If your gears started skipping or shifting poorly right after a fall, a bike being transported, or the derailleur getting knocked, the hanger is a likely suspect since it is designed as a sacrificial part that bends before your frame or derailleur takes the damage. This tool lets you confirm and quantify the bend rather than guessing, so you know whether adjustment, replacement, or simply re-indexing the gears will fix the issue.

This tool is built to work with virtually all derailleur-equipped bicycles, since it threads into the standard derailleur mounting hole and adjusts to suit wheel sizes ranging from mountain bike to road bike. As with any hanger tool, gently working the arm to reach the rim without forcing it is the key to getting an accurate reading regardless of frame or wheel size.

This is traditionally considered a shop-level tool because precise, gentle straightening takes some feel, but a careful home mechanic who takes their time and makes small adjustments can absolutely use it successfully. If your bike has been dropped or knocked around during travel, having this tool at home means you can check and correct hanger alignment yourself instead of paying for a shop visit every time.

With the tool's arm resting near the rim at several points around the wheel, you use the handle to apply firm, gradual pressure in the opposite direction of the bend, checking the gap to the rim after each small adjustment. Working in small increments and rechecking often prevents overcorrecting, since aluminium hangers can weaken or snap if bent back and forth too aggressively.

A mildly bent hanger can usually be straightened safely once or twice, but a hanger that is severely bent or has been straightened multiple times is more prone to fatigue and sudden failure, so replacement is the safer option in that case. Since hangers are inexpensive and frame-specific, it is worth keeping a spare on hand, and using this tool to check alignment right after fitting a new one.

Yes, this is a genuine tool sold through DoGoodCo, built with a sturdy arm and handle designed to apply controlled force without flexing or losing accuracy over repeated use. If your tool arrives damaged or defective, our support team will help arrange a replacement as per store policy.