I always thought a worn chain was just a worn chain until a customer in Denver proved me wrong

Last month, a guy brought in his gravel bike with a skipping 11-speed drivetrain. I measured the chain, it was at 0.75% wear, so I told him he just needed a new chain. He insisted I check the cassette too, and sure enough, two cogs were visibly hooked. He said, "A new chain on a worn cassette is just a band-aid," and he was totally right. I swapped both, and the shifting was perfect. Has anyone else had a customer point out something obvious you missed?

3 comments

3 Comments

morgan.logan21d ago

Made the same mistake myself a while back (story of my life). Told a guy his chain was fine, turns out I was the one who needed a basic lesson in "maybe don't trust your eyes when they're covered in grease".

allen.ivan1mo ago

Gotta disagree here, the customer got lucky with his guess. Most of the time a chain at 0.75% is the whole problem. Telling a mechanic to check the cassette for every slightly worn chain just wastes everyone's time and money. You fixed it right in the end, but he was just pushing for a more expensive repair without real proof until you looked. Sometimes a worn chain is just a worn chain.

wesley_martin1mo ago

My shop in Boulder had a regular who rode his mountain bike hard in the mud. His chain was shot, but the cassette looked fine, just dirty. We put a new chain on and it skipped like crazy on the middle cogs. Cleaned the cassette properly with a brush and solvent, and the skipping stopped. The grime was so packed in it was acting like worn teeth. Now I clean first before I even pull out the chain checker.