Bicycles/Maintenance and Repair/Tools and Supplies/Headset Wrench

Similar to a cone wrench, a headset wrench is a thinner than usual open ended wrench and is used to adjust the cone or cup and locknut in a threaded headset. Common sizes range from 30mm to 36mm. In general two headset wrenches are used in parallel to tighten the locknut against the cup or cone.