Chain Wrapping Up On Itself When Changing To The Smallest Chainring: Any Ideas?

[Ming the Merciless]

I'm trying to source a new derailleur but I'm struggling a bit.

My hanger is standard mount but all of the stuff I see on Amazon is tagged "Direct Mount" although quite a few of them look like standard mount to me.

This one is tagged "direct attachment "?

View attachment 569122

I might just bite the bullet and buy one that looks right and if it isn't right, send it back.

Earlier you said a new derailleur was on the way. Puzzled?

 

[Lovacott]

It sounds like your derailleur spring could be toast then or your pivot points gummed up, can you push it back gently by hand and have you cleaned and lubricated it well?

As for your scenario, I have never had a problem dropping down the rings, I would stay in the big ring and move up the cassette bit by bit until about halfway then when I need to switch to a smaller ring easy off slightly during the change.

Changing down on the front, even with a minimal load, is very "crunchy" so I tend to do my front changes down when I'm either on the flat or downhill under zero load.

I've tried leaving the change until after I begin the ascent but any load at all throws the chain onto the frame.

If I adjust the limit stop just enough to stop the chain coming off, the gear change takes almost a lifetime.

I've spent hours following Park Tools instructional YouTube videos to the letter but to no avail.

 

[Lovacott]

Earlier you said a new derailleur was on the way. Puzzled?

I cancelled because I wasn't sure whether or not it was "standard" or "Direct".

Ordered another one about 20 minutes ago.

 

[Ajax Bay]

This is chain suck and changing the rear derailleur will have minimal beneficial effect to that (although you have said the cage is bent and the current RD old so you need a new one - but why 'direct mount'?). See the last 'chain suck' thread on here (last month?). Edit: this one: https://www.cyclechat.net/threads/p...-when-in-the-small-gears.269738/#post-6228182

How old is the chain? Newish?
Probably the best remedial action (assuming the chain and chainrings are reasonably clean) is to replace the inner ring.
While waiting for that, check that your chain is the correct length. Could you remove a link yet still have the chain on large/large? If so do that.
Detail from link:
"This is a useful and comprehensible article: http://fagan.co.za/Bikes/Csuck/ (referenced from Sheldon Brown's site).
A mitigation I used (and actually have left it there) is a chunky ziptie round the right chainstay up where the chainstay joins the BB shell. The idea was that a chain about to suck would knock against the ziptie and 'un-suck'."

 

[Lovacott]

This is chain suck and changing the rear derailleur will have minimal beneficial effect to that (although you have said the cage is bent and the current RD old so you need a new one - but why 'direct mount'?). See the last 'chain suck' thread on here (last month?). Edit: this one: https://www.cyclechat.net/threads/p...-when-in-the-small-gears.269738/#post-6228182
How old is the chain? Newish?

The one I've ordered states direct mount in the description but it doesn't look like an exclusive direct mount to me? Fact is, it looks exactly like what I have already got so I ordered it and as it's due to arrive tomorrow. I'll find out soon .

The chain is only three weeks old and the chain checker on the 0.05% side doesn't even begin to go in.

I now understand the concept that crossing the chain small to small means that the inboard side of each chain link adds some unwanted grab to the chainring. This would be aided and abetted by poor lubrication and dirt but possibly negated by a decent bit of tension from the rear mech along with good indexing (plus a zip tie ).

The crankset is only four months old and I've had a good look at it this morning and there are no burrs or any noticeable instances of wear on any of the teeth.

With the bike upside down and looking down, there appears to be no distortion or wobble in the chainrings.

 

[Ajax Bay]

The chain is only three weeks old and the chain checker on the 0.05% side doesn't even begin to go in.

And you didn't get chain suck on the old chain, did you? Look at the triangle: 'new' chain = increased risk.
This chain suck won't go away: you need make a change. Recommend chain shortening (with large/large proviso) as first step.
You shared an image of the chain suck. What about a photo, from the side, of your RD with the chain on small/small?
Size of chain rings (eg 48-38-28) and size of cassette (eg 11-32)??

 

[Lovacott]

And you didn't get chain suck on the old chain, did you? Look at the triangle: 'new' chain = increased risk.
This chain suck won't go away: you need make a change. Recommend chain shortening (with large/large proviso) as first step.
You shared an image of the chain suck. What about a photo, from the side, of your RD with the chain on small/small?
Size of chain rings (eg 48-38-28) and size of cassette (eg 11-32)??

My chain length is based on the length of the original (which I still have as the "benchmark").

My current link count exactly matches the original link count (when I first bought the bike).

The more I think about it, the more I am swayed towards the idea that the rear mech tension spring is shafted.

 

[Lovacott]

And you didn't get chain suck on the old chain, did you? Look at the triangle: 'new' chain = increased risk.

I fitted the new chain over three weeks ago and I've had no issue until this week.

 

[Darius_Jedburgh]

Everybody is out of step apart from our Johnny!!!

 

[Ajax Bay]

My chain length is based on the length of the original (which I still have as the "benchmark").
My current link count exactly matches the original link count (when I first bought the bike).

I dgaf what length your 'original chain' is/was. Just check and if you can, remove a link (well 'if you can' remove two (each link is one inch btw)).
I advised (upthread): "Check that your chain is the correct length. Could you remove a link yet still have the chain on large/large? If so do that."
"I fitted the new chain over three weeks ago and I've had no issue until this week." If your point is that: 'therefore it can't be the chain' then you're wrong: it could be - chain suck is worst with a new chain ceteris paribus.
If your general point is: I have bought a new 'direct mount' RD and life will OK after I fit it: best of luck. Would still like to see the image of the RD and chain in small/small.

 

[Lovacott]

Everybody is out of step apart from our Johnny!!!

Latest boring update..

It's occurred to me that I finish my ride every day by going half way up one of the steepest residential streets in Britain in granny gear. I then leave the bike in the granny gear until I next use it.

I therefore park my bike overnight (or over the weekend) with a fair bit of opposing force on the rear derailleur which in turn, weakens the spring.

The lack of spring tension allows friction (between the sides of the small ring and the chain), to lift the weight of the chain and wrap it around the chainwheel.

 

[Darius_Jedburgh]

I therefore park my bike overnight (or over the weekend) with a fair bit of opposing force on the rear derailleur which in turn, weakens the spring.

The lack of spring tension allows friction (between the sides of the small ring and the chain), to lift the weight of the chain and wrap it around the chainwheel.

Post of the year.
Just brilliant. Utter tosh, but brilliant tosh.

I'm sorry if you think I'm being sarcastic but you have a problem that you don't understand. You ask for help. You receive many replies all more or less saying the same thing. You dismiss everything anybody says in favour of your own theories.
If you know so much about the problem why did you ask for help?

 

[Lovacott]

I dgaf what length your 'original chain' is/was. Just check and if you can.

Tad aggressive there mate. Calm down will ya .

I've been sizing my new chains based on the original, because the original worked like a treat.

On the subject of chain length, can you fathom this?

 

[Lovacott]

Post of the year.
Just brilliant. Utter tosh, but brilliant tosh.

I'm sorry if you think I'm being sarcastic but you have a problem that you don't understand. You ask for help. You receive many replies all more or less saying the same thing. You dismiss everything anybody says in favour of your own theories.
If you know so much about the problem why did you ask for help?

The standard response to this thread has been that I am doing everything wrong and I don't have a clue.

(Hence, my post footer.)

But mixed in amongst the contemptuous, patronising, know it all and sometimes vitriolic replies, there have been a few gems of wisdom which will get me over my problem.

Thank's for your input.

 

[Darius_Jedburgh]

Time to hit the ignore button.