Life Outside of a Bike Store

My neighbor pulls me aside last night to talk to me. I had no clue as to what he wanted to share, but the look on his face was concerning. I steadied myself for whatever was coming next be it family, house, work, etc…. I was kicking myself for not having had that pint before going outside. In dramatic fashion he told me that the drive train on his mountain bike was skipping. It was really bothering him and sapping his performance. I’m looking at him bewildered. It’s 8pm and not only am I off the clock, but completely sober. I give my probable diagnosis and as quickly as he had gotten my attention he was gone into the night.