I went to the shop to install a new compact crankset, and the mechanic could not keep the original tiagra triple FD. We tried every configuration of HI, LOW screws, moving the FD down as far as possible, tilting it, etc. But we just couldn't get it to shift adequately for all the gears. Then he showed me the 105 double FD and pointed out the differences, the 105 double FD's side walls were smaller in height, and the distance between the walls were smaller as well. When we put it on the bike, it shifted great.
I just want to pass this information on, because i was suggested that changing the FD would not be necessary. However, it seems that in order for the bike to shift without any problems then changing the front FD is indeed necessary.
Anyone have similar experience?