how to put a derailleur on a mountain bike

How to Put a Derailleur on a Mountain Bike

Installing a derailleur on your mountain bike can seem daunting if you're new to bike maintenance. However, with the right tools, a bit of patience, and a clear step-by-step guide, you can replace or install a derailleur with ease. This article will walk you through the process so you can ensure your bike's shifting is smooth and reliable.

Tools and Materials Needed

Before you begin, gather the necessary tools and materials

- New derailleur (ensure it's compatible with your bike) - Screwdriver (Philips or flathead, depending on your derailleur screws) - Allen keys (typically 4mm or 5mm) - Chain tool (if necessary) - Cable cutters - Bike grease (optional but recommended) - A clean cloth

Step-by-Step Guide

1. Remove the Old Derailleur (if applicable)

If you're replacing an old derailleur, start by removing it. Use the appropriate Allen key to unscrew the derailleur from the derailleur hanger on the bike frame. Next, disconnect the cable by loosening the cable anchor screw on the derailleur. If your derailleur is attached with a chain, use a chain tool to break the chain and remove it.

2. Prepare the New Derailleur

Once the old derailleur is removed, prepare your new derailleur. Check to ensure that it is the correct model for your bike’s drivetrain (either Shimano, SRAM, or another brand) and that it is compatible with your number of gears. Apply a small amount of bike grease to the threads of the mounting bolt, which can help with future removals.

3. Install the New Derailleur

Position the new derailleur onto the derailleur hanger. Align it carefully and secure it in place by tightening the mounting screw with the appropriate Allen key. Be sure not to overtighten, as this can strip the threads or damage the derailleur.

4. Reattach the Chain

If the derailleur requires you to put the chain back on, now is the time to do so. Carefully thread the chain around the jockey wheels of the derailleur, ensuring that it moves smoothly. If you're using a new chain, ensure it is the correct length. You can refer to the manufacturer's instructions for cutting and joining the chain if needed.

5. Attach the Shifting Cable

Feed the shifting cable through the cable housing and into the derailleur's cable anchor. Pull the cable taut and then tighten the anchor screw to secure it. Make sure the cable moves freely without any binding.

6. Fine-Tune the Derailleur Adjustments

Most derailleurs have limit screws that control how far the derailleur can shift in either direction. Adjust these screws to prevent the chain from derailing off the gears. You'll want to check the high and low limit screws to ensure they are properly set for the smallest and largest cogs on your cassette.

7. Test the Shifting

After adjusting the limit screws, test the bike’s shifting. Rotate the pedals and shift through all the gears to ensure the derailleur shifts smoothly and accurately. If it struggles to shift into certain gears, you may need to make additional adjustments to the tension of the cable using the barrel adjuster located on your shifter.

8. Final Checks

Once satisfied with the shifting performance, take your bike for a short test ride. Pay attention to any unusual noises or shifting issues, and make further adjustments if necessary.

Conclusion

Installing a derailleur on your mountain bike is a manageable task that can enhance your riding experience significantly. With the right tools and careful attention to detail, you can ensure that your bike will shift smoothly and deliver a more reliable performance on the trails. Don't hesitate to consult your bike’s manual or seek advice from a local bike shop if you encounter any difficulties. Happy cycling!