I’m not mechanically inclined and always prefer Ernie to work on my bike. But I do know if I intend to race solo, I’m responsible for understanding the basic way something moves and works. Some major items on my “learn” list included: 1. mounting, seating, patching, and sealing my tires and tubes 2. learning how to break my chain and make the bike into a single speed, in case something happened to my rear derailleur 3. running through how to diagnose the basic issues of Di2 systems, including understanding all the junction points and how to replace an e-wire should one get damaged 4. how to remove a broken spoke and attach a “fix-a-spoke” should something happen to my wheel During my first ultra cycling event @silkroadmountainrace I knew I never wanted to use mechanical shifting again. I promptly switched to Di2 after and haven’t gone back since. Di2 saves my hands — my left hand, especially. When riding hundreds of miles over rough terrain, shifting to the big ring with a muddy ...