how to replace derailleur on mountain bike

How to Replace a Derailleur on a Mountain Bike

Replacing the derailleur on your mountain bike can seem like a daunting task, especially if you are not mechanically inclined. However, with the right tools and a bit of patience, you can successfully complete this task and get back on the trails in no time. This guide will walk you through the steps to replace your derailleur, ensuring your gear shifting is as smooth as possible.

Tools You Will Need

Before you start, it’s essential to gather the necessary tools

1. Allen wrenches (typically 4mm or 5mm) 2. Screwdriver (flathead or Phillips, depending on your derailleur) 3. Chain tool (if your chain needs adjusting) 4. Gear cable and housing replacement (if needed) 5. Adjustable wrench or pliers (for the lock nut) 6. Bike stand (optional, but helpful)

Step 1 Prepare Your Bike

First, ensure your mountain bike is clean and stable. If you have a bike stand, place your bike in it for easy access. If you don’t have a stand, flip your bike upside down, but be mindful of your handlebars or sensitive components.

Step 2 Remove the Old Derailleur

1. Disconnect the Gear Cable Locate the cable clamp on your derailleur. Loosen the screw with your screwdriver or Allen wrench and detach the cable. Be sure to remember how it runs for reinstallation. 2. Remove the Chain If the chain is connected to the derailleur, you may need to unhook it from the derailleur or use a chain tool to break the chain. Ensure you keep any spacers, pins, or other small parts safely.

3. Unscrew the Derailleur The derailleur is typically attached to the derailleur hanger with a bolt. Use your Allen wrench to remove this bolt. If your derailleur is held by a nut, use an adjustable wrench to disconnect it.

1. Attach the New Derailleur Position the new derailleur onto the derailleur hanger and tighten the bolt securely. Make sure it's aligned properly; the jockey wheels should be directly beneath the chain.

2. Reconnect the Chain Weave the chain through the jockey wheels of the new derailleur, ensuring it follows the correct path. If you had to break the chain, reconnect it using a quick link or any necessary pins.

3. Attach the Gear Cable Thread the gear cable through the derailleur’s cable routing and tighten the cable clamp screw. Make sure the cable tension is appropriate, but you can fine-tune this later.

Step 4 Adjust the Derailleur

1. Set the High and Low Limits Using the limit screws on your derailleur, adjust the high and low gear settings. The high limit prevents the chain from moving off the smallest cog, while the low limit does the same for the largest cog.

2. Tune the Cable Tension Shift the bike into the highest gear (smallest cog) and check if the derailleur shifts smoothly. If it doesn’t, you may need to either tighten or loosen the cable tension by turning the barrel adjuster.

3. Test the Shifting Shift through all the gears under load (while riding) to ensure everything functions correctly. If the chain hesitates or skips, return to your adjustments until the shifts are effortless.

Step 5 Final Check and Cleanup

After ensuring that everything is functioning well, take a moment to check that all bolts are tightened and that there are no loose ends. Clean any excess grease or dirt around your components and enjoy your mountain biking adventure.

Conclusion

Replacing your derailleur might seem complicated, but breaking it down into manageable steps makes the process straightforward. Whether you're prepping for a trail ride or conducting routine maintenance, knowing how to replace a derailleur gives you confidence and ensures your bike operates smoothly. Happy biking!