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Pantograph stucked!

Old 04-18-14, 06:00 AM
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notreallyy
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Pantograph stucked!

Hi there, I just bought a new bike online and I used it just 1 time before finding out that the L and H screws weren't working, so I decided to unmount the front derailleur from the frame ( I removed the cable too) to check what was wrong and apparently the pantograph doesn't move even when using directly the screwdriver to trigger additional force. I don't see anything that could block it so I'm starting to think that the derailleur is a faulty one..

Should I open a warranty request to shimano or there's something I don't know ( I'm not an expert)?

The front derauilleur is a shimano FD m590 10 and here some photos:


http://oi57.tinypic.com/2jequmh.jpg
http://oi62.tinypic.com/66b3uh.jpg
http://oi59.tinypic.com/2e2qohy.jpg

Thanks in advance
Have a nice day
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Old 04-18-14, 06:25 AM
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Originally Posted by notreallyy View Post
. . . the L and H screws weren't working . . .
In what way were they not working?
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Old 04-18-14, 06:28 AM
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Originally Posted by notreallyy View Post
Hi there, I just bought a new bike online and I used it just 1 time before finding out that the L and H screws weren't working, so I decided to unmount the front derailleur from the frame ( I removed the cable too) to check what was wrong and apparently the pantograph doesn't move even when using directly the screwdriver to trigger additional force. I don't see anything that could block it so I'm starting to think that the derailleur is a faulty one..

Should I open a warranty request to shimano or there's something I don't know ( I'm not an expert)?

The front derauilleur is a shimano FD m590 10 and here some photos:


http://oi57.tinypic.com/2jequmh.jpg
http://oi62.tinypic.com/66b3uh.jpg
http://oi59.tinypic.com/2e2qohy.jpg

Thanks in advance
Have a nice day
Presumably by "pantograph" you mean the derailleur cage doesn't move? If not, did it ever work? Before or after you removed the screws?

If so, does it move when you pull on the cable? The activation force for a FD can be high, so you might need to temporarily use a pair of pliers. The FD is a pretty simple mechanical object, so it should be easy to see where it's hanging up.
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Old 04-18-14, 06:44 AM
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Basically, what happened is this: the chain was scratching the inside part of the cage (on the highest crown) so I tryed to use the H screw but it didn't do anything; at some point while trying to make it works (I don't remember how) the derailleur and the chain got stucked so I had to remove the derailleur from the frame (the screw still weren't working).

While remounting it, adjusting the low crown with the L screw, it didn't do anything because as you can see the screw stops when it touch the pantograph: (the cable is not set yet)

http://oi57.tinypic.com/ao10y.jpg

For pantograph I mean that thing on which the L and H screws operate to move the cage (in the picture above is the black thing under the screw)

Last edited by notreallyy; 04-18-14 at 06:48 AM.
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Old 04-18-14, 06:56 AM
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"Pantograph" can referee to any details that are cut/stamped out of the surface of the component. Think of the fancy chainrings with a logo cut into them.

Parallelogram is the usual name used for the moving elements of common ders. 4 links with pivots at each corner. The limit screws contact little tabs on one or more of the links. (For more understanding about ders and their designs/history get a copy of "The Dancing Chain" by Frank Berto).

The parallelogram pivots can get seized (rust, grit, oxidation). The screw threads same. The parallelogram's range of movement can be at it's extreme already. Objects can be wedged in the movement further limiting it.

The ft der is in the perfect position to receive a lot of spray from the rear tire. Put a bike away wet, muddy, still having a salt coating on it and it will soon enough become only a chain guide, not a der. Andy.
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Old 04-18-14, 06:58 AM
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Originally Posted by notreallyy View Post
. . . the screw stops when it touch the pantograph: (the cable is not set yet) . . .
That is as it should be.
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Old 04-18-14, 06:59 AM
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I suspect that this is probably a problem of your own making. I say this because from your post I can see you never bothered learning how the derailleur is supposed to work and how to adjust.

I can't say what's wrong now, but you should watch a few tutorials on FD set up and adjustment before playing with it any more, or enlist the help of someone who knows more. If there's a bike co-op nearby, that is probably your best option now.
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Old 04-18-14, 07:02 AM
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Originally Posted by notreallyy View Post
Basically, what happened is this: the chain was scratching the inside part of the cage (on the highest crown) so I tryed to use the H screw but it didn't do anything; at some point while trying to make it works (I don't remember how) the derailleur and the chain got stucked so I had to remove the derailleur from the frame (the screw still weren't working).

While remounting it, adjusting the low crown with the L screw, it didn't do anything because as you can see the screw stops when it touch the pantograph: (the cable is not set yet)

http://oi57.tinypic.com/ao10y.jpg

For pantograph I mean that thing on which the L and H screws operate to move the cage (in the picture above is the black thing under the screw)
Is the screw actually bottoming out? I.E. is it too short? That would be very, very unlikely. Presuming it's not, the H and L screws ideally need to be adjusted when they're not under any tension, which means you may need to use your hand to back the cage off so that you can get enough travel distance on the screw to get it adjusted correctly.
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Old 04-18-14, 07:04 AM
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Originally Posted by AnkleWork View Post
That is as it should be.
Isnt the screw supposed to move it?
Wait a minute, there's no need to set up the cable on the derallieur if I start to adjust it from the lowest crown right? On the lowest crown I should be able to use the L screw to adjust the cage on 0.5 mm from the chain while instead I need the cable set to adjust the other two crowns right? Or am I doing something totally wrong?

Last edited by notreallyy; 04-18-14 at 07:12 AM.
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Old 04-18-14, 07:09 AM
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Originally Posted by notreallyy View Post
Isnt the screw supposed to move it?
No, which is why I said you need to watch some tutorials before going forward. The cable, and ONLY the cable, moves the derailleur.

