There are a variety of different shifters available today but they all do pretty much the same thing: pulling a cable to move a derailleur in one direction and then releasing the cable to allow the derailleur spring to move it in the other direction.
Most bikes these days use index shifters that are mounted on the handlebars. Index shifters make a click each time a gear change is made, which prevents riders from missing a shift. They’re much easier to use than the traditional friction-type shifters, seen mostly on older bikes. Friction shifters are usually mounted on the down tube as two levers that the rider moves up or down to move the derailleurs. For someone not used to friction shifters, it can be a little unnerving to take your hand off the handlebars to make a shift.
Most shifters today, such as the one shown in Figure 14-15, do not require much maintenance and are not designed to be dissembled. In some cases, worn levers can be replaced, but if the internal mechanism of the shifter starts to wear out and the clicks become less distinct, it’s probably time to replace the levers.
The one thing you can do with shifters is give an occasional spray of a light lubrication into their internal parts. Operate the shifter a few times after the application, and wipe off any excess grease.
To adjust the position, loosen the clamp bolt if there is one, and move the shifters to a more comfortable position (as shown in Figure 14-16). If the shifters are on a road bike and are wrapped with tape, instead of removing the tape, you can loosen the clamp holding the handlebars and rotate the handlebars forward or backward slightly.
Adjusting the position of the gear shifters.
In this section, we tell you how to remove shifters on road bikes, with a focus on STI-style shifters, where the shifter is integrated into the brake lever. To remove the shifters follow these steps:
1. Unscrew or remove the handlebar end plugs and then remove the handlebar tape.
2. Locate the bolt that holds the shifter onto the handlebars.
The position varies on different types of shifters although in many cases you need to roll back the rubber hood to find it.
3. After pulling back the rubber hood and finding the bolt, use an Allen wrench to loosen the bolt without removing it.
This will loosen the bracket and allow you to slide the shifter off the handlebars.
4. Repeat steps 1 through 3 for the other shifter.
5. The final step in removing the shifters is to remove the brake (see Chapter 8) and shift lever cables (see “The derailleur cable,” earlier in this chapter).
To install shifters, follow these steps:
1. Slide the bracket that holds the shifter onto the end of the handlebar and move the shifter toward the top of the handlebar.
2. Place a ruler against the bottom of the shifter lever and align it with the curved part of the handlebars.
This is a good starting point. From here, you can raise them slightly higher for a more casual and comfortable riding position.
3. Repeat steps 1 and 2 for other shifter.
4. To make sure the shifters are level, set the ruler across the top of both and adjust their position as needed.
5. When you’ve found the proper position for the shifters, tighten the mounting bolts.
6. With the shifters in place, thread both the derailleur and brake cables through the shifters and continue the cable installation according to the instructions in this chapter for derailleur cables and Chapter 8 for brake cables.
7. Tape the handlebars according to the instructions in Chapter 15.