Plays in traffic
Join Date: May 2006
Location: Rochester, NY
Bikes: 1996 Litespeed Classic, 2006 Trek Portland, 2013 Ribble Winter/Audax
I agree with all the adjustment suggestions so far, and have one to add. If the chain is too long, a downshift to a smaller ring can throw it off the inside. A couple of links can make a world of difference. Removing 2" of chain from one of my bikes completely eliminated the problem, without touching the FD or its adjustments.
As for Sora vs. "better" groups, I have an 8-speed Sora bike and a 10-speed 105/Ultegra bike, both with triples. The Sora bike shifts better at both ends.
This is probably due to using R-500 shifters instead of the 3300 shifters. These shifters are supposed to be Ultegra-grade, and indeed, they feel like the 6500 shifters on my Ultegra/Dura-Ace double bike. From this, I'm beginning to think it's the shifters, not the derailleurs that make the difference in shifting feel and smoothness.