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Noise made by rear derailleur guard because I dont know how to fix it

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Noise made by rear derailleur guard because I dont know how to fix it

Old 03-23-17, 06:13 AM
  #1  
george2017
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Noise made by rear derailleur guard because I dont know how to fix it

I bought my first ever bicycle and its very used but before I replace any parts or I buy a newer one, I'd like to fix what I have. A picture speaks a thousand words so I'll start with that. (seems like I can not post urls until I have 10 posts but I'll try to upload it)


At the bottom you can see in the middle of the picture the guard touches the chain, (when I use the small cog). The chain no longer touches the guard when I use larger cogs (lower gear).

Although I watched a tutorial about fixing (different?) derailleur, it is not clear to me
- in what order the operations have to be done ?
- what is the start point ? (like put the chain on the cog or in the upper cog)

I can remember what the 2 screws H and L do, but I saw there is one more screw where the wire cover stops. I think in this case writing the instructions in order in which are performed would be very helpful.

Thank you for anyone who has any idea and would like to contribute.
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Old 03-23-17, 06:25 AM
  #2  
jj1091
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Looks like you have too much chain. Not seeing other pics of the bike, it's a guess that it has a different freewheel than original, or the derailleur is a replacement. You need to take a few links out of the chain, enough to keep the chain from hitting the guard.
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Old 03-23-17, 06:36 AM
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dsbrantjr
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Originally Posted by jj1091 View Post
You need to take a few links out of the chain, enough to keep the chain from hitting the guard.
Make certain that you leave the chain long enough that you can easily shift into the big front chainwheel and big rear cog without straining anything. Test this by turning the cranks by hand and gently shifting; STOP if anything gets tight.


You will need a chain tool to break the chain and I would suggest using a master link/quick link to reclose it. Using a master link you can easily shorten the chain 1 link at a time until you get it right.
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Old 03-23-17, 06:37 AM
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Juan Foote
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Well, to be honest, small to small is a ring combo you likely will not use considering that the chain rub on front should be significant.

Before you go knocking links out of the chain. Run biggest to biggest (also an unlikely combo) and see how much "slack" you have left in the der. tension/chain. There really shouldn't be a lot left there, and more likely than not you will see the leftover on that end as well. IF you find that you have run out of length on that side you could be running a gear combo that the der wasn't designed for.

So, assuming you get the chain length issue sorted, you should be able to take cable loose, adjust the screw for "small cog", pull cable taunt/tighten, run up to "big cog" and set limiter there. Fine tune.

EDIT- Something else to mention just by looks. Make sure your hanger (the part the der is hooked to) and cage are both "flat on plain" with the cogs. Considering the heavy scrapage shown in the pic it's pretty likely it has a twist or bend. It will not adjust correctly so long as that exists.

Last edited by Juan Foote; 03-23-17 at 06:42 AM.
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Old 03-23-17, 08:45 AM
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Thanks for all the answers!

Even though I don't have enough experience, I expected to be a problem with the chain being too long. I also ordered tools recently, will have to wait some time.

Actually I also made an adjustment some time ago and I removed the front system to change gears, so now I only use the front small chainwheel. So yes, the combo front wheel with back small cog is used quite often when I need the maximum speed. There are lots of hills, so I dont need lots of speed in this area, either uphil or downhil.

I confirm that this bike was created from some parts, I can see it lacks original direction-handle, or the maximum number of speed supported by the cable system is a little different.

Thank you, I think its good to make experiments with it before buying a more expensive one.
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Old 03-23-17, 11:57 AM
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Originally Posted by george2017 View Post
Actually I also made an adjustment some time ago and I removed the front system to change gears, so now I only use the front small chainwheel.
I think this affirms the notion that the chain can be safely shortened. The chain was originally long enough to allow for the big-big combination that was on the bike at the factory. If you need to err either way, you'd rather have derailer cage rub in small-small than have the whole system lockup or bind if the chain is not long enough in big-big.
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Old 03-23-17, 02:59 PM
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Originally Posted by george2017 View Post
Actually I also made an adjustment some time ago and I removed the front system to change gears, so now I only use the front small chainwheel.
That was your first mistake. Front derailleurs do not only serve as gear changers, they also keep your chain from falling off the chainrings
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