Mountain bike gear adjusters come in two types: barrel adjusters and top-drop adjusters. The majority of production mountain bikes have a hand-operated barrel adjuster at the rear derailleur. Top-drop adjusters attach at the top of a derailleur and adjustments are made with a metric wrench. Installing gear adjusters is not complicated. A new shift cable ensures gear adjusters can be set to regulate the movements of the rear derailleur effectively when you change gears.
Step 1
Slide the gear adjuster onto one end of the stranded shift cable. Slide a barrel adjuster on so the barrel is closest to the end of the cable. Slide a top-drop adjuster on so the threaded fitting is closest to the end of the cable.
Step 2
Insert the end of the stranded cable into the cable port on the back or top of the rear derailleur and push it into the cable stop. Tighten the cable fixing bolt with a 5-mm Allen key. Allow a barrel adjuster to rest against the outer end of the derailleur. Screw a top-drop adjuster fitting into the top of the derailleur and partially tighten the adjuster with a 10-mm open-end wrench.
Step 3
Apply a thin coating of lightweight oil or cable lubricant on the stranded cable. Slide the cable housing onto the free end of the shift cable and push it into the cable cap on a barrel adjuster. Push the end of the housing into a top-drop adjuster.
Step 4
Feed the free end of the cable and housing through the cable guides on the bike frame, starting at the guide closest to the derailleur. Drape the cable over the handlebars near the rear derailleur shift lever.
Step 5
Take a position near the rear derailleur. Grip the cable housing firmly with one hand and pull the cable toward the derailleur, making a uniform bend that has a straight section at the adjuster. This ensures the cable operates freely and efficiently.
Step 6
Move to the handlebars. Manipulate the shift cable, as necessary, to make a uniform bend with a short straight section at the shift lever.
Step 7
Pull the weather boot away from the rear derailleur shift lever to expose the cable stop connection. Grip the shift cable with your thumb and forefinger at the point where it intersects with the cable stop.
Step 8
Attach cable cutters on the cable next to your thumb and forefinger. Move your fingers 1/2 inch from the jaws of the cutters. Squeeze the handles of the cutters quickly and deliberately, making a clean cut through the housing and stranded cable. Discard the remaining portion of the cable and housing.
Step 9
Position the end of the cable at the cable stop on the shift lever. Use your thumb and forefinger to mark the point on the cable at the outer end of the shift lever adjuster. Carefully cut the cable housing at this point with the cutters, making sure not to cut into the stranded cable.
Step 10
Insert the stranded end of the cable into the outer end of the adjuster and into the cable stop. Push the end of the cable housing firmly against the adjuster and tighten the fixing bolt with the 5-mm Allen key.
Tips and Warnings
- Refer to the your mountain bike manufacturer's website for gear adjustment procedures and specifications. Refer to a mountain bike technical website, such as ABC-of-Mountain-Biking, for instructions on tuning gearshift systems. Tune the system before riding the bike.
Things You'll Need
- Gear adjuster, by type of derailleur
- Shift cable and housing
- 5-mm Allen key
- 10-mm open-end wrench
- Lightweight oil
- Cable cutters
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