Shimano gears are highly sought after by bicycle enthusiasts because of their high-quality components. All bicycle gears need to be set when the bicycle is first assembled. Additionally, the gears will need to be reset every so often depending on how often you ride, and what type of riding you do.
For instance, if you ride on dirt trails with a lot of bumps and rocks, your gears will need to be set more often than if you ride a couple of times a week on paved roads. Setting gears is also called indexing.
Lift up the bicycle and place it on the bike stand. This will allow you to turn the pedals while setting the Shimano gears on the bike. If your bike is too heavy for you to lift alone, ask a friend to help you.
Find the gear mechanism attached to the back wheel of the bicycle. The device looks like a box with a small sprocket attached to it. There are also various cables running into the gear-changing mechanism.
Locate the thickest cable running into the gear mechanism box. This cable is the Shimano gear cable, and it should have an adjustable knob where you can adjust the gear indexing. You'll be using this knob to set the gears.
Put the bike into the highest gear using the gear changers on the handlebars. You'll know that the bicycle is in the highest gear because the chain of the bicycle will be on the smallest sprocket on the back wheel. You might need to turn the pedals a few times after you switch the gears on the handlebars to get the chain on the smallest sprocket.
Turn the knob on the gear cable from Step 3 to the right as far as it will go. This will give you a starting point for setting the gears.
Spin the pedals a few rounds with your hand until the back tire is spinning by itself.
Set the gear on the handlebars to the second highest setting. You won't see the chain change to the next sprocket on the back tire, because the gear knob isn't adjusted properly yet.
Twist the gear knob slowly to the left until you see the chain move to the second to smallest sprocket on the back wheel gear assembly. Stop twisting the knob.
Shimano gears can be set with minimal technical skills, so you don't have to bring your bike to a repair shop if the gears don't change smoothly.