how to change derailleur on mountain bike

How to Change a Derailleur on a Mountain Bike

Changing a derailleur on a mountain bike might seem challenging, but with some basic tools and a little know-how, you can easily do it yourself. The derailleur is a vital component of your bike’s gear system, responsible for shifting the chain between gears. Whether you're upgrading to a better model or replacing a damaged unit, here's a step-by-step guide to help you through the process.

Tools You’ll Need

1. Screwdrivers Both Phillips and flat-head 2. Allen Wrenches Usually, a 5mm wrench will suffice 3. Chain Tool For removing and installing the chain 4. Bike Stand Optional but very useful for stability 5. Cloth or Waste Paper For cleaning

Step 1 Remove the Wheel

Start by removing the rear wheel from your bike. This makes access to the derailleur much easier. If you have a quick-release system, simply open the lever and pull the wheel out. If you’re using a thru-axle, be sure to unscrew it appropriately.

Step 2 Disconnect the Chain

Using the chain tool, disconnect the chain by removing a link or breaking it at a designated location. Make sure to record how the chain runs through the derailleur and around the sprockets to ensure everything is put back together correctly.

Step 3 Remove the Old Derailleur

Locate the mounting bolt that holds the derailleur to the derailleur hanger on the bike frame. Use the appropriate Allen wrench to remove the bolt. After that, you can detach the derailleur from the chain and gently pull it away from the hanger.

Take your new derailleur and attach it to the clutch or derailleur hanger. Align it so that it sits properly when the chain is threaded through it. Tighten the mounting bolt carefully, making sure not to over-tighten, as that can cause damage.

Step 5 Re-thread the Chain

Reinstall the chain, following the path you noted earlier. Ensure that the chain runs through the new derailleur correctly. For most derailleur models, there are marked locations for the chain to follow, so pay attention to these guides.

Step 6 Adjust the Derailleur

Before you reattach the wheel, it is a good time to adjust the derailleur. The adjustment screws (high and low limit screws) help set the range of movement of the derailleur so that it shifts smoothly between gears. With the bike back on the ground and manually rotating the pedal, shift through the gears to check if the chain moves smoothly.

Step 7 Test the Setup

Finally, reattach the rear wheel. Spin the pedals and shift through the gears, checking to ensure that the chain moves appropriately across the entire cassette. Pay attention to any unusual noises or skipping. If necessary, make further adjustments to the tension and limit screws to ensure that the derailleur aligns perfectly with the gears.

Conclusion

Changing a derailleur on your mountain bike can enhance your riding experience significantly. Regular maintenance and timely replacements are crucial for ensuring optimal performance. Always remember to keep tools handy and maintain your bike regularly to avoid unnecessary complications during your rides. Happy cycling!