How to use hanger alignment tool?
To use a derailleur hanger alignment tool, such as the DAG-2.2 mentioned in the reference, the general process involves attaching the tool to the hanger, using its arm to measure the distance to the wheel's rim, and carefully bending the hanger until the distance is consistent around the entire rim.
Aligning a bent derailleur hanger is crucial for proper shifting performance. A misaligned hanger can lead to noisy shifting, poor gear selection, or even derailment. The alignment tool helps you identify exactly where the hanger is bent and provides leverage to gently bend it back into place.
Here's a breakdown of how to use a hanger alignment tool:
Understanding the Tool
A derailleur hanger alignment tool typically consists of a threaded end that screws into the hanger threads and a long arm with a gauge or indicator at the end. This arm pivots and extends, allowing you to position the indicator near the wheel's rim.
Step-by-Step Alignment Process
Using the reference as a guide, the process involves bending and measuring distance to the rim to achieve a specific tolerance.
- Prepare Your Bike: Shift your derailleur to the smallest cog. It's often easier to remove the derailleur entirely, leaving just the hanger. Ensure your wheel is securely installed in the dropouts and properly inflated.
- Attach the Tool: Screw the threaded end of the alignment tool firmly into the derailleur hanger threads. Make sure it's snug but do not overtighten, as this could damage the hanger.
- Position the Indicator: Extend the tool's arm and position the indicator or gauge close to the edge of the wheel's rim. Choose a starting point, typically near the valve stem or a spoke for reference, often the 6 o'clock position.
- Measure Initial Deviation: Rotate the wheel slowly while keeping the tool arm stationary. Observe the distance between the indicator and the rim at different points around the wheel (e.g., 6, 9, 12, and 3 o'clock positions). Note the largest and smallest distances. A significant variation indicates a bent hanger.
- Reference insight: The goal is to reduce the distance variation.
- Identify the Bend: The hanger is bent towards the rim where the gap is smallest and away from the rim where the gap is largest.
- Bend the Hanger: Use the alignment tool as a leverage bar. Gently bend the hanger in the required direction. If the indicator was too close at the 6 o'clock position, for instance, you would bend the hanger away from the rim at that point using the tool. Make small adjustments!
- Reference insight: "So we bend and we measure our distance to the rim." This highlights the core iterative process.
- Re-Measure: After bending, rotate the tool arm back to your initial measurement points (6, 9, 12, 3 o'clock) and measure the distance to the rim again.
- Achieve Tolerance: Repeat the bend-and-measure process until the distance between the indicator and the rim is consistent at all measured points.
- Reference insight: "Now the gap is less than three millimeters." This indicates a typical target tolerance. You want the variation in distance at all points to be less than this value, often cited as 3mm or 4mm depending on the tool or guide. Ensure the absolute distance is consistent, meaning the difference between the max and min gap is within the tolerance.
- Check Perpendicular Axis: The reference mentions, "So remove to check the perpendicular axis." This likely refers to checking alignment not just horizontally (side-to-side relative to the wheel) but also vertically or axially. While the primary check is usually side-to-side, ensuring the hanger face is square is also important. Some tools have features for this, or it might involve a visual check or a specific measurement procedure depending on the tool model.
- Final Check: Once satisfied with the alignment at all points and axes, remove the tool. Re-install the derailleur if you removed it. Test shifting through all gears to ensure smooth operation.
Key Considerations
- Patience: Hanger alignment is a precise process. Make small bends and re-measure frequently. Over-bending can weaken or break the hanger.
- Wheel Security: Ensure the wheel is seated correctly and securely tightened in the frame.
- Tool Specifics: While the general principle is the same, specific tools might have slightly different procedures or measurement indicators. Always refer to your tool's instructions if available.
By following these steps, you can effectively use a hanger alignment tool to correct a bent hanger, restoring crisp and reliable shifting to your bicycle.
