Spent 3 evenings chasing a rear derailleur ghost on a 2019 Trek FX, and it was the hanger the whole time
Customer brought in a 2019 Trek FX 2 last week saying it shifted fine in the stand but skipped under load on the road. I did the usual dance: new cable and housing, checked the cassette wear with a gauge (it was fine), reset the limit screws, checked the B-gap twice. Still skipped in the middle of the cassette on a test ride around the block in Bellevue. I got stubborn about it and went at it again after close on Tuesday, then Thursday, so I burned maybe 4 or 5 hours total across three nights. Finally put the Park hanger tool on it and the alignment was out maybe 4mm at the dropout. I felt like a dummy because I keep telling the younger guy at the shop to check the hanger first, but I skipped my own rule. Straightened it in a few spins of the tool, test rode it, and it was silent. Any of you have a go-to order you run through that keeps you from skipping the obvious stuff like that?
The "skipped my own rule" part got me. I had a bike come in with a squeak that I spent way too long on once, turned out to be a loose bottle cage bolt that only rattled at a certain cadence. Drove me up a wall for two days and the fix was ten seconds. Now I shake every bike before I even put it in the stand.