So I've searched and I can't seem to find any threads on the specifics of routing cable internally. i have some tektro rx 4.1 brakes. So do I drill a hole near where I mount the bars to the stem, and another near the end of the horn for the cable to go in? If someone could clarify or post a crude drawing that would be helpful.

cable comes out where it needs to, the less drastic the bends in the housing the better. for reals, just get time trial levers and drill a hole near the stem.

where does the cable go in though? from the TT brake that is

they replace the end cap and the housing just shoots straight into the bar.

Any removing metal from bars near the stem sounds like a bad idea to me... If it has to be internally routed, I'd have it come out of the bars as far up the bars as possible, and not in the middle of any point where it bends or changes diameter.

buy bullhorns that are drilled for internal routing. probably easier than drilling, and no worries about compromising the structural integrity of the bars

if you play with the routing and the tape a bit you can get it so that it's more comfortable with the cable on the outside most places anyway.

I've had bars that had been drilled for internal cable routing and it always made me wonder when pulling on the bars to sprint or whatever so I wouldn't do it.YUou can probably route the cable under the bar adn tape over it and it will look ok and won't bother your hands