Tried the zip tie chain trick on my commuter and now I'm missing 3 links
Saw a guy on YouTube say you can fix a slipping chain by zip tying the derailleur cage forward, so I tried it on my 2011 Trek in the garage last Saturday. Rode 2 blocks to the store and the zip tie snapped, whipped the cage back, and bent my hanger. Cost me $24 for a new hanger and an hour of walking the bike home. Turns out zip ties don't hold under load, who knew. What's the actual right way to check if a derailleur hanger is bent without a $50 alignment tool?
You can get pretty close by flipping the bike upside down and using a long straight edge or a spare wheel clamped in the dropouts to eyeball the gap. Hold a ruler against the side of the rim and see if the hanger pushes the derailleur in or out as you spin it.