Any Issues installing STI Brake/Shifter levers to bike with direct-pull V-Cantilever brakes? I want to install drop bars in my hybrid bike and also thinking of getting STI brake/shifter lever. The bike has V-Brakes. Is there any issues on doing this that I should be concerned about?
Standard V brakes do not work well with STI levers, they don't pull enough cable to allow the V brake to be setup properly; you end up with the pads so close to the rim that they are always rubbing on it or needing to be adjusted and the braking can also be poor.  

I know of 2 options to get around this, you get a V brake Travel Adjuster or Travel Agent - essentially a pulley that increases the amount of cable that is pulled by the STI shifter or you get some 'Mini V Brakes' as these have a shorter arm and so work with the STI shifters.