With heavy rain outside preventing a ride, it's the perfect time for cyclists to stay indoors or visit a bike shop to upgrade their beloved machines. This short video takes you to the scene of a road bike drivetrain upgrade, with close-up shots of removing and installing the bottom bracket bearings and the large rear derailleur pulleys, swapping in top-tier CeramicSpeed ceramic bearings and the oversized pulley wheel system (OSPW). The footage closely showcases the ultra-low-friction ceramic balls spinning freely and almost without resistance when lightly flicked, along with detailed shots of the exquisite craftsmanship of the metal and carbon fiber pulley cage. This passion for indoor upgrades on a rainy day when outdoor riding isn't possible—how tempting is the pedaling smoothness and free-spin feedback once installed?