EDIT: Answer at the bottom
I have an issue with the shifting for my bike, a Giant TCR C1. It seems like the shifters for the Giant TCR work only with one 10s wheelset but not with another 10s wheelset.
I have 2 bikes: a Giant TCR C1 & a Cannondale
Giant TCR C1:
Dura-Ace 10s Shifters
Ultegra 11s Crankset
Ultegra 10s Chain
Dura-Ace 7800 Rear Derailleur
Cannondale CAAD9 R5:
Shimano 105 10s Shifters
Shimano 105 10s Crankset
Shimano 105 Chain
Ultegra 10s Rear Derailleur
I have 2 wheelsets: an Ultegra wheelset for my Giant TCR and a Shimano wheelset for my Cannondale. I'll be referring to the latter wheelset as my Cannondale wheelset.
When I put the Cannondale wheelset on my Cannondale, the shifting works fine. Same for when I put in the Ultegra wheelset. I don't have to adjust the barrel adjuster to adjust the position of the chain.
When I put the Cannondale wheelset on my Giant TCR, the shifting works fine also, albeit a bit more slowly on the descent from the biggest cog down to the small cog. However, when I put the Ultegra wheelset in, the shifting doesn't work properly. I have to adjust the barrel adjuster to align the chain with the cassette, and even then the shifting isn't smooth. It goes up fine but doesn't come down smoothly. It gets stuck in the biggest cog until I shift twice; then, it jumps the second-biggest cog and lands on the third-biggest. I adjust the barrel adjuster so that it descends properly, but then it has problems with shifting upwards, getting stuck on the smallest cog until I shift twice and then it goes up to the second cog.
I had initially thought it was an issue with the shifters, 11s crankset, rear derailleur, or possibly the rear derailleur cable, on my Giant TCR. However, the shifting works fine when I have the 10s Cannondale wheelset on the Giant TCR, so those are not it.
The Ultegra wheelset had originally had on it an 11-speed cassette, which I've swapped out for a 10-speed cassette. I had also initially thought it was an issue with the cassette, but the shifting works fine on my Cannondale when I put on the Ultegra wheelset with the 10-speed cassette, so I don't think it's an issue with the cassette.
Does anybody have an idea on why this is happening?
It turns out that the issues were with the rear derailleur cable and the rear derailleur. The cable was bent in two places and the derailleur was either incompatible with the brifters or not fully functional. I've replaced the rear derailleur cable and swapped the Dura-Ace 7800 derailleur out for a Dura-Ace 7900 derailleur and the shifting has started working smoothly.