The limit screws do exactly what their name implies, set the inner and outer limits on the possible range of travel.

Seriously.

Seek out and watch some tutorials before you actually damage this. There are so many available, both in text and photo, or video, and they're FREE so you have no excuse for continuing to fiddle with this in ignorance.
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Old 04-18-14, 07:09 AM
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Originally Posted by notreallyy View Post
Isnt the screw supposed to move it?
Wait a minute, there's no need to set up the cable on the derallieur if I start to adjust it from the lowest crown right? On the lowest crown I should be able to use the L screw to adjust the cage on 0.5 mm from the chain while instead I need the cable set to adjust the other two crowns right? Or am I doing something totally wrong?
The screws are limiter devices. Trying to adjust the screws against the force of the return spring or cable tension is often a fine way to strip the screw head.

One problem is that you keep using non-standard terminology, which is likely confusing everyone. Probably the best thing to do at this point is to take a look at Park Tool Co. » ParkTool Blog » Front Derailleur Adjustments , and start from scratch with attempting the adjustments, if you don't want to take it to a shop or a coop, if you have a local one.
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Old 04-18-14, 07:18 AM
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Originally Posted by mulveyr View Post
The screws are limiter devices. Trying to adjust the screws against the force of the return spring or cable tension is often a fine way to strip the screw head.

One problem is that you keep using non-standard terminology, which is likely confusing everyone. Probably the best thing to do at this point is to take a look at Park Tool Co. » ParkTool Blog » Front Derailleur Adjustments , and start from scratch with attempting the adjustments, if you don't want to take it to a shop or a coop, if you have a local one.
Originally Posted by FBinNY View Post
No, which is why I said you need to watch some tutorials before going forward. The cable, and ONLY the cable, moves the derailleur.

The limit screws do exactly what their name implies, set the inner and outer limits on the possible range of travel.

Seriously.

Seek out and watch some tutorials before you actually damage this. There are so many available, both in text and photo, or video, and they're FREE so you have no excuse for continuing to fiddle with this in ignorance.


I'm sorry I should have told you before that I'm not a native english speaker, actually I'm following an Italian guide that says that I should be able to adjust the cage in this way; moreover that's the reason why I'm using a non-standard terminology (like pantograph).

I have already found the ParkTool guide but I don't understand some technical terms, and it's kinda hard to translate it correctly with the translator, that's why I asked on the forum!

Do you know any site that have the terminology linked to images for the front derailleur by any chance?

Last edited by notreallyy; 04-18-14 at 07:25 AM.
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Old 04-18-14, 07:18 AM
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Originally Posted by mulveyr View Post
The screws are limiter devices. Trying to adjust the screws against the force of the return spring or cable tension is often a fine way to strip the screw head. . .
Not only that, it also may not produce an accurate adjustment since the stop does not work that way in use.
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Old 04-18-14, 07:31 AM
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Originally Posted by notreallyy View Post
I

Do you know any site that have the terminology linked to images for the front derailleur by any chance?
Offhand I don't know of any, but maybe a video is better for you. Watch a few, and try to integrate it with what you saw on the Park site, and see if you can get it to come together in your head before actually starting in on the job.
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Old 04-18-14, 10:19 AM
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A pantograph is a mechanical device for duplicating and scaling drawings or patterns. Note "graph" in the word. Some other mechanisms that move in a similar way, notably the overhead contact arms for electric trains, are sometimes also called pantographs.

https://www.google.com/search?q=pant...=1524&bih=1017
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Old 04-18-14, 11:30 AM
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Originally Posted by Looigi View Post
A pantograph is a mechanical device for duplicating and scaling drawings or patterns. Note "graph" in the word. Some other mechanisms that move in a similar way, notably the overhead contact arms for electric trains, are sometimes also called pantographs.

https://www.google.com/search?q=pant...=1524&bih=1017
Yes, the copying, and enlarging or reducing devices have been around for 400 years or so, but folks steal names all the time. So if it was OK for Siemens to do so, it's equally OK for bike folks to call the articulating parallelogram part of derailleurs the same thing.

Many of us have been calling these pantographs for years, even though we never used them to copy anything.
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Old 04-18-14, 03:19 PM
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Originally Posted by FBinNY View Post
...Many of us have been calling these pantographs for years, even though we never used them to copy anything.
Personally, I'm unfamiliar with that usage, and so is the internet, the little I checked. Back in 5th or 6th grade I made one, the drawing scaling type, to bring to school as a science project. That was sometime back in the early 60's.
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Old 04-18-14, 04:37 PM
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Should I open a warranty request to shimano or there's something I don't know ( I'm not an expert)?
warrantee service flows back upstream from the retail end, so start from where you bought the bike.


What is your time worth? , buying a new replacement Front derailleur may be worth not squandering

more than a few hours of your life.

trying to get a free one.

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Old 04-19-14, 12:17 AM
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Initially I was really confused reading this but when I really thought about it a derailleur does have a pantographic movement. Makes perfect sense. Thanks, I learned something.
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Old 04-19-14, 02:33 AM
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This site shows some bicycle 'anatomy: here


Front Derailleur Anatomy


Attached Images
File Type: gif
pict_frtder_f.gif (29.7 KB, 10 views)

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Old 04-19-14, 03:45 AM
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This whole thread highlights the issues of buying a bike on-line when the purchaser has no knowledge of how to set the bike up. For the OP, would suggest initially getting a LBS to get a bike set up.

Asking questions on a forum is great, but in this case, getting some hands on assistance would seem a better option. Hope you still have the screw that are missing from the FD, as these are needed for correct operation.

For English not being you first language, have you tried Italian tech docs Shimano, these are the Shimano how to's, and will assist you in setting up any Shimano product.
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