The Park Tool DAG-3 Derailleur Hanger Alignment Gauge, click to enlarge
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Item # DAG-3

/ Tools / Derailleurs & Shifting / Frame & Fork

Derailleur Hanger Alignment Gauge

An alignment gauge is essential for diagnosing and repairing bent or misaligned derailleur hangers, often the source of shifting problems. The DAG-3 features an all-new design, engineered and built to be light, accurate and versatile. The sliding indicator can measure derailleur hanger alignment against bicycle rims of any size, and rotates out of the way to clear seat stays, racks, and other obstacles, allowing 360 degree measurement. The long, precision-extruded aluminum body is built to exacting tolerances and provides ample leverage for making adjustments.

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DAG-3 Features

  • Compatible with 16" to 29"+ wheels (ISO/ETRTO rim sizes from 317 to 630+)
  • Replaceable M10 threaded tip
  • Fits low-clearance thru-axle derailleur hangers and Shimano® Direct Mount hangers
  • Length: 420 mm (16.5")
  • Weight: 645 g (22.75 oz.)



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Replacement Parts

DAG-3 Derailleur Hanger Alignment Gauge