The original Park Tool DT-5 Disc Brake Mount Facing tool was rarely seen outside of the bike shop environment, and we expect the new DT-5.2 to follow suit, but with so many road, gravel, mountain and e-bikes featuring disc brakes, we have had more home mechanics requesting the facing tools. So what does this tool do? The DT-5.2 is engineered and built to accurately face front or rear disc brake mounts so they are precisely aligned to the rotor. The tool will face any IS Mount, Post Mount, or Shimano's Flat Mount standard (now used by most frame builders), including low clearance chainstay mounts.

Telescoping axle adaptors allow use with any configuration of open (QR) or thru-axle dropouts and dropout widths (including Boost 110, Boost 148 and all fat bike axles), making this the most versatile and complete disc mount facing tool on the market. It includes two facing cutters, one for IS Mounts, and the second for Post and Flat Mounts. These cutters work on steel, carbon, aluminum, and titanium mounts. All tool components should be kept clean and the cutter should be wiped with an oily cloth or rust inhibitor after use. Always store the DT-5.2 in its original packaging or in another safe location. The DT-5.2 ’s cutter should be periodically replaced or sharpened by a qualified technician. Park Tool offers a sharpening service that returns cutters to factory specifications.

While this tool can be practically and properly used by shop and home mechanics, every user should study and and follow the instructions for the exact tool set-up for each mount type and dropout design. This is a precision facing tool system that is designed to very specifically face mount surfaces to align perfectly with the dropouts- which ensures a straight rotor mounted properly on your hub will be in the absolute correct position. Please don't just "wing it". Always follow the instructions, which also feature detailed diagrams. As with any frame cutting tool, you can just as easily ruin a frame as make it perfect. Besides the tool sharpening service, Park offers replacements for every part of the the DT-5.2, a breakdown of which is included with the tool set, and can also be found on Park Tool's website. If you are a home mechanic with several disc brake bikes and feel confident in your abilities, the DT-5.2 Disc Brake Mount Facing Set may be well worth the investment as many bike shops charge over $100 to face disc mounts.