Originally Posted by
KD5NRH
...no 8sp shifters for it were available locally) and SunRace triggers on.
Don't understand. Is the rear shifter 7-or 8-speed?
7/8 mixes are quite known to kinda-sorta work. At some level of wear, tune and cleanliness they run OK. But rarely over the full range of expected Life.
If a matched system shifts OK when going to bigger sprockets, but poorly when going to smaller, it's very often caused by excessive Cable drag. Clean and lube the Cable guide under the BB Shell.