Over tightening the Quick Release skewer will push the derailleur cage out of plumb, and cause poor shifting.
This problem is a result of over tightening the quick release skewer. The derailleur hanger is directly adjacent the dropout on the drive side, and over tightening the skewer forces the chainstay to roll and flex rightward. While the degree of movement is very small, it’s amplified at the end of the derailleur cage to the extent that it behaves like a bent derailleur hanger.
If you’re certain that your derailleur hanger is straight (by checking it an alignment tool and your regular wheel), then the next likely culprit is that you’ve overtightened the skewer.
This is extremely common on bikes with quick release skewers, not only on indoor trainers, but on the wheels outdoors as well.
Steps To Resolve
- Pull the quick release lever and loosen.
- Hold the lever about 2/3 of the way closed, and turn the nut on the opposite side of the skewer until you begin to feel tension.
- Close the quick release lever the rest of the way. You should not have to exert much effort to close the lever. If you use more than just your thumb, the skewer is probably still too tight.