How to Adjust Shimano Gears on a Mountain Bike: A Simple Guide
To adjust Shimano gears on a mountain bike, start by shifting the bike onto the middle chainring and the smallest rear sprocket. Turn the barrel adjuster on the rear derailleur until the chain is running quietly and smoothly on the smallest rear sprocket. Next, shift the bike onto the largest rear sprocket and adjust the High limit screw until the chain is running quietly and smoothly on that sprocket. Finally, shift the bike onto the largest chainring and adjust the Low limit screw until the chain runs quietly and smoothly on that sprocket. Test the gears by cycling through them and make minor adjustments if necessary.