PARK TOOL DAG-2.2 Bicycle tool

The PARK TOOL DAG-2.2 Bicycle tool is a specialist shop tool designed to measure and correct misaligned derailleur hangers, addressing a large share of bicycle shifting issues. Constructed with a heavy-gauge, chrome-plated steel gauge bar and an upgraded inner shaft, the tool combines stiffness and measuring accuracy to check hanger alignment across a wide range of wheel sizes. Its adjustable design fits 20" to 29"+ wheels and includes a replaceable threaded tip to maintain long-term serviceability.

Advantages

The DAG-2.2 provides precise alignment checks thanks to tighter manufacturing tolerances and an improved shaft for added strength. Improved clearance and reach allow the gauge to access more frame and hanger combinations, including low-clearance thru-axle derailleur hangers and Shimano® Direct Mount designs. The chrome-plated gauge bar resists corrosion while the replaceable tip extends the tool's usable life, making it suited for professional workshop use.

Suitable for

• Measuring and straightening misaligned derailleur hangers on bicycles
• Workshop diagnostics for shifting problems
• Service and maintenance of road, gravel, mountain and e-bikes equipped with derailleurs
• Compatibility checks for frames and aftermarket hangers

Key specifications

• Material: heavy-gauge chrome-plated steel gauge bar with robust inner shaft
• Wheel compatibility: adjustable to fit 20" to 29"+ wheels
• Length: 16 inches (41 cm)
• Replaceable threaded tip for sustained accuracy and serviceability
• Design: improved clearance and reach for low-clearance thru-axle hangers and direct-mount configurations
• Color: black and grey
• Quantity per pack: 1 piece

How to use

Mount the bicycle securely in a workstand and remove the rear wheel if needed for access. Adjust the DAG-2.2 to the correct wheel radius (20"–29"+) and position the gauge bar so the replaceable tip contacts the derailleur hanger. Rotate the gauge around the hub axis to observe any deviation between the gauge and the hanger face. To correct misalignment, apply controlled pressure or use the tool's levering capability to bend the hanger back toward true, re-checking alignment frequently until the hanger is straight within acceptable tolerance. Reinstall components and verify shifting performance under pedal load.

Usage recommendations

Use the DAG-2.2 on a securely supported bicycle and work incrementally when bending hangers to avoid over-correction. Regularly inspect and replace the threaded tip if worn to maintain accurate measurements. For severe bends or cracked hangers, replace the hanger rather than attempting repair. Keep the gauge clean and lightly lubricated at moving parts to preserve tolerance and prevent corrosion.