Di2 chain

Discuss light weight issues concerning road bikes & parts.
Timmy269
Posts: 176
Joined: Tue Nov 25, 2014 2:34 pm

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

by Weenie


goodboyr
Posts: 1391
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

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.

Delorre
Posts: 959
Joined: Sat May 24, 2014 12:09 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)

glepore
Posts: 1114
Joined: Thu Mar 28, 2013 4:42 pm
Location: Pa USA

by glepore

Not to pile on, but the photos of the big ring show obvious wear. To the point of shards hanging.
Cysco Ti custom Campy SR mechanical (6.9);Cannondale SS Evo Di2 7970 (5.79); Willier Cento Uno Air Di2 9070 (7.0); C40 Mk2 DA 7800 ; Anvil Custom steel Etap;1996 Colnago Technos Record

djbowen99
Posts: 72
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

That chainring looks terrible, are you cross chaining a lot? the teeth look oddly worn.

ddsg
Posts: 34
Joined: Sun Dec 08, 2013 10:30 pm

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.

goodboyr
Posts: 1391
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

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.

MoreRideTime
Posts: 123
Joined: Sun Sep 17, 2006 9:09 pm
Location: Canada

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.

Timmy269
Posts: 176
Joined: Tue Nov 25, 2014 2:34 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

wingguy
Posts: 3942
Joined: Thu Mar 08, 2012 11:43 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 :shock: :wink:

Timmy269
Posts: 176
Joined: Tue Nov 25, 2014 2:34 pm

by Timmy269

Oké, my chain looks worn out I think.
I will buy a new one and see if that's better
Image

Timmy269
Posts: 176
Joined: Tue Nov 25, 2014 2:34 pm

by Timmy269

What's the best choice, Shimano chain or KMC chain

Ritxis
Posts: 240
Joined: Fri Jun 01, 2012 3:00 pm
Location: San Sebastian

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

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