The derailleur hanger goes by many different names. Bike mechanics know them as mech hangers, rear mech hangers, gear hangers, dropout hangers, or simply bike hangers. The bike model and make determine the hanger design, so there are hundreds of thousands of different kinds out there.
No matter what you call it or what it looks like, its purpose remains the same: to protect your bike frame, drivetrain system and ultimately your derailleur, all of which are far more expensive to replace than a little hanger.
So do you need a derailleur hanger on your bike? Yes! Why not save yourself the trouble, headache, and drain on your wallet?
What Is a Derailleur Hanger?
For people who are newer to cycling and unfamiliar with all the mechanical components, the derailleur is part of the drivetrain system. Your drivetrain is a collection of parts that also include pedals, cranks, chainrings, a chain and cassette (or cogs). These pieces work together to mitigate your pedaling force and how it affects your speed.
The derailleur hanger is typically made from a soft alloy. It is the middle man between your bike frame and derailleur. It is secured to your bike frame via bolts, screws, or lock nuts/rings. It attaches to the derailleur with bolts.
Basically, the hanger attaches your derailleur to your frame.
What Does a Derailleur Hanger Do?
The derailleur hanger is the sacrificial lamb of your drivetrain system. Your rear derailleur is in charge of shifting your chain from one gear to the next. The derailleur hanger helps keep your chain aligned. If you damage your rear derailleur, you may no longer be able to smoothly shift gears. Designed to take the brunt of the force, derailleur hangers protect your rear derailleur from impacts.
When Do You Replace a Derailleur Hanger?
It doesn’t take much to send the derailleur hanger out of whack. Sometimes all it takes is a good nudge from the bike squeezed into the rack next to yours.
If your hanger looks bent from a crash or a fall, that’s a visual indicator that it’s time to replace it.
If your hanger is severely bent you’re likely to hear a ‘tinging’ sound. This is a big red flag and you should dismount your bike immediately. Don’t ignore this sound. The noise is a precursor to your derailleur getting ripped off or the de-spoking of your wheel.
Not only do you need a derailleur hanger, but for many cyclists it’s also worth carrying a spare one.
Whether you’re on a touring adventure, a weekend ride or just commuting to and from work, having a spare derailleur hanger can save you from being late or having to walk your bike.
Enthusiasts are particular about how each bike part affects their ride. The derailleur hanger should not be overlooked. It may be small but it makes a huge difference. Regularly inspect your derailleur hanger and ensure that it is not bent or interfering with other parts of the bike. Pick up an extra hanger to keep on hand. This little piece of metal can make or break your ride.
Image at top: © Glory Cycles | Creative Commons