Originally Posted by
Al1943
The problem may be with the xx03 part of the model number. With Shimano 10-speed shifters the Ultegra and Dura-Ace shifters are double or triple specific, the xx03 numbers are triple specific (but can work with a double). xx00 Ultegra and Dura-Ace shifters are double specific. It's my understanding that the 5600 105 shifters are double/triple compatible and can work with any 10-speed Shimano drivetrain. But the Ultegra or Dura-Ace double shifters won't work with any triple crankset.
No problem with throw ratios between these.
The Shimano compatibility chart is conservative, there are some combinations that aren't shown to work but do anyway.
Al
Yeah, I specifically bought a 6603 shifter set though. It only lists that as being compatible with 6603/7803 front derailleurs, and the 5600 shifters only with 5603 FD's, which I find confusing. In fact, had I not seen that chart, I would've happily gone on and done it. Maybe I should just forget I saw the chart.