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Park Tool Workshop Derailleur Hanger


The DAG-3 alignment gauge, lightweight and versatile, diagnoses and repairs bent or misaligned derailleur hangers. Its sliding indicator accommodates all bicycle rims and rotates for 360-degree measurement, while its long, precision-extruded aluminum body provides ample adjustment leverage.

Availability: 1 in stock

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EAN: 763477002631 SKU: WESPTDAG3 Categories: ,

Product Description

An alignment gauge, such as the DAG-3, is critical for identifying and rectifying bent or misaligned derailleur hangers, which are often the root cause of shifting issues. The DAG-3, with its innovative design, is designed to be lightweight, accurate, and adaptable. Its sliding indicator can assess derailleur hanger alignment against bicycle rims of all sizes, and it swivels aside to avoid seat stays, racks, and other obstructions, enabling comprehensive 360-degree measurements. The long, meticulously extruded aluminum body is constructed to precise standards and offers sufficient leverage for making adjustments.

Tech Specs

  • 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.)



Park Tool

In 1956, Hazel Park Radio and Bicycle Shop in St. Paul, Minnesota, primarily offered bike repairs using basic tools. Owners Howard Hawkins and Art Engstrom introduced a bicycle “repair stand” in 1963, which allowed easy access to bike parts. This stand gained popularity and led to the creation of more specialized tools as bikes became more complex.

By 1981, Howard and Art had sold their bike business to focus on Park Tool. The company expanded, offering over 500 products in 70 countries, and operates from a 100,000 square foot facility. Park Tool is now the preferred brand in the biking industry, not only for tools but also for repair tutorials and educational content.

Despite the evolving complexity of bikes, Park Tool’s mission remains unchanged: to create high-quality tools for both professional and amateur bike mechanics. The company attributes its success to its commitment to this mission, dedicated employees, and loyal customers. Park Tool is prepared to meet the challenges of bike maintenance in the future, just as it has for the past 60 years.