Flats to drops with discs
Not necessarily. If you fit bar-end shifters, you can have drop-bar brake levers, specifically Tektro RL520 brake levers, that pull enough cable to operate V-brakes, and also the specification of cable disc brake used on flat handlebar bikes. Do that and your brakes will be just as great as they already are.
These brakes are more efficient than any road bike brake purely on account of that extra cable travel, which reduces the cable tension, hence less friction and cable stretch. And what little stretch remains becomes an even smaller proportion of the increased travel, so the brake can be designed with even more leverage. A win-win-win situation!
Fit road STI controls and you must also fit road-type cable disc calipers. They’re okay, but prepare to be disappointed by the drop in performance compared to your existing flat bar set-up. If you’re sold on ‘brifters’ but want to keep your brakes as they are, consider Gevenalle (formerly Retroshift) CX-V controls, which integrate bar-end shifters with RL520 levers.
This was first published in the February / March 2015 edition of Cycling UK's Cycle magazine.