How to Properly Adjust the Rear Derailleur on a Mountain Bike
To adjust the rear derailleur on a mountain bike, start by shifting into the highest gear and then loosen the barrel adjuster until the chain is lined up with the smallest cog. Next, shift into the lowest gear and adjust the high limit screw until the chain is lined up with the largest cog. Then, shift through the gears to ensure smooth shifting and make any final adjustments as needed by using the barrel adjuster. Test ride the bike to ensure the adjustments have been made correctly.