Di2 problems.

ben@31

Q1. Im having trouble indexing the Ultegra Di2 rear derailleur. Its not shifting into the smallest sprocket (11t) at all, regardless of limit screws or maximum adjustment and when indexing I can only get some gears in index but others remain out, then you then end up chasing your tail. On the road when I try to change gear it requires two presses off the button to get it to change down from the biggest sprocket down to the next. Or sometimes when shifting you can hear the chain will be slightly out so another press of the button will seat the chain properly, or shifting down past the required gear then shifting back up again.
Yes I have replaced the rear hangar and even the derailleur cage. The previous week I replaced a worn chain and cassette.
A LBS had a quick look as I was passing by and reckoned the Di2 is missing out a sprocket, like its shifting for 10 speed rather than 11 speed and wondered if its worth plugging into the diagnostic tool and re-installing firmware. Any ideas?

Q2.If I change frames and keep the groupset (if I get it to work again). What do I need to change from an external Di2 fit to internal routing ? Do I need to change cables? Will the junction boxes still be the same? I might keep the battery I have now under the bottom bracket or buy an internal one for the seatpost.

Thanks.

ugo.santalucia

Is it a Di2 problem or a 11 T problem? My mechanical gears are perfectly set up but getting out of the 11 T and onto the 12 T it's not straightforward... I think it's the teeth design for the 11T sprocket

ben@31

Ugo... It worked perfectly before for years and only started to play up now. I replaced the cassette like for like, its even the Ultegra 6800 cassette not an aftermarket one. The derailleur isn't moving anywhere near the lowest / smallest sprocket.

pilot_pete

ben@31 wrote:

...wondered if its worth plugging into the diagnostic tool and re-installing firmware. Any ideas?

That would be my first port of call.

PP

meanredspider

You've changed the hanger but have you checked alignment? Start with the simple things first and the symptoms you describe are what I'd expect from a misaligned derailleur. I'd be very very surprised if this was a firmware issue - especially if nothing has changed.

Going internal only really needs a different BB junction box (you could leave the same one and leave it inside). Wrap a few fine tie wraps around the cables to mimic what Shimano do on their cables to stop them rattling in the frame. External battery is best in my view.

06dhewett

Assuming you do actually have an 11 speed rear derailleur, you should check the hanger alignment of the new hanger you have installed. It cannot be assumed that a brand new hanger will not require adjustment by bending once installed on the frame. Also check the integrity of the new chain you have fitted, ensure there are no stiff links or similar. Obviously wind the limit screws all the way out to begin with.

ben@31

meanredspider wrote:

Going internal only really needs a different BB junction box (you could leave the same one and leave it inside). Wrap a few fine tie wraps around the cables to mimic what Shimano do on their cables to stop them rattling in the frame. External battery is best in my view.

Im I correct in thinking the cables are the same, its just the bottom bracket junction box thats different?
I noticed a Trek Domane in the LBS had internal DI2 cables but the external battery hung underneath the bottom bracket. Maybe the internal battery won't fit in their flexing seatpost ? I dont "plan" to cycle in the rain so if this is a reliable place for the battery I might go for that set up (mines currently by the bottle cage). It would mean I only need to buy a new junction box.
Thanks.

06dhewett

ben@31 wrote:

Im I correct in thinking the cables are the same, its just the bottom bracket junction box thats different?
I noticed a Trek Domane in the LBS had internal DI2 cables but the external battery hung underneath the bottom bracket. Maybe the internal battery won't fit in their flexing seatpost ? I dont "plan" to cycle in the rain so if this is a reliable place for the battery I might go for that set up (mines currently by the bottle cage). It would mean I only need to buy a new junction box.
Thanks.

The external junction box can be used internally without issue. My previous bike had an externally mounted battery on the underside of the NDS chain stay, just behind the bottom bracket, and it failed due to corrosion of the contacts. Pretty terrible place to put electronics in my opinion as if the road is wet the spray from the front wheel is directed straight at the battery and the electrical contacts.