Power was the single metric I was looking to improve during the lead-up to La Ruta. I became power savvy by establishing my baseline watts at lactate threshold and VO2 Max during the F.U.E.L. testing we covered in Part II and then had the next six months to train against these numbers to improve fitness and manage nutrition on long rides. Yet I still had just one gap in my arsenal of gear: a power meter for my mountain bike. The Stages Power X9 ($700) is both new and affordable relative to other power meters, so I decided to give it a test run.