# Chain Tangle!



## wrongway (Jul 31, 2020)

Well, I had a couple good days, then this...... No idea why? It'll shift the rear fine, tightly, but fine. Occasionally it'll slip, but I can feather it where it should be. (maybe that's not fine) The front was doing ok till this morning. Coming back from work and this after I shifted to high. Is this why these derailleurs are hated? Maybe I need to replace it with something else? I would want to keep the shifters, though.


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## juvela (Jul 31, 2020)

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you cannot be "pile driving" when you shift, the chainset needs to be moving however.  pedal pressure should be light to moderate when shifting.

the chain appears new; is it a full width 3/32" derailleur chain or is it one of the narrow ones?  a standard width 3/32" is preferable for your drive train.

are chainwheels straight?  would be wise to check them now following this derailment.

is front derailleur cage in good alignment with chainwheels when viewed from above?

is front derailleur mounting bracket snug?

are all three chainwheel bolts tight?  are the three chainwheel spacers all identical?

manufacturer of chainset offers chainwheel spacers in 3.5mm thickness and in 4.5mm thickness.  if you have the 4.5mm size you could change to the 3.5mm size:





event unlikely to be due to front mech itself.

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## wrongway (Jul 31, 2020)

juvela said:


> -----
> 
> you cannot be "pile driving" when you shift, the chainset needs to be moving however.  pedal pressure should be light to moderate when shifting.
> 
> ...




I never really ride aggressively so that might not be it. However, is it possible that with this one I need to be pedaling even less? 
I never knew there were different widths of chain and I threw the package away. I may have to put the old one back on.
Looks like I'll have to check all the alignments.


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## juvela (Jul 31, 2020)

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"pile driving" does not refer to how hard you are riding

it refers to those occasions when you are in a gear too tall for a given uphill slope and your pedalling slows down to just a very few rpms

the chain visible in the photo appears to be a modern asian one

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## wrongway (Jul 31, 2020)

juvela said:


> -----
> 
> "pile driving" does not refer to how hard you are riding
> 
> ...



Modern Asian being bad in this case? Maybe I was too quick to shift to high? I was on the flat, but maybe that's part of the problem.


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## SKPC (Jul 31, 2020)

Try to remember these drivetrains need matching components in order to work seamlessly.  And, mixing old drivetrain parts with new can create more problems.   Seems like from the beginning you had non-original chainring bolts on the crank and perhaps the wrong chainring spacers.   If your chain can fall between the chain rings, the spacers are too large, creating too wide of an opening between the rings that allow for the chain to potentially fall into the gap....as it did.   Or the chain as mentioned could be the wrong width(too narrow)....or both.  Those two and perhaps even the height of your front derailleur mounting height on the seat tube could be involved....it looks too tight to the big chainring in your photo..raise it a bit.  DO NOT go back to the old chain.  Just make sure the new one matches the width of the old one...and it is possible that the old chain was wrong to begin with. Too much info but you will figure it out..takes time. You hopefully have a repair stand you can put the bike up on to shift through the rings while you pedal the cranks with your hand.


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## all riders (Jul 31, 2020)

if it was working well for a while and then this--perhaps a dot of thread-lok on the limit screw.


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## wrongway (Jul 31, 2020)

I made it home.....barely. I shifted to high side in the front, or 10th. The chain twisted up. This time I rocked the pedals back and forth to continue forward and then shifted down. I put the bike in the stand and noticed that there is a point of binding, I assume the chain. This may be the problem.


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## juvela (Jul 31, 2020)

wrongway said:


> I made it home.....barely. I shifted to high side in the front, or 10th. The chain twisted up. This time I rocked the pedals back and forth to continue forward and then shifted down. I put the bike in the stand and noticed that there is a point of binding, I assume the chain. This may be the problem.




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perhchance the result of your use of the chain rivet press...

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## wrongway (Aug 1, 2020)

juvela said:


> -----
> 
> perhchance the result of your use of the chain rivet press...
> 
> -----



Well, this chain has a small ‘click’ or ‘snap’ attachment. I just ran it through all the rear gears and it caught and became hard to to pedal. I’m definitely thinking I’d better get a decent chain!


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## wrongway (Aug 1, 2020)

As I’m pedaling I can hear a ‘thump’ sound as the chain (I suppose it’s the chain) drags or catches.


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## juvela (Aug 1, 2020)

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sounds like an economy asian drive chain, Walmart?


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## wrongway (Aug 1, 2020)

I figured out the thumping, dragging 




chain. The cotter had worked loose ever so slightly sending two of the three bolt heads into the frame.  Now, to see if that is what caused the chain to come off the track. It works nearly flawlessly on the stand.


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## juvela (Aug 2, 2020)

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perhaps you need to make or purchase a cotter pin press to get them well seated

a c-clamp with a socket from a socket set can be used for both seating and removal:





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## wrongway (Aug 2, 2020)

juvela said:


> -----
> 
> perhaps you need to make or purchase a cotter pin press to get them well seated
> 
> ...



Oddly enough I have no trouble taking them apart. I have a workbench vise that is not bolted down and a used hospital table to lay it on. With that combination I have no trouble removing them. I don’t usually think to seat them the same way.


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## juvela (Aug 2, 2020)

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if you ever reuse wedgebolts it is good to take a file and file down the old seating mark until it disappears

reusing pins without doing this can impair the seating...


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