48. How to Align a Rear Derailleur Hanger

Derailleur hangers are easily bent and can cause shifting problems.

IMPORTANT: Nuts and bolts on your bike should always be tightened to the manufacturer's specifications.
How to Align a Rear Derailleur Hanger
DVD Vol. 2 DVD Volume 2
This video is available on DVD

50% of the cost of the bicycle featured in this video was donated by JensonUSA.

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.

Tools

For this job you’ll need a repair stand and a hanger alignment gauge like this one called the DAG-2 from Park Tool. It costs about $50 dollars. 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.

Tool Installation

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.

Horizontal Alignment

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.

Vertical Alignment

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.

Tags

Related Links

Discuss this topic in the Derailleur Forums

02/16 Frayed derailleur cable end

The metal cap at the end of my derailleur cable somehow came loose so now the cable end has unravelled into multiple strands. They are a cut hazard and look ugly. Appreciate any suggestions on how to fix.... Read more >>

02/15 Since overhaul (I'm Impressed)

It's presently 0 Degrees F, with a -16 wind chill in Chicagoland...

It's been ~3 months since the overhaul of the 2 bikes, and I've been alternating them from the repair stand (Bunji Straps hanging from ceiling joist in basement)..
When I started I figured a squirt of oil was all that was needed.  I had no idea what nice bikes I had! 
I learned about strange part sizes from Here & Internet.
I learned about parts & "Alternate Parts" procurement from LBS, Here, & Internet.
I learned about loose bearings from the first dis-assembly.. and found b... Read more >>

02/12 Deore LX Derailleurs?

I have two Deore LX derailleurs... one is a RD550 and the other is a RD565.
Which one is a better derailleur or is there a better one?? Any differences between the two other than the model number?? Both have the SGS long cage.
Trying to figure out the Shimano numbers and quality grades.
Thanks... Read more >>

02/08 SRAM X9 - Rear Derailleur Pulley - Wobbles

Hello,

I have a Boarman Hybrid Pro (2010 Model - White http://road.cc/content/review/4160-boardman-urban-pro-ltd) and the I have had a lot of repairs on it recently.

After the latest repair I noticed the chain was wobbling from left to right more than what I expected. I bought it back to the bike shop but they gave me lip service on the cause and the repair for the problem.

With further inspecition I noticed that that both rear derailleur pulleys are wobbling and are l... Read more >>

01/26 Need to replace a RD-TZ30 drlr

Hi, I need to replace and old broken RD-TZ30 drlr 7 speed.

Does anyone know if the Shimano Acera M360 7-8 Speed would be an ok replacement?

It is for an old (but much loved) Schwinn Jaguar beach cruiser.

Thanks!... Read more >>

01/02 Rear derailleur help

I took off my rear derailleur to clean my bike and i need help putting it back on. Its a shimano derailleur with the hook. And i have a diamondback mountian bike. If anyone can help it would be appreciated!! I dont remember exactly how it was attached to the frame

Thanx
Jay... Read more >>

01/01 How to determine replacement XT/XTR derailleur?

I have an early 90's Merlin MTB frame with 90's era Shimano xt and xtr on it. I now use the bike primarily as a pavement hill climber (I live in a hilly residential area) with maybe 20% off road. Recently, the front derailleur stopped returning when released by the shifter. The derailleur shifts to a larger chain ring perfectly. When shifting to a smaller chain ring, the shifter appears to release the cable correctly, but the derailleur is not returning, despite obvious slack in the cable. I have to kick it over with my heel. Lubricating the various pivot points did nothing. I assume the... Read more >>

12/30 Chain skipping one gear while shifting

I purchased a 18 speed bicycle with shimano gears having revo shifters yesterday.
Today I noticed that while shifting from 2nd gear to the third gear it skips the third cog at the back and jumps to the fourth. There is no issue with other gears.
I would like to know why has this happened and at the same time what can be done inorder to fix this problem.. Kindly reply.. Smile... Read more >>

12/30 Brifters for old Deore XT 7 speed dérailleur

I've got an old high end Giant mountain bike I'm wanting to convert to a gravel bike, mainly changing the MTB bars to CX/road bars with integrated brake levers/shifters. Any recommendations for some road shifters/levers that would work with the Deore XT 7 speed / triple front derailleurs and cantilever brakes? Don't want to spend a lot, so replacing lots of other components isn't an option.

Thanks for any help you have.... Read more >>

12/14 [Rear Derailleur] Gears up/down by one cog

I don't exactly know how it happened. I've been trying to fix it for days but nothing works.

So let's say you had a 1-9spd derailleur:
If we would want to shift to the biggest cog we would go to the 1st gear, and if we would want to shift to the smallest cog we would go the the 9th gear. BUT that's not the case in my rear derailleur. I could only go to the 2nd smallest cog, and if I would want to shift to the biggest could I would only have to shift 8 times, this means that I would have 1 more shif... Read more >>

12/11 Back bike wheel does not catch gear

i dont know whats really going on but when i was riding my $300 swiss mountain bike i took a brake then got on and tried to peddle. it spawn around w/o catching the back tire. i checked to see if the chain was on, it was. i was having very slow reaction with the front gears with alot of noise before this. i have not used this bike no more then 4-6 times.

if anyone can help thanks. if i can repair it my self i would rather do that since i dont have cash for a repair person..

(but i did notice it started to catch when i go down the drive way (going somewhat speed... Read more >>

12/10 Shifting between first and second

I'm a real novice at this so please make allowances! I was having trouble (front derailleur) shifting up from first to second. When I flicked the shift lever into 2nd, the cage would move across seemingly correctly, but the chain would struggle, make a lot of noise and refuse to shift up. If I pushed the shift lever over a little more - towards 3rd - and held it for a couple of seconds, the chain would move up on to 2nd position and stay there OK. I tried to correct this by increasing the tension a little on the shift wire. The result of that was that it shifts up to 2nd correctly, but wo... Read more >>

11/22 Converting from downtube to Stem shifters?

I'm re-bearing, lubing, and overhauling my wife's 1969-70 Gitane Grand Sport Mixte, and I'm showing here the 'status' of the re-build... Expenses so far: ! $40.00 if I split the cost of tools in half!

Overall she's happy with the improvements in bearings and lube, and she's 'buying' the improvements in the braking system that hasn't arrived yet... but..
.

As only a wife can do... She says: "You know, I like the location: (Stem Shifters) of what you have on 'YOUR BIKE', and wish I had the same on: "My Bike"...... I have to reach too far to change gears..... Read more >>

11/18 18 speed right-shifter pod

Looking the bike over for needed parts, this one is the most obvious...right (rear) shifter pod's indicator lens is gone. It's an older 18 speed Gary Fisher Tassajara with Shimano Deore shift components...dual lever (rapid fire?).

Left pod is numbered 3 2 1 from left to right. Any suggestions on what to look for as a replacement? Plan on replacing both cables, etc. while I'm at it.

Thanks in advance!... Read more >>

11/13 Changing from 10s to 11s

Hi I have a Orbea Onix T105 Road Bike which is 10 speed but would like 11 speed, is it a nightmare to do or do i just buy 11 speed cassette and switch it over ?... Read more >>

New Thread
How to Align a Rear Derailleur Hanger
Repair Guide / Help Forums

Free Email Updates: