how to install mountain bike derailleur

How to Install a Mountain Bike Derailleur

Installing a mountain bike derailleur can seem daunting, especially for those who are new to bike maintenance. However, with the right tools, a little patience, and step-by-step guidance, you can successfully install or replace a derailleur on your mountain bike. This article will provide a comprehensive guide to help you through the process.

Tools and Materials Needed

Before you begin, gather the following tools and materials - A new derailleur (if replacing) - Hex wrenches (usually 4mm or 5mm) - Phillips screwdriver - Bike stand (optional, but helpful) - Chain tool (if you’re also replacing the chain) - Lubricant for the chain - Cleaning cloth

Step 1 Prepare Your Bike

First, ensure your bike is properly positioned for maintenance. If you have a bike stand, place your bike securely on it. If you don't have a stand, flip the bike upside down with the handlebars resting on the ground. This allows easier access to the derailleur.

Step 2 Remove the Old Derailleur

1. Shift to the Smallest Gear Shift your chain onto the smallest chainring and the smallest rear cog. This releases tension on the derailleur and makes it easier to remove.

2. Detach the Chain If you need to remove the chain to replace the derailleur, use the chain tool to break the chain link. If using a quick link, just separate it carefully.

3. Unscrew the Derailleur Using the appropriate hex wrench, unscrew the derailleur from the derailleur hanger. Some derailleurs may also require detaching the cable.

4. Remove the Cable If you haven't done so already, loosen the bolt holding the derailleur cable. Release the cable from the cable housing.

1. Attach the New Derailleur Position the new derailleur onto the derailleur hanger and secure it using the hex wrench. Make sure it's facing the correct direction—typically, the pulley wheels should align parallel to the derailleur hanger.

2. Reconnect the Cable Feed the shift cable through the cable housing and into the barrel adjuster of the derailleur. Tighten the bolt to secure the cable in place. Make sure the cable is taut but not overly tight, as this could affect shifting performance.

3. Reattach the Chain If you removed the chain, now is the time to reattach it. Feed the chain through the derailleur’s jockey wheels, ensuring it follows the correct path. Use the chain tool if necessary to reconnect the links.

Step 4 Adjust the Derailleur

Proper adjustment is crucial to ensure smooth shifting performance.

1. B-Tension Screw Start by adjusting the B-tension screw, which controls the distance between the derailleur’s pulley wheels and the cogs. This distance should be around 5-6mm.

2. Limit Screws Identify the high and low limit screws, usually marked with H and L. The high limit screw prevents the chain from shifting off the smallest cog, while the low limit screw does the same for the largest cog. Adjust these screws so that the derailleur doesn’t allow the chain to escape.

3. Cable Tension Finally, fine-tune the cable tension using the barrel adjuster. Shift through all gears to ensure smooth transitions. If the derailleur doesn’t shift adequately, you may need to adjust the cable tension slightly.

Step 5 Test Ride

After making adjustments, take your bike for a test ride to evaluate the shifting performance. If you encounter issues, return to the adjustments you made—sometimes a small tweak can make a significant difference.

Conclusion

Installing a mountain bike derailleur may require a bit of practice, but following these steps will guide you through the process. Regular maintenance of your derailleur is essential for optimal performance, so don’t hesitate to tackle this task. Remember, having the right tools and being patient are key elements in successfully replacing or installing a derailleur. Happy biking!