After months of continuous use, mountain bike gear changers, more commonly called "shifters," may need to be serviced. This is particularly true for mountain bikes used in muddy or dusty conditions. The actual shifts may not be as crisp and clean as you remember, or shifters may not work at all. This is commonly a result of contamination from dirt inside the cable housing and/or shifter body itself. The problem can be easily fixed with a proper solvent and application of grease in the right area. The following instructions concern the common mountain bike twist-grip shifter design.

Instructions

Things You'll Need:
WD-40
Plastic friendly cleaner/degreaser
Needle nose pliers
Set of Allen wrenches
Rag
Cotton swabs
Shift cable and housing

Step 1Shift onto your smallest chain ring or cog. Loosen the anchor bolt securing the shift cable to the derailleur. This bolt will likely be an Allen bolt. Remove the crimp-end cap from the cable. Pull the cable free of the derailleur.

Step 2Pop the cable hatch open on the shifter. Remove the Allen head screw or plastic clip holding the cable head in place. Pull the cable free of the shifter.

Step 3Clean the cable and cable housing. Wipe the cable free of any grease and grime. Spray a solvent such as WD-40 into the cable housing.

Shifter body
Step 1Slide the stationary grip off the handlebar and loosen the clamp bolt retaining the shifter body to the bar. Pull the shifter free of the bar.

Step 2Separate the twist-grip from the shifter body, pinching the retaining clips with a pair of needle nose pliers. Slide the twist-grip free.

Step 3Clean the individual parts, using a plastic friendly cleaner/degreaser. A cotton swab is ideal for this procedure.

Step 4Apply a bead of grease to all contact points within the shifter. Critical points include where the twist-grip contacts the sleeve and where the cable rides over the grooves.