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 well-versed in bicycle mechanics. However, with the right tools and a little patience, it can be a rewarding process that enhances your bike's performance. In this guide, we'll walk you through the steps necessary to install a rear derailleur on a mountain bike, ensuring you enjoy a smooth and efficient ride.

What You’ll Need

Before getting started, make sure you have the following tools and parts on hand

1. New Rear Derailleur - Ensure it's compatible with your bike’s drivetrain. 2. Chain Tool - For adjusting the chain length if necessary. 3. Hex Wrenches - Usually a 5mm or 6mm, depending on your bike’s specifications. 4. Screwdrivers - A Phillips and a flat-head screwdriver may be useful. 5. Bike Stand - Optional, but recommended for ease of access and stability. 6. Clean Cloth - For wiping down components.

Step 1 Remove the Old Derailleur

If you're replacing an existing derailleur, start by removing it. Use a 5mm or 6mm hex wrench to undo the mounting bolt that secures the derailleur to the derailleur hanger. Be careful not to strip the bolt. Once it’s loose, gently slide the derailleur off.

Next, if the derailleur is connected to the chain, you might need to disconnect it. This can be done by removing the chain from the derailleur or, if applicable, using a quick link tool to detach it. Store the old derailleur and any hardware for potential future use.

Step 2 Install the New Derailleur

Take your new derailleur and begin by identifying the correct orientation. Most derailleurs have a specific way they need to hang—make sure the jockey wheels (the wheels that guide the chain) are positioned correctly. Install the derailleur by sliding it onto the derailleur hanger and tightening the mounting bolt securely. Be sure not to overtighten, as this could damage the hanger.

Now it’s time to reattach your chain to the new derailleur. If you had removed a section of the chain or disconnected it, make sure to set it back onto the derailleur correctly. The chain should pass through the jockey wheels, following the routing indicated by your derailleur's design. If necessary, use a chain tool to adjust the length of the chain.

If this is a new setup or a new chain, ensure the chain length is appropriate. A general guideline is that there should be enough slack in the chain to allow for proper shifting without the possibility of it falling off the derailleur.

Step 4 Adjust the Limit Screws

Most derailleurs come with limit screws that control how far the derailleur moves. There should be two screws one for the high limit (for the smallest cog) and one for the low limit (for the largest cog).

- High Limit Adjustment Shift to the smallest chainring and smallest cog. Adjust the high limit screw so that the derailleur is just barely aligned with the smallest cog. If it shifts past this point, it could derail the chain. - Low Limit Adjustment Shift to the largest chainring and largest cog. Adjust the low limit screw similarly, ensuring the derailleur does not shift excessively beyond the largest cog.

Step 5 Fine-Tune the Cable Tension

Install the cable by inserting it into the derailleur's cable anchor. Pull it tight and secure it using the cable anchor bolt. Shift through the gears to check how smoothly the derailleur responds. If it skips gears or hesitates, adjusting the barrel adjuster (often located on the shifter) can help refine the tension.

Step 6 Test Your Setup

Once everything is installed and adjusted, take your bike for a test ride. Shift through all the gears to ensure smooth transitions. Listen for any skipping or grinding noises and make further adjustments as needed.

Conclusion

Installing a rear derailleur on your mountain bike is a straightforward task that can greatly impact your ride quality. With practice, you'll become more adept at making adjustments and maintaining your bike. Not only will you improve your bike’s performance, but you’ll also gain a deeper understanding of how all the components work together. Happy riding!