Chain ring - Ultegra
Discussion
I have had a series of chain breaks lately, including after the fitting a brand new chain.
I pulled the chainset apart, and noticed one of the rivets on the large chainring sticks proud.
Can any one comment if this is correct? - Thanks
Crank and chain rings done about 3k miles and cassette about 1k.
1st Image shows the protruding rivet, the 2nd the rear side of it, and the 3rd what the others look like (rear side)
I pulled the chainset apart, and noticed one of the rivets on the large chainring sticks proud.
Can any one comment if this is correct? - Thanks
Crank and chain rings done about 3k miles and cassette about 1k.
1st Image shows the protruding rivet, the 2nd the rear side of it, and the 3rd what the others look like (rear side)
BrundanBianchi said:
The ‘protruding rivet’ is there to stop the chain getting jammed between the crank and chain ring if you get an over shoot on the ring up shift. You have to ensure that the crank is aligned with the rivet.
Thanks, been over the rest nothing obvious that could result in 3 chain breaks in a month (150 miles).Is the easy answer to buy some new chainrings, a new cassette and yet another new chain ?
JPJPJP said:
How old was the chain that broke twice?
Was the new chain fitted correctly and did it marry with the old cassette ok?
The old chain broke once and then was replaced , the new chain has now broken twice.Was the new chain fitted correctly and did it marry with the old cassette ok?
The old chain was probaly 1k mile and 1 year old, not 'stretched' / worn, but replaced regadless, as I removed a few many links as part of the roadside repair.
As far as fitted correctly, I didnt swap the casstte, as it was replaced about 1k mile ago, but I also didnt use any 'quick links', instead used my chain breaker and pushed through a pin.
Kawasicki said:
Is it breaking where (or near where) you join it?
I’ve been riding for decades and never broke a chain.
First set of chian breaks in 10 years (10k+ miles) of riding.I’ve been riding for decades and never broke a chain.
It seems to be tearing the outer plate away, something must be catching it, all three times it broke as I dropped into the smaller chainring or went from small to large chainring.
Wilmslowboy said:
Kawasicki said:
Is it breaking where (or near where) you join it?
I’ve been riding for decades and never broke a chain.
First set of chian breaks in 10 years (10k+ miles) of riding.I’ve been riding for decades and never broke a chain.
It seems to be tearing the outer plate away, something must be catching it, all three times it broke as I dropped into the smaller chainring or went from small to large chainring.
Kawasicki said:
That’s interesting. Those pins are designed to help the chain shift from ring to ring ( essentially the chain hits them and drops / bounces on to the small ring) they shouldn’t look like that. It suggests that either your front mech indexing isn’t right, and the chain has been sitting on the pins for too long, or the pin has broken off, and if the chain then hit that, it would probably kill the chain.Wait a minute.
Pushed through a pin?
There are only two ways of joining a chain:
1) A 'magic' / removable link.
2) The special, chain specific joining pin that you push through, then snap off the end. It looks like a small bullet, comes with a new chain.
If you push a regular pin back in, it will never hold.
Sorry if stating the obvious, but what you describe is exactly what I would expect if a regular pin was 're-used' - pushing it out will remove the lip that holds the outer plate on, so it's free to spread and destroy it's self at the slightest provocation.
Pushed through a pin?
There are only two ways of joining a chain:
1) A 'magic' / removable link.
2) The special, chain specific joining pin that you push through, then snap off the end. It looks like a small bullet, comes with a new chain.
If you push a regular pin back in, it will never hold.
Sorry if stating the obvious, but what you describe is exactly what I would expect if a regular pin was 're-used' - pushing it out will remove the lip that holds the outer plate on, so it's free to spread and destroy it's self at the slightest provocation.
Edited by upsidedownmark on Monday 5th October 11:17
BrundanBianchi said:
That’s interesting. Those pins are designed to help the chain shift from ring to ring ( essentially the chain hits them and drops / bounces on to the small ring) they shouldn’t look like that. It suggests that either your front mech indexing isn’t right, and the chain has been sitting on the pins for too long, or the pin has broken off, and if the chain then hit that, it would probably kill the chain.
Nope, that's just the back of the 'chain drop' pin that protrudes behind the crank arm, not a shifting ramp. They do look like that (although that chainset looks a bit more chewed than the norm..)upsidedownmark said:
Wait a minute.
Pushed through a pin?
There are only two ways of joining a chain:
1) A 'magic' / removable link.
2) The special, chain specific joining pin that you push through, then snap off the end. It looks like a small bullet, comes with a new chain.
If you push a regular pin back in, it will never hold.
Sorry if stating the obvious, but what you describe is exactly what I would expect if a regular pin was 're-used' - pushing it out will remove the lip that holds the outer plate on, so it's free to spread and destroy it's self at the slightest provocation.
Ok - this may be the problem, I pushed out the pin, not all the wa, fliped the chain breaker and pushed it back in.Pushed through a pin?
There are only two ways of joining a chain:
1) A 'magic' / removable link.
2) The special, chain specific joining pin that you push through, then snap off the end. It looks like a small bullet, comes with a new chain.
If you push a regular pin back in, it will never hold.
Sorry if stating the obvious, but what you describe is exactly what I would expect if a regular pin was 're-used' - pushing it out will remove the lip that holds the outer plate on, so it's free to spread and destroy it's self at the slightest provocation.
Edited by upsidedownmark on Monday 5th October 11:17
Guaranteed that's it then! Simple / cheap fix at least 
Before you remove it the pin has a lip on both ends: I--I with a fat bar in the middle - when they make the chain it's put in then the ends are flared (basically a rivet). When you push it out it takes a lot of tension to break it, then it moves - if you were to look very carefully (perhaps with a magnifying glass), you'd see the side you pushed on has fractured the lip off - you have some very small bits of metal, and a fractured edge on the pin. It pushes back in easy enough, but it's now just I-- so when there's any load on the side plate, it just pings off the end of the pin.
The joining pins look more like |--> so the can be pushed in from one side. IMO the best answer is the magic links. They can also be handy for roadside fixes..
Before you remove it the pin has a lip on both ends: I--I with a fat bar in the middle - when they make the chain it's put in then the ends are flared (basically a rivet). When you push it out it takes a lot of tension to break it, then it moves - if you were to look very carefully (perhaps with a magnifying glass), you'd see the side you pushed on has fractured the lip off - you have some very small bits of metal, and a fractured edge on the pin. It pushes back in easy enough, but it's now just I-- so when there's any load on the side plate, it just pings off the end of the pin.
The joining pins look more like |--> so the can be pushed in from one side. IMO the best answer is the magic links. They can also be handy for roadside fixes..
Edited by upsidedownmark on Monday 5th October 22:59
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