BENT Derailleur Hanger Fix: Gravel Bike, Road Bike, MTB, Any Bike

fix a bent derailleur hanger
Ruh Roh! This hanger is bent.

Putting it mildly, a bent / misaligned derailleur hanger is among the leading causes of poor shifting with one’s rear derailleur. A visual inspection may indicate the derailleur to be in good working order, but without the hanger being straight, shifting will be compromised no matter how much tinkering you do. This issue can be a problem for all drivetrains with rear derailleurs no matter the type of derailleur, or type of bicycle. In the experience of JOM, this issue has even plagued review bicycles, brand new out of the box (barring shipping damage).

Let’s Align a Derailleur Hanger Video

Alternative Video Link for those reading via email subscription.

fix a bent derailleur hanger on a gravel bike
Shifting is severely compromised

There are several derailleur hanger alignment tools available to perform the realignment, but we prefer the best and last you’ll ever need, the Abbey Bike Tools HAG (Hanger Alignment Gauge).

fix a bent derailleur hanger on a gravel bike
This derailleur hanger is a wee bit bent.

Here’s a blurb about the tool that we purchased from Abbey Bike Tools: “The derailleur hanger is the foundation for the modern drive train to work properly. With modern bikes getting as many as 13 cogs in the space that we use to put 8 it’s never been more important to make sure the hanger is perfectly straight. Sadly many of the current tools just aren’t capable of achieving this kind of precision.”

fix a bent derailleur hanger on a gravel bike

“We went through extra steps to make this tool half precision measuring instrument and half pry bar.”

fix a bent derailleur hanger on a gravel bike
Thread your hanger alignment tool of choice

Other Features

  • Tolerances as tight as a quarter of a thousandth of an inch (.0063mm) in some critical dimensions of this tool.
  • Ability to lock in the feeler so you don’t have to second guess your measurement after bumping it on the tire.
  • Top half of tool will rotate out of the way of fender stays and frame tubes.
fix a bent derailleur hanger on a gravel bike
Closing the gap to the rear rim
fix a bent derailleur hanger
Gap closed, looking good
fix a bent derailleur hanger
Near perfect shifting

Learn more about Abbey Bike Tools, and check out our factory tour video of Abbey Bike Tools!

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1 Comment

  1. The Abbey tool is awesome, but if you don’t have the money:
    A poor man’s derailleur alignment tool is any old 10mm x 1mm rear axle, the longer the better. You can use an axle nut or cone to lock it in place, and a cheater bar if necessary for leverage. You can get the alignment surprisingly close by eyeing the hub axle from top and back, and bending the hanger to make it all parallel.

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