What is the Park Tool DCW-4 Cone Wrench used for?

The Park Tool DCW-4 Double-Ended Cone Wrench is a 13mm and 15mm thin wrench designed for adjusting cup-and-cone wheel hub bearings. Cone wrenches need to be thin enough to fit into the narrow gap between the cone and the locknut on a threaded hub axle, and the DCW-4 is manufactured from thin heat-treated steel to fit precisely where standard wrenches cannot. Made from nickel-plated heat-treated steel for durability, it fits 13mm and 15mm cones found across a wide range of road and mountain bike hubs.

Cup-and-cone hubs still appear on a large portion of bikes in regular use, from entry-level road bikes to classic steel frames and commuters. The small tool size also makes the DCW-4 easy to carry in a kit for roadside hub adjustments. If your bike has Shimano or other threaded cup-and-cone hubs, a cone wrench is a required tool for any hub service.