I've been using it as a double for about 2,000 miles, no problems. I left the spacer on the shaft, which makes the 39t ring my main cog, with the 50 coming into play at higher speeds. I also have the original triple FD, which works OK, but I think a dedicated double FD would be better. In any event, I plan to swap in a dedicated double crank and FD one of these days. I have another bike that can use the 105 trip. That would be Granny's Trek.