Wheel 1 on 1

How to Build a Road Bike #9 Aligning Your Rear Derailleur

 
This is Step 9 of a multi-part series on how to build a road bike.  There is a free eBook available that gives you instant access to the following:
  1. A FREE 43 page Full Color eBook – Available in PDF and iBook Format (iPhone/iPad)
  2. 15 FREE HD Step by Step Videos
  3. 110 FREE Full Color Pictures
NOTE*  All Park Tool pictures are courtesy of Park Tool.  Thank you Park Tool!
 
To download the free eBook and videos, please visit www.flocycling.com/buildabike.php and enter your email address.
 
To see Step 1, Installing your Bottom Bracket, click here.
To see Step 2, Installing your Crankset and Pedals, click here.
To see Step 3, Installing your Fork, Stem, and Handlebar, click here.
To see Step 4, Hanging your Derailleurs, click here.
To see Step 5, Installing your Saddle, click here.
To see Step 6, Installing your Shifters, click here.
To see Step 7, Installing your Cassette and Wheels, click here.
To see Step 8, Mounting your Brakes, click here.
Step 9 – Aligning Your Rear Derailleur

What You Need

Tools: 
  • Screw Driver (SD-SET)
Tools
 
Before You Get Started
  • Be sure that your rear derailleur hanger is straight before tuning your rear derailleur.  The rear derailleur hanger can easily get bent out of shape if the bike falls over.  If your derailleur hanger is not straight, take it to your local bike shop to have it fixed. 
  • There is an accompanying video available here.
Installation
 
1.  Align the center of your upper guide pulley teeth with the outside edge of the teeth of your smallest gear on your cassette using the Hi limit adjustment screw (see Figure 1).  Be sure to watch the video for additional information.
Figure 1
 
2.  Push the rear derailleur towards the frame and align the center of your upper guide pulley teeth with the center of the teeth of the largest gear on your cassette using the Lo limit adjustment screw (see Figure 2). Be sure to watch the video for additional information.
Figure 2
 
3.  Set the chain gap using the B-Adjust screw.  You will want approximately 6mm between the bottom of the gears of your cassette and the top of the upper guide pulley teeth throughout the entire arc of the rear derailleur (see Figure 3). Be sure to watch the video for additional information.
Figure 3
 
4.  You have now successfully aligned your rear derailleur.
This completes aligning your rear derailleur.


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Jon Thornham