Cassettes have life expectancies of over 10,000 miles. I'd suspect frame flex or possibly a short in the wiring? Don't have any experience with electronic.
Are you referring to actual 'shifts' in the cassette or intermittent 'clicks' of the chain as it latches onto the ramps of the cassette and then drops off?
If its the latter, possibly its the chainlink.
I had a similar issue with my bike (Colnago EPS) with DA Di2. Was using the original Shimano 7900 quicklink. Couldn't resolve the issue completely from fine tuning the adjustments with the Di2.
Swapped out the quicklink for a KMC one, did one adjustment for it and it was all cleared.
The DA Di2 is quite finicky with the chain. Especially if you're using the 7900 chain as its directional.
You could swap out to a chain which is completely uniform and see if you still have the same issues. KMC x10SL works good on Di2 btw ....
It sounds like what I described above. Either that or you should check your freehub ratchet.
Quick check is to go to your LBS and ask to borrow a good condition chain of the correct length with a good quick link. And go for ride to see if you have the same issue.
While there, you could ask them, if they are willing to do the favour to check your wheelset freehub ratchet.
Note too: the RD hanger straightness can't be discerned just by the naked eye. Many people, even mechanics have issues with this!
If the chain is what you describe, it most probably is the culprit. Its a phenomenon which probably prompted Shimano do do away with the quick link in its chains after initial launch. Like mentioned, the system used with the 7900 series chains are a little finicky when it comes to chain.
That tiny bit of chain is probably the cause. It latches onto the cog ramps and then drops off.
A standard Shimano 10-speed compatible chaintool is fine. But the pin just needs to be the correct one as between 7900 and 7800, there seems to be some differences as you'll notice that the 7900 chains have a perfectly flushed facade for the pins compared to the 7800.
If you're not sure, ask your LBS if they can help on that. I'm sure they have the 7900 pins. Or ask them for the KMC quicklink for Shimano 10-speed. Its probably US$7-8 at the shops (if the price is internationally homogenized) ...
My chain tool is a Park chain tool from the mid-90s, so before the era of ten speed drive chains
Is this my problem?
Also - my chain did not come with the quicklink - it came with a chain pin
Unfortunately I removed too many links, installed it, and then had to break it, and add additional links
Since there was only one 7900 chainpin, I had to use older chainpins (7800?) to attach the additional links
The instructions for 7900 chain recommends that the chain not be broken where the 7900 chainpin is installed so the chain now has three chainpins - one 7900 and two 7800
Anyway I will probably start by installing the new KMC chain
I will also purchase some 7900 pins - should I also get a new chain tool for 10 speed chains? Any recommendations?
I am plenty happy with 10 gears - I am not sure we need to keep going to 11 , 12 13 etc
Good call on the new chain. Try to flex the joints where you broke and see if its as flexible as unbroken joints. Its very easy to not have the pin in all the way or just a tad too far.
Edit geeze i really need to pay attention to the dates on these posts. There goes my 2c down the drain
Actually, I used a Parktool chain tool from back in '94, when I first bought it. But its different for me as I used it only for breaking and not re-linking after moving to the 10-speed system. So its not an issue on my system as I use the KMC quick link. But I have attached 2 or 3 chains for friends using it on the 6700 mechanical system. But no issues to date were reported though. But of course, they were using the specific pins meant for the chain.
The pin and chains breaking part are standard actually for any chain.
Have had this happen. Shifts great everywhere except two middle rings. In those one would shift up and then back down on its own. Faster if under load like uphill. The other would just sometimes go back and forth. With adjustments I could move it up or down a cog, but two side by side shifted on their own. Fix was adding one more link though there was nothing 'wrong' about the length to start with. Added link, fine tuned the derailleur, everything good and smooth as silk.
This was on brand new 105 everything with a Ultegra chain.
sorry for bringing this thread up again, but it was the only one I found about Di2 problems - and I think now the problem is happening to me
history: 2 years old external wired DA Di2 installed on a Scott Addict R2
bike used almost daily, 30-80mi/day (depending on training schedule)
for the last 30 days I haven´t cleaned it up and the bb area (and wires) is very very very dirty (dry mud, it´s been raining sometimes)
2 days ago I noticed something was wrong, but it happened only 3-4 times and then stopped
but today the problem showed up frequently and I could replicate it at home
I thought it could be the battery, but I charged it and the problem is still there
here´s what´s happening:
everytime I shift the RD, it moves the chain to the next sprocket correctly - BUT after a few seconds, the junction box blinks red twice and then the derailleur moves by itself again in the direction I had shifted before (up or down) - causing another (unwanted) shift...
my RD is ghost shifting!!!
JB...sounds like operator error. You most likely have your RD in crash recovery mode. Read the Di2 instructions. When you push the button on the junction box the RD first goes into adjust mode. If you hold the button in longer it goes into recovery mode, shifting through the entire cassette.
To check charge you push any of the shift buttons until the battery indicator light comes on.
While the written directions are very clear, having that button on the junction box makes you think that it's the battery checker. Ask me how I know
thanks for the reply, Wheelman55
but it´s not operator error... it´s really deffective
i am an experienced user
it started happening once in a while, now it happens everytime i shift
when i do, some seconds later the light blinks red twice and shifts espontaneously one or two more cogs... either up or down
I'm having the same issue with "ghost shifting." I noticed a jump a couple times on a ride over the weekend. Last night it started really acting up exactly how you were explaining. I couldn't find any info on it. I called shimano and they said that I need to take it to my LBS and get it hooked up to the tester, that is, if they have it.
sounds like you need to find a shop w/ the Di2 diagnostic thing...that might be able to pinpoint the fault if there is one. or maybe call shimano and talk to someone in tech support.
What CXwrench said. The Di2 system checker will tell you which component is at fault. Bummer that it wasn't an easier fix. You'll need an LBS for this.
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