How to Align a Rear Derailleur Hanger
Derailleur hangers are easily bent and can cause shifting problems.
Today we’ll learn how to straighten integrated derailleur hangers. Shifting problems caused by a bent derailleur hanger are quite common. This can happen if your bike is dropped, crashed or bumped, or if it was poorly aligned at the manufacturer. The result is poor shifting even after all other adjustments have been made.
For this job you’ll need a repair stand and a hanger alignment gauge like this one called the DAG-2.2 from Park Tool. When compared to bike shop labor charges, it will pay for itself after 3-4 uses. You’ll also need a 5mm hex key for the derailleur mounting bolt, and a string or small strap to hold the derailleur out of the way while you align the hanger.
It is important to make sure your rear wheel is true and properly mounted in the frame dropouts, as the alignment tool compares the derailleur hanger to the rim surface. See the tutorials titled How to Remove and Install Your Wheels and How to True a Wheel.
The first step is to shift the rear derailleur onto the smallest sprocket and then remove the rear derailleur by turning the mounting bolt all the way counter-clockwise. There is no need to remove the shift cable or chain. Then tie the derailleur up onto the frame to keep it out of the way. If you have a replaceable derailleur hanger, you’ll first want to make sure the bolts holding it in place are properly tightened so they don’t move.
Now thread the tool’s shaft all the way into the hanger threads by turning it carefully clockwise into where the derailleur was mounted. If it doesn’t thread in smoothly, the threads may be damaged and need to be chased with a tap. We’ll cover this in a future tutorial. Do not use the tool’s threads as a thread chaser.
We’ll be checking the alignment at four different places on the rim: the 9 o’clock and 3 o’clock for horizontal alignment, and the 12 o’clock and 6 o’clock for vertical alignment. When aligned correctly, the alignment tool’s indicator will be roughly the same distance from the rim at all four locations.
For horizontal alignment, move the alignment tool’s arm to the 9 o’clock position and rotate the wheel so the valve is at the same spot. Loosen the knob and slide the indicator so it contacts the outside edge of the rim, and then tighten the knob again to hold the indicator in place. Now rotate the tool arm and valve around to the 3 o’clock position and see where the indicator sits. If the tip of the indicator is within 4mm of the rim on this side then the horizontal alignment is ok. If the difference is more or less than 4mm, carefully pull or push the tool’s arm, using it as a lever to slightly bend the hanger in the right direction, and then re-check the alignment on both sides.
You may need to repeat this process a few times until the alignment is within range. It’s important not to bend the hanger too much with the alignment tool. It’s best to bend it a little bit and then have to bend it some more, rather than bending it too much and having to bend it back again.
For vertical alignment, keep the indicator in the same position and then check the 12 o’clock and 6 o’clock positions the same way we did for the horizontal alignment. Always remember to move the air valve along with the indicator and place the indicator at the outside edge of the rim.
Once the hanger is aligned and within 4mm both horizontally and vertically, unthread the alignment tool. Apply a little waterproof grease to the derailleur’s mounting bolts threads and begin threading it back in clockwise. Make sure the B-screw adjustment is sitting behind the derailleur hanger. Then tighten the derailleur to the specified torque, usually around 8-10 Newton Meters or 70-90 Inch Pounds.
