run that suits the Rohloff. I don't see any bends on Rohloff cables that are thoughtfully installed on purpose-made bikes which are sharper than cable-bends on any other bike; it's the desperate rearguard argument of people trying to protect a convention long outworn.
I don't know why anyone would recommend the internal gear mech on a Rohloff. It makes no modern sense on the sort of bike on which you would use a Rohloff gearbox, except to roadies, and even for them it more of a psychological security blanket, more about appearances than an engineering necessity.
I believe I was the first to notice (or at least to say out loud) that the service requirement of the EXT gearmech of 500km is excessive for on-road use, and the first to pump it full of Phil's grease as an (ongoing) experiment to determine whether the service interval can be extended to the same 5000km as the gearbox oil change. Presently it seems like Dan will reach the 5k first and report before I can, but I expect the answer to be a resounding "yes", even in the very demanding conditions in which Dan tours. In any case, even if you are an obsessive stickler for "the rules", and service the EXT box every 500km, it is, literally, a 10 second operation: put the rotary control in top gear, undo the thumbscrew, pull the EXT box off, give it a wipe with a tissue, give the bikeside brass fittings a wipe with the tissue, squirt in new grease, push the EXT box back on, twist the thumbscrew. It takes longer to read the description than to do it.
Andre Jute
