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 Post subject: Trouble with chain slip
PostPosted: Wed Jul 17, 2013 10:42 pm 
Dirt Disciple

Joined: Mon Nov 22, 2010 8:48 pm
Posts: 23
Location: Newcastle
Hi guys, sorry if this is in the wrong section!

As some of you may know I've recently gotten a hold of a Raleigh Randonneur that I've started working on. Now, the bike didn't come with a derailleur, and how silly of me it was to think I could simply bolt a new one on! The rear hanger was completely threaded, so much so I could simply push the new one all the way through the hole. So, while I'm waiting for the LBS to order in a dropout saver, I'm using a cheap clamp-on derailleur to use in the meantime (something like this http://compare.productwiki.com/shimano-rd-ty18/#gallery.

So far so good, right? Wrong.

On my first ride, I could barely pedal without the chain slipping and making a horrendous noise. Bear in mind, this was with a brand new chain. So, I bought some new (well, second-hand but still plenty of life left) chainrings, as it appeared to be slipping at the front. Also, there seems to be little wear to the rear cassette. But no, the problem was still there.

I took it out for a ride just now after fitting the chainrings, and although the problem seemed to be SLIGHTLY better (the old ones were completely worn) the chain was still slipping like crazy, and kept jumping off the chainset and jamming itself. However, I kept on going and up a slight incline not only was it slipping to the point I was at almost a standstill, but the chain snapped and bent the pin! I had noticed earlier that half of a link had dislodged itself (I hope that makes sense) but thought nothing of it and assumed I must have been careless when fitting the chain.

Also, I know it;s not the freehub that is worn, as I used it without issue as a single speed the other day to get to work.

To make matters worse, some little s**t slashed my front tyre while I was at work the other day, so I need to fix this one enough to get me to work and back tomorrow! Needless to say I'm not too happy!

Anyway, that leaves either the cassette or the derailleur at fault. I have a feeling that the cheap derailleur I'm using simply isn't tensioning the chain enough, and as a result the chain is slipping through it; I've compared it to the one I plan on fitting, and the spring is MUCH stronger on that one.

Also, I'm using a friction shifter (bar-end) at the moment, it has no trouble moving the derailleur, but maybe the lack of indexing may be causing the problem?

Would a weak derailleur spring cause slipping like this? Would fitting my new derailleur fix the problem? Is it an issue of a lack of indexing? Have any of you guys experienced anything like this?

Also, I have included a few photos to illustrate what is going on here.

Image

Image

Image

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Image

I really appreciate any input you guys have for me, I'm tempted to throw the thing in a skip right now!!!

Joe


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PostPosted: Wed Jul 17, 2013 11:09 pm 
Devout Dirtbag

Joined: Sat Aug 11, 2012 12:25 am
Posts: 147
Location: Shrewsbury
If you throw it away could you tell me which skip you use?! Have you checked if the right crank nut is tight. Maybe it's wobbling about knckering the chain link? Just a wild guess.


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PostPosted: Wed Jul 17, 2013 11:20 pm 
Retro Guru

Joined: Mon Jul 20, 2009 6:27 pm
Posts: 619
My guess is that the cassette and/or chain rings are too worn or that the indexing is not quite right. I reckon at least some of the cogs in the cassette look pretty worn to me.

I doubt the mech is the problem. Even the cheapies do the job.


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PostPosted: Wed Jul 17, 2013 11:30 pm 
Dirt Disciple

Joined: Mon Nov 22, 2010 8:48 pm
Posts: 23
Location: Newcastle
Yeah, the crank nut is tight, although the big ring does have a slight wobble. However, seeing as it slips on all 3 rings, possibly least on the large one, and the fact it worked fine as a single-speed leads me to think that that may not be the cause.

As for wear, both the chain rings and cassette seem fine, and it doesn't seem to happen more in one gear than another. As for indexing, there is no indexing as I use friction shifters, allowing me to fine-tune it as I need.

I'm honestly at a loss here!


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PostPosted: Wed Jul 17, 2013 11:36 pm 
Devout Dirtbag

Joined: Sat Aug 11, 2012 12:25 am
Posts: 147
Location: Shrewsbury
Is it possible that the geometry is out on the RD hangar? What could the reason have been for stripping the thread in the first place I wonder? Is the backend on the piss in relation to the rest of the bike, thus twisting the chain?


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PostPosted: Wed Jul 17, 2013 11:50 pm 
Dirt Disciple

Joined: Mon Nov 22, 2010 8:48 pm
Posts: 23
Location: Newcastle
Hmmm, not something I'd thought of until now; I'll have a look tomorrow and see what state it's in. That said, I'm not even using the hanger that's on there at the moment, just a clamp-on one, but if the whole back end is out then that could be causing some problems.

If it is out, is there any way of fixing it or is a new frame needed?


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PostPosted: Wed Jul 17, 2013 11:59 pm 
Devout Dirtbag

Joined: Sat Aug 11, 2012 12:25 am
Posts: 147
Location: Shrewsbury
Cold setting the back end woud fix it. Like I said, I'm only guessing but a quick eyeball from the back end looking forward woud tell you quickly enough. Seems unlikely to me that a damaged thread combined with faulty shifting is mere coincidence.


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PostPosted: Thu Jul 18, 2013 12:02 am 
Devout Dirtbag

Joined: Sat Aug 11, 2012 12:25 am
Posts: 147
Location: Shrewsbury
Also is that RD not rotated too far forward? If you moved it rearwards it would look more normal to my old, beer-riddled eyes!


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PostPosted: Thu Jul 18, 2013 10:47 am 
retrobike rider
retrobike rider
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Joined: Sun Dec 18, 2011 10:42 pm
Posts: 2189
Location: milton keynes
That cassette looks toast to me.


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PostPosted: Thu Jul 18, 2013 11:22 am 
Old School Grand Master
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Joined: Tue Oct 04, 2011 4:15 pm
Posts: 3499
Location: Behind you with the duct tape pulled out.
Chute55uk wrote:
That cassette looks toast to me.


+1


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