Ultegra Di2 front derailleur shifting problem

Equipment
1

I’ve started to see poor shifting with my front derailleur (Ultegra Di2 12-speed R8150) shifting from the small to big ring. Not all the time, but enough to start bugging me. I can generally get it to shift, by dropping a gear at the back and then shifting front derailleur again.

Everything had worked fine for a year, and limits should be set up correctly. Problem only started the last month or so.

Any ideas on what to look at first? Or should I treat it as if I’m starting setup from scratch?

Thanks for any advice.

2

Have you replaced chain recently? How many miles on chainrings?

3

About 6000km on the chainrings. Two waxed chains used in rotation since new, so minimal wear.

4

It doesn’t take long to do the set up “from scratch” so I would try that if there aren’t obvious signs of wear to any of the components.

2 Likes
5

My ultegra DI2 does the same thing with a freshly waxed chain, after a couple miles it works flawlessly.

6

It happens with chains that are “bedded in” so I suspect it’s not that, but I’ll keep an eye on it.

7

Have you had the cranks out at all?

I’m on the 11sp 8050 so went into the shop for the recall inspection. The shop somehow managed to not get the crank all the way back in when replacing, and it mostly felt fine, but the small alignment difference caused issues until I realised what had happened.

8

Check the support screw. Maybe it loosened out.

9

Hello! I am having exactly the same problem on a Shimano Ultra R8150. Right after turning on the shifting system pushing the bottom of the rear derellieur once, the shifting of the front derelliueur works just fine (I can shift up and down multiple times without problems). However, in the middle of a ride, it can happen that I can not shift anymore from the small to the big chainring (from big to small always works well). I usually get it to work after many times. I did a firmware update of front and rear derailleur but it did not solve the problem. I use waxed chains and change then every 300km, the problem does not seem related to them. Do you think it may be a misalignment of the skid plate? Anyone who solved the problem?

10

any chance the cage got dinged and its bent a hair? Ive had that happen and your symptoms sound identical. If not, id just start fresh. move the adjuster to 0 and follow the startup guide from the app. If that doesnt work, its time for a trip to the shop

11

Finally got the chance to take a look yesterday, took the derailleur off and started setup from scratch again. Shifting fine in the stand, but still intermittent issues during this mornings ride. Will probably live with it until it bugs me enough to take to the bike shop.

12

This might be worth looking at: