Hi all,
I’ve got the 7900 series dura ace di2 10speed set up and the last month the rear derailliuer has started randomly dropping 3 gears for one shift??? It appears that the both lights sometimes flash when it happens. It also sometimes stops and won’t shift at all and I have to leave it in the same gear for a minute or 2 then it seems to shift? I took it to the lbs (which is in Thailand as in racing overseas at the moment) and after they played with it I had no rear deraillier at all. I realised that the shop had obviously forced it around and put it into safety mode. I managed to reset and fix this but now it’s shifting the entire cassette on 1 single press… What is going on with it??? Im also under the impression you can’t even replace these now?? Does anyone work at a shop and have witnessed this before?? Ive tried everything and come to a dead end
Did anything happen to the bike just before the malfunction? If so start there. Sounds like the shifter button is sticking or stuck. The derailleur will only do what it is told it doesn’t have a brain of its own. Did you know you can reprogram the system to make the shifters work differently? Reprogram it, if that doesn’t work swap shifters. Troubleshoot single items at a time so you know what fixes it. Then tell the rest of us what it is.
Thanks