Adjust the rear derailleur cable tension.
Put the chain into the smallest (hardest) cog and upshift once. Look down from above the cassette to see if the upper derailleur pulley lines up with the second cog. If it is closer to the wheel, turn the barrel adjuster—the black plastic piece the housing inserts into—clockwise. If the pulley is further from the wheel, turn the barrel adjuster counter-clockwise.
FILED UNDER: Beginner Essentials / Bike / Gear & Tech / Triathlete Buyer's Guide TAGS: Aaron Hersh / Bike tune up / Gear Advice / how to clean your bike / how to tune a bike / how-to-repairs / tech advice / Triathlon tech