48. How to Align a Rear Derailleur Hanger
Derailleur hangers are easily bent and can cause shifting problems.
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.
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.
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.
I have just done a complete overhaul on my wife's mountain bike, here is a list of what I have replaced;
Shimano MF-TZ 31, 7 speed 14-34 mega range cog set.
Shimano FC-M 171, 48\38\28T Chain set.
Shimano RD-TX35 6\7 speed rear derailleur.
Shimano FD-TX51 front derailleur.
Shimano CN-HG40 Chain.
I have adjusted and indexed the rear mech. The problem I have is with the front mech, I can change from smallest to largest cogs OK but when I change from the largest it changes to the middle cog fine but will not go to the smallest cog no matter what... Read more >>
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Sanwa Road Bike. 10 Speed. Had for about 10 years. I only have one speed 5th gear. I know videos all over. I watch them and just can't get this thing correct. Thought I'd head here for help and I have a new Schwinn coming. That's pretty inexpensive also. Looks like a nice web site also.
Problem: Start with something simple. Getting from 5th to 10th. When I push the Front Derailleur by hand it snaps back. I can pull the lever on top of bike down to shift to 10th and the lever snaps back. If I put the bike in 10th the derailleur snaps back toward the bike causing the chain to go to ... Read more >>
I've recently bought a women's Schwinn Continental at a garage sale. We think it's a 1975, but we aren't sure. Anyway, I'd like to get a totally different rear (and possibly front) derailleur for it because no matter what we do, it doesn't like to switch into all of the gears. We read that the original derailleurs on the bike don't really work well with it, so we were looking at maybe a Suntour or Shimano, but we have no idea were to start or anything. Could some one give us some information that could help? Thanks in advance.... Read more >>
Hi all, I'm a bit new to the maintenance of a bike so would really appreciate any help. I have a road bike that needs a new rear derailleur fitted.
My current rear derailleur just says shimano on it but my gears are shimano sora triple deck. I've looked online for a replacement shimano sora derailleur which are all 9 speed but mine is an 8 speed. Will this cause a problem?
Also, I've seen that you need to know the total tooth capacity. Can you just confirm how you work this out?
Thanks for any help!... Read more >>
So today I ordered some new wheels for my 700c conversion. The wheels come with a 7 speed freewheel which is just what I need. However, my current cassette is 13/23 and the new one is 14/28. What adjustments will I need to make to the rear derailleur so that it will shift smoothly and accurately on the new cassette.
Jamin... Read more >>
I've encountered a very strange problem I've never had before. I have a Fischer mountain bike with shimano acera 8 gear derailer. About a week ago it suddenly developed a very strange problem, the derailer only travels part of the distance it should to give me the full gear range. Now I only get it to go to gear sprocket 2 at the low end through to sprocket 5 or 6 towards the high end.
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I'm a bike tech at dicks sporting goods in Bloomfield, MI and I'm having trouble with replacing the cables on an old 10 speed freestyle. I've only been working at this job for about 3 months now, so I don't have a ton of experience working on bikes yet, and I can't tell how to get the cable out of the shifter.
It looks like the cable should just be able to pop out of the end of the shifter (I have already removed the housing), but I can't get it to budge. Is there something else I need to do first before I can take the cable out, or is it just that this particular one is likely j... Read more >>
We just bought a hyper havoc within the last 2 months and have only ridden it a handful of times. My issue is the other night as we were riding along the chain snapped off. Looked like it broke? We just started riding again recently so we're not familiar with these new bikes at all. Do I need to buy a new chain or can this one be fixed? I snapped it back together but I just don't know if it'll last or what. Lol I apologize for my ignorance about anything mechanical lol.... Read more >>
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So I took my bike out for a ride and neither of the gears seem to shift, pressing the shift bottom (sorry dont know the name for it) next to the brakes doesnt do anything, no clicks or sounds, nothing happens.
I have no clue whats wrong with it so please help me, I'll upload more pictures if needed and do any tests
here are some pictures
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At age 43 I recently have taken up cycling, it's been about 20 years. I had found a 1982 Free Spirit 10 speed, Sears brand by Murray I think, at a junk store. $15 and everything seemed to work, couldn't pass it up. I put new tires on it and was riding, wheels fairly true, all 10 gears, no squaking or squealing, decent stopping. Then the other day, the left lever snapped off. No surprise being 32 year old plastic, I remember new bikes doing that in my younger days. So my question is, what's a good source to order this part from? I'd want to go metal and replace the whole assembly, I'm gues... Read more >>
I have a Trek 7000 (93/94) still with tons of original parts on her.
A few weeks ago, the rear shifter broke, not shifting to the lighter gears, but was still shifting to the heavier ones.
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Just like the one seen here:
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Hey folks - first off for full disclosure, I recently removed the RD from the hanger to get a look at the hanger. What I'm asking now seems to have happened after re-attaching the RD.
The bike is about a month old so I'm not considering worn out parts yet.
OK so the RD (Ultegra 6800) attaches to the hanger by one bolt. The RD pivots on that bolt. When at rest I can rotate the RD clockwise quite a bit. Just a little rotation counter clockwise. If I rotate clockwise and then let it go there is obviously a spring inside that pushes the RD back to a resting position.
Read more >>
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I've tried setting this up myself about 4 times using this guide
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