Derailleur Hanger Too Long? Replace?
08-19-09, 09:03 PM
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Derailleur Hanger Too Long? Replace?
Sigh............
So I built a bike for a friend. The frame is an old Kobe "Cobra". The cranks on the bike were 7 speed, with a six speed free wheel and an old Suntour Derailleur.
I converted the drive train to a seven speed with a a cheap Shimano "Altus" rear deraileur. I kept the original Altus Front Derailleur that came with the frame. I put on Salsa seven speed chain rings.
When I installed the drive train I had shifting problems. I noticed that the frame was slightly bent and the dropouts were bent and mis-aligned. I corrected those problems but continued to have shifting problems.
This is where my troubles began.
I tried every bit of troubleshooting I know of, from the Barnett's manual to Sutherlands, etc. But I could not get the shifting right.
I believe the problem was staring me in the face the whole time. When I put on another derailleur to check to make sure it just wasn't a shot derailleur, I noticed the derailleur hanger seemed a bit long. This seemed to make sense with some of the symptoms I observed.
I measured the distance from the dropout flat to the top edge of the derailleur mounting hole and compared them to mine and other bikes in my building, and sure enough, the hanger is a good 7mm longer than other derailleur hangers.
I called a couple local shops and they basically said "Huh? You're crazy!"
A passage in the Paterek frame builders manual says that cutting these hangers off and brazing on new ones are an easy and reasonable fix for bent and torn derailleur hangers.
Called local shops again with this idea and they said "Huh? You're crazy!"
So I',m thinking, just replace the derailleur hanger with a new one?
Has anyone heard of abnormally long derailleur hangers like this?
I'm thinking it's more common on older frames.
This totally stumped me and caught me completely off guard!
So I built a bike for a friend. The frame is an old Kobe "Cobra". The cranks on the bike were 7 speed, with a six speed free wheel and an old Suntour Derailleur.
I converted the drive train to a seven speed with a a cheap Shimano "Altus" rear deraileur. I kept the original Altus Front Derailleur that came with the frame. I put on Salsa seven speed chain rings.
When I installed the drive train I had shifting problems. I noticed that the frame was slightly bent and the dropouts were bent and mis-aligned. I corrected those problems but continued to have shifting problems.
This is where my troubles began.
I tried every bit of troubleshooting I know of, from the Barnett's manual to Sutherlands, etc. But I could not get the shifting right.
I believe the problem was staring me in the face the whole time. When I put on another derailleur to check to make sure it just wasn't a shot derailleur, I noticed the derailleur hanger seemed a bit long. This seemed to make sense with some of the symptoms I observed.
I measured the distance from the dropout flat to the top edge of the derailleur mounting hole and compared them to mine and other bikes in my building, and sure enough, the hanger is a good 7mm longer than other derailleur hangers.
I called a couple local shops and they basically said "Huh? You're crazy!"
A passage in the Paterek frame builders manual says that cutting these hangers off and brazing on new ones are an easy and reasonable fix for bent and torn derailleur hangers.
Called local shops again with this idea and they said "Huh? You're crazy!"
So I',m thinking, just replace the derailleur hanger with a new one?
Has anyone heard of abnormally long derailleur hangers like this?
I'm thinking it's more common on older frames.
This totally stumped me and caught me completely off guard!
08-20-09, 02:18 AM
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Can buy an 'dérailleur hanger adapter claw' for a few dollars. From the below pic of a Kobe Cobra frame (may be diff from your frame...need pics), it should work:
08-20-09, 06:47 AM
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I agree pics would help. is this a MTB we are dealing with? you took off the 6spd frewheel/cassette, rearderailuer, and shifters correct? then you put a 'cheap' altus rearderailuer, and what other items? derailuer hangers come in all different chapes and sizes don't get hung up on the size of your hanger. if this bike is to index the hanger needs to be parrellel to the centerline of the frame both vertically and horizontally.
what type of shifters and freewheel are you using? pics please
what type of shifters and freewheel are you using? pics please
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
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08-20-09, 06:40 PM
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Thanks for the replies! Pics on the way..............
The frame is very similar to the one pictured above. But the derailleur hanger is definitely longer.
The shifters are Shimano 7 speed integrated with brake levers. Altus rear derailleur, Altus C20 front derailleur (which was on the frame when we got it and works great).
53/42 chainrings, 13/28 cassette I believe (?)
I've installed this particular derailleur/shifter combination on three other bikes, one of which is mine, all with no problems. Key difference is derailleur hanger length.
I found a schematic on one of these threads of Shimano's suggested distance from center axle to center derailleur mounting threads, which states 26-28mm. This derailleur hanger is about 35mm. (?) (The bike is currently not here and will be back tomorrow, converted to single speed temporarily).
The frame is very similar to the one pictured above. But the derailleur hanger is definitely longer.
The shifters are Shimano 7 speed integrated with brake levers. Altus rear derailleur, Altus C20 front derailleur (which was on the frame when we got it and works great).
53/42 chainrings, 13/28 cassette I believe (?)
I've installed this particular derailleur/shifter combination on three other bikes, one of which is mine, all with no problems. Key difference is derailleur hanger length.
I found a schematic on one of these threads of Shimano's suggested distance from center axle to center derailleur mounting threads, which states 26-28mm. This derailleur hanger is about 35mm. (?) (The bike is currently not here and will be back tomorrow, converted to single speed temporarily).
08-20-09, 06:46 PM
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An Altus rear derailleur isn't designed to work with SIS. It is really only a friction deraileur. It was actua;lly bult before SIS existed. Maybe you just got lucky the others worked.
08-20-09, 08:49 PM
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UH UM? there may have been a 'pre' index Altus but the altus name has been alive and well in indexing for years. https://techdocs.shimano.com/techdocs...ch_results.jsp
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
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Last edited by Bianchigirll; 08-20-09 at 08:55 PM. Reason: spelling
08-20-09, 09:30 PM
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I'm using a Shimano 105 free hub with a 7 speed cassette and spacers. Spacing from outside of right dropout to outermost cog is about 12-13mm (I played around a lot with this spacing to no avail).
What it seems to be is the length of chain between the jockey pulley and the cogs appears to be too long. It's so long that the derailleur has to shift too far for the chain to catch on the next cog. The metaphor I use is that a regular derailleur hanger works like pulling a red wagon by the handle. This longer derailleur hanger is like if you tied a rope to the handle of the wagon and pulled it around having to adjust that much farther to get around stuff on the sidewalk.
I aligned the hanger with an alignment guide and tool, the wheel is true. The dropouts and frame are aligned also.
Maybe the b screw stop can be modified somehow?
I'll have the pics up soon.
Thanks for everyone's feedback and time!!!
What it seems to be is the length of chain between the jockey pulley and the cogs appears to be too long. It's so long that the derailleur has to shift too far for the chain to catch on the next cog. The metaphor I use is that a regular derailleur hanger works like pulling a red wagon by the handle. This longer derailleur hanger is like if you tied a rope to the handle of the wagon and pulled it around having to adjust that much farther to get around stuff on the sidewalk.
I aligned the hanger with an alignment guide and tool, the wheel is true. The dropouts and frame are aligned also.
Maybe the b screw stop can be modified somehow?
I'll have the pics up soon.
Thanks for everyone's feedback and time!!!
