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Re: Di2 chain
Posted: Wed Oct 04, 2017 11:14 am
by Timmy269
grover wrote:I can't think of a circumstance where the chain spontaneously drops off the big chainring to the small except when the chainring is worn, the chain is sloppy side to side and you're in a gear that makes quite a chainline. Say 53-28/25/22. The big ring teeth are no longer tall enough to hold the chain on the teeth against the angle that is pulling it towards the little ring (especially happens if you do half a pedal backwards when shifting your weight cornering/descending).
I don't know your yearly mileage, conditions or maintenance but three years is a long time for a set of rings to last for anyone in my opinion. I'd replace the chainrings and the chain. Given the likely worn chain is not skipping on the cassette, I'd say the cassette is shot too. Again, three years on a cassette is a long time.
Your chains aren't lasting very long now because your putting them on worn chainrings and cassette. You get away with it a few times but now it's just not working. A new chain only will probably remedy the issue for a short period because it will be stiffer laterally. But it will wear quickly.
My vote is to replace your chainrings, chain and cassette. And given the chain has dropped onto the bottom bracket a few times it sounds like your limit screw and chain catcher position need a tweek.
I thought that if the teeth of the cassette and chainrings had points they are worn out
Re: Di2 chain
Posted: Wed Oct 04, 2017 11:14 am
by Weenie
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Re: Di2 chain
Posted: Wed Oct 04, 2017 12:41 pm
by goodboyr
With all due respect, you’ve got some opinions to act on now. I’m not sure what the point is of further discussion. At least the chain, and in others option the rings and cassette too. When you get your new stuff you can hold it up side to side to compare and see the wear.
Re: Di2 chain
Posted: Wed Oct 04, 2017 12:50 pm
by Delorre
grover wrote:I can't think of a circumstance where the chain spontaneously drops off the big chainring to the small except when the chainring is worn, the chain is sloppy side to side and you're in a gear that makes quite a chainline. Say 53-28/25/22. The big ring teeth are no longer tall enough to hold the chain on the teeth against the angle that is pulling it towards the little ring (especially happens if you do half a pedal backwards when shifting your weight cornering/descending).
I don't know your yearly mileage, conditions or maintenance but three years is a long time for a set of rings to last for anyone in my opinion. I'd replace the chainrings and the chain. Given the likely worn chain is not skipping on the cassette, I'd say the cassette is shot too. Again, three years on a cassette is a long time.
Your chains aren't lasting very long now because your putting them on worn chainrings and cassette. You get away with it a few times but now it's just not working. A new chain only will probably remedy the issue for a short period because it will be stiffer laterally. But it will wear quickly.
My vote is to replace your chainrings, chain and cassette. And given the chain has dropped onto the bottom bracket a few times it sounds like your limit screw and chain catcher position need a tweek.
I totally agree here!! I've recently began to have similar issues on some occasions, but it happens only when in the big ring and with cross chain with the third last cog (I don't go higher when in the big ring). And yes, the chainrings have 25.000 km's and the chain is due for replacement also. Never had drops in the past, even when the chain was due for replacement. So, my vote also goes toward changing chain AND chainrings (and cassette if it has already seen a couple of chains)
Re: Di2 chain
Posted: Wed Oct 04, 2017 1:52 pm
by glepore
Not to pile on, but the photos of the big ring show obvious wear. To the point of shards hanging.
Re: Di2 chain
Posted: Wed Oct 04, 2017 11:31 pm
by djbowen99
That chainring looks terrible, are you cross chaining a lot? the teeth look oddly worn.
Re: Di2 chain
Posted: Thu Oct 05, 2017 2:43 am
by ddsg
Have the same problem on my older 10 speed Di2 setup. Chain is fine (checked with chain tool) and chainrings don't seem worn... Will be curious to see what fixes it in your case.
Re: Di2 chain
Posted: Thu Oct 05, 2017 3:31 am
by goodboyr
Those chain checkers don’t show pin to pin wear. Take a 12 inch steel ruler and check pin to pin with the chain stretched tight. I bet you’ll see wear of 1/8 or more even though your chain checker says it’s ok.
Re: Di2 chain
Posted: Thu Oct 05, 2017 3:59 am
by MoreRideTime
This link:
http://pardo.net/bike/pic/fail-004/000.html provides some info all about chain measurement and different chain measurement devices. Hope it provides some further info for you to figure out the issue.
Re: Di2 chain
Posted: Thu Oct 05, 2017 12:58 pm
by Timmy269
Thanks, in the meantime I have mailed the photos of the chainrings to the Rotor Distributor and according to him there is wear but not so that they need to be replaced.
This evening I will measure the chain wear
Re: Di2 chain
Posted: Thu Oct 05, 2017 2:29 pm
by wingguy
Timmy269 wrote:I thought that if the teeth of the cassette and chainrings had points they are worn out
Points?
If your chainrings have points then they are ULTRA worn out
Re: Di2 chain
Posted: Thu Oct 05, 2017 4:41 pm
by Timmy269
Oké, my chain looks worn out I think.
I will buy a new one and see if that's better
Re: Di2 chain
Posted: Fri Oct 06, 2017 7:45 am
by Timmy269
What's the best choice, Shimano chain or KMC chain
Re: Di2 chain
Posted: Fri Oct 06, 2017 8:20 am
by Ritxis
Timmy269 wrote:What's the best choice, Shimano chain or KMC chain
Shimano CN-HG601 (105) Pay more than it costs this, is to waste money