how to install rear derailleur mountain bike

How to Install a Rear Derailleur on a Mountain Bike

Installing a rear derailleur on your mountain bike can seem like a daunting task, especially if you’re not mechanically inclined. However, with the right tools and a little bit of patience, you can do it yourself and save time and money on repairs. This guide will walk you through the steps necessary to install a rear derailleur correctly.

Tools Needed

Before you begin, gather the following tools - A 5mm Allen wrench (or the appropriate size for your bike) - A Phillips screwdriver - A pair of needle-nose pliers (for adjusting the cable) - Cable cutters - A bike stand (optional, but helpful)

Step 1 Remove the Old Derailleur

If you are replacing an old derailleur, start by removing it. Use the 5mm Allen wrench to take off the bolt holding the derailleur to the rear derailleur hanger. Once the bolt is removed, gently pull the derailleur away from the hanger. Be cautious not to damage the hanger itself.

Additionally, you’ll need to detach the derailleur cable. Loosen the cable anchor screw with a Phillips screwdriver and slide the cable out. If you have a chain tensioner, remove it as well to prevent it from blocking your access to the derailleur.

Step 2 Prepare the New Derailleur

Before installing the new derailleur, make sure it’s compatible with your bike’s drivetrain. Most mountain bikes use a 1x or 2x system, so check the specifications. Once confirmed, take the derailleur and locate the mounting point where it attaches to the derailleur hanger.

Step 3 Install the New Derailleur

Align the new derailleur with the derailleur hanger and insert the bolt. Tighten it carefully with the Allen wrench, ensuring it is secure but not overly tight — you don’t want to strip the thread on the hanger.

Next, thread the derailleur cable through the anchor point on the derailleur. Make sure to pull the cable tight and adjust the anchor screw to secure the cable in place.

Step 4 Attach the Chain

The chain can be reattached at this point. If you’ve removed your chain, ensure that it’s routed correctly through the derailleur’s jockey wheels (the small wheels in the derailleur). The chain should go through the top jockey wheel first and then back down through the lower jockey wheel.

Once the chain is correctly positioned, check that it is not twisted or tangled. If needed, use your needle-nose pliers to help maneuver the chain into place.

Step 5 Adjust the Limit Screws

Now that the derailleur is installed, it’s time for adjustments. Limit screws control how far the derailleur can shift the chain. Use a screwdriver to adjust the high and low limit screws, labeled as H and L. The H screw sets the outer limit for the highest gear, while the L screw sets the inner limit for the lowest gear.

To properly adjust these limits, shift to the highest gear and ensure the derailleur shifts correctly without overshooting. Repeat for the lowest gear, making sure the chain does not fall off.

Step 6 Fine-Tune the Cable Tension

Once your limit screws are adjusted, you’ll need to fine-tune the cable tension. Shift through the gears to check how smoothly the chain moves. If the chain isn’t shifting smoothly, use the barrel adjuster on the derailleur or at the shifters to adjust the tension slightly until you achieve perfect shifts.

Step 7 Test Ride

Finally, it’s time for a test ride. Take your mountain bike for a short spin, shifting through all the gears. Listen for any unusual noises and ensure the bike shifts smoothly. If you notice any issues, return to your adjustments, tweaking the limit screws or cable tension as necessary.

Conclusion

Installing a rear derailleur may seem complicated, but by following these steps and taking your time, you can do it yourself. Not only will you enhance your bike maintenance skills, but you’ll also gain a greater understanding of your mountain bike’s mechanics, leading to a more enjoyable riding experience. Happy biking!