- Park Tool DAG-2.2 Derailleur Hanger Alignment Gauge
- Park Tool AWS-1 3-Way Hex Wrench
- Park Tool AWS-10 Folding Hex Wrench Set
- Park Tool HXS-1.2 Hex Wrench Set
- Park Tool PCS-9 Repair Stand
- Park Tool PCS-4 Repair Stand
Discuss this topic in the Bicycle Repairs and Mechanics Forum
Handlebars are either too loose or too tightLatest post 56 mins ago
Hello, I've had my bike from teenage years in the garage with the wheels off for a few years now. Put it all together and instantly remembered why it was in storage. The handlebars either move without the wheel turning or the handlebars get REALLY hard to turn (with the wheel ofc). Its a matter of maybe a quarter turn on the top bolt from loose to tight, there's no inbetween. I think when I was y...Read more
Patching a tireLatest post 3 weeks ago
In the past I have had a lot of punctures. When they happened, I patched the tube, but the holes in the tire were so small, they did not need patching. After many more kilometers, rubber started coming away around two of the holes in the tire, exposing the chords. If I did not do anything, a rock could cut the chords, destroying the tire. I wanted to get more use out of the tire. I cut patches fr...Read more
Schwinn Meridian Drive Wheel Missing Feather KeyLatest post 4 weeks ago
Hi, So I bought a used Schwinn Meridian sight unseen online auction for $59 & drove 8 hours round trip to get it. It appears to be brand new actually. When I got it home, the next day I checked out my score. When I sat on it and pressed on the pedals, they moved but the bike did not. I inspected the bike and realized that whoever put this trike together, forgot to put what appears to be ...Read more
I fell off my bike and slightly damaged my hand brake, resulting in a weak front brakLatest post 1 month ago
I had a previous incident with my bike, and the front brake got bent. Now when I try to use the front brake, it is very weak (when I ride the bike and fully depress the front brake, the bike does not stop quickly). I tried to fine-tune the disk brake caliper (I did it many times before), and it looks good and tight, but the front brake. What could be the reasons for this?...Read more
Full Rebuild vs ServiceLatest post 1 month ago
Hi, I've had my Giant Defy for two years now and have done about 4000 miles on it. I keep it clean and generally only ride in dry or damp conditions (never pouring rain). Apart from a potentially stretched shifter cable (won't go in highest gear despite adjusting barrel adjuster and limit screws) the bike rides fine. I keep on top of basic maintenance, cleaning, checking for chain wear etc... an...Read more
Sloppy front deraullierLatest post 1 month ago
Hi there how do i tell if my front deraullieur needs to be replaced on my hybrid it has a ton of play back and forth....Read more
Cracked shimano DI2 front derailleurLatest post 2 months ago
Hi, I got a cracked shimano DI2 front derailleur (see picture attached). I try soldering it but no luck (probably don't have the right solder). Any suggestions on how to fix that please? Thanks 20230206_170038.jpg (Size: 47.7 KB / Downloads: 35) ...Read more
Calculating bottom bracket spindle widthLatest post 2 months ago
Hello, I’ve got an old set of square taper FSA tempo cranks (2x) that I want to swap from a single speed 120 OLD bike to a 1x10 135mm OLD one. Any tips on how to calculate the spindle width for correct chain line? I can’t find anything for that model on the manufacturers website, and i don’t think measuring the one on the single speed will work with the different chain line....Read more
Help with headset preloadLatest post 2 months ago
First time adjusting a headset and I'd like to get it right. Brand new giant reign with a carbon frame, that I do not want to damage I finally have the preload set to where there is no play but I'm concerned that it is to tight... Stage 1- obvious play/clunk Stage 2- no clunk, but if I lock up the brake and push and pull hard, I can feel some very slight movement Stage 3 - no play or movemen...Read more
8 Speed on 7 Speed Freehub BodyLatest post 2 months ago
Awhile back, I was able to hack a 7 speed freehub body and get an additional speed out of it by using a 9 speed cassette with the narrower spacing. Note that these older freehub bodies are 7 speed exclusive. They do not typically have the space to fit a larger cassette on them. To do this, I took a 9 Speed Dura Ace 11-23 cassette and I simply removed the final combination cog from the back, then...Read more
How often do you wash your bike?Latest post 2 months ago
Ciao. I know that some bike riders overexaggerate the 'cleaning part' and wash (or spray) their bikes at least once a week. I know, it's mandatory after a muddy trail ride. But I'm thinkging more about daily commuters. It gets dusty here and there, but how long is too long without a shower for a bike? For a bike that rides almost every day....Read more
What's Wrong With My Bike? Squeaking or Squealing Noises?Latest post 2 months ago
I made a video of what my bike is doing. Can someone please watch and help? https://youtu.be/NTu-831CuGM...Read more
How to lubricate my bike's D-lock?Latest post 2 months ago
Looking for advice. I have repeated problems with my D-lock sticking. I've used standard light bike oil which then leaks all over my hands when I handle the lock. I have some 3-in-one PTFE spray: would that be better?...Read more
Best way to thoroughly clean a chain?Latest post 3 months ago
Hi everyone! I hope you're enjoying a great start to 2023. I'm curious to hear your go-to method for getting a chain truly clean. I don't mean, just looks shiny or is good enough for a quick clean after a ride. I want to know what you do when you want to get every last morsel of ground-up, link-destroying, roller-eating, tooth-gnashing crud out of your chain. The Best Chain-Cleaning Recipe Ever?...Read more
700c Wheels on a 26er or 26" Bike FrameLatest post 3 months ago
Obviously, this doesn't speak for them all, but they certainly might fit! And not even just barely (as suggested by some sources), but with a lot of room to play with. This is another GT Tempest frame that I recently purchased. It's originally a 26" alloy touring bike. As you can see, there's lots of head room, and plenty of clearance to increase the tire size up to probably 38c—maybe even 40c....Read more