Dreww10

My R8000 Di2 setup was more or less perfectly tuned when purchased. I noticed in the first few months the chain started falling off the largest sprocket (30T) onto the 28T under load, but in recent weeks, the bike stopped shifting into the 11T. It basically clickety-clacks when I try to shift over, much like a mechanical cable being too tight would. This bike has never been crashed, bumped against the wall, knocked over, or anything, so unless pedaling forces alone can bend a derailleur hanger, there is no reason it would be bent. I've had a bent hanger before and know what they look like, and this one is arrow straight. I have made some small and large micro adjustments in each direction, and it doesn't cure the issue on either end of the cassette.

Can Di2 go haywire and not know where the cogs are? Can it be reset? I'm relatively comfortable with adjusting limit screws, but I'm leery of toying with them and really getting it jacked up.

ckmak

Have you logged into etube to check what cassette you have selected? Not sure if that can effect it.

Also you might want to go into adjustment mode to adjust the rear mech. Have a quick google and you will find a few videos on it.

Le Mechanic

You may or may not be aware, but by default, Di2 is programmed to not allow the rear derailleur to shift into the 2 smallest cogs while in the small chainring up front.

Iride01 

The other issues you are having with your drive train might suggests something more that just Di2 derailleur issues. Have you called the bikes shops around your area and confirmed if they are working on bikes or not?

Le Mechanic is correct. My version of Di2 R8050 has that limitation. I don't know if all versions are limited.

ckmak

Yes completely forgot about that as well.

Dreww10

This is in the big ring.

Dreww10

I don't believe I have access to that without buying the extra bluetooth-enable part, right?

Steve B.

Download the E-Tube software from Shimano - Windows only, then use the charger unit and cables, plug to a USB port on the computer, and into the charging port on the A Junction. Then launch E-Tube. You can collect and configure this way.

melikebikey35

What cassette you are running is irrelevant, unless you have it set up so that your gear selection is displayed on your computer. It has no bearing how the RD shifts.

It it very much sounds like a limite screw issue...but it could also be a worn chain...or a combination of the two.
If the chain has a decent amount of miles on it, I'd start by replacing it. Then go on to the limit screws if the problem remains.

bbbean 

If microadjustments using Di2 don't resolve the problem, my money is on set screw.
BB

bbbean 

If microadjustments using Di2 don't resolve the problem, my money is on set screw.
BB

Dreww10

Other than a bent hanger, limit screws should never go out of adjustment, right?

August West

Correct. Unless something happened like an accident the limit screws shouldn't ever need to be touched assuming they were adjusted correctly when it was initially setup. And since you are having issues at both the top and bottom of the cassette it doesn't sound like the limit screws to me.

How many miles? You stated this started happening a few months it is still pretty new.

I would try to do a crash recovery on it by pressing the junction box button for more than 5 seconds. It will shift through all the gears so you need to be spinning the crank when you do this to keep it from binding up. Not sure if it will help but it won't hurt it.

Have you checked that everything is tight - like the cassette lock ring?

melikebikey35

In theory, no, they shouldn't go out of adjustment...if properly set up in the first place. And I have a feeling they weren't.
Another issue (especially at the larger end of the cassette), can be the B-Limit screw. If it's too close to the sprockets, it can cause grinding and interfere with shifting...did you replace the original cassette with a larger one?

bbbean 

"Shouldn't" and "don't" are two different words. Very easy to check and adjust.

BB

GeneO 

After some hundreds of miles riding I had mine go out of adjustment, nearly resulting in a dropped chain. I was surprised.

Bmach

Sounds like something might have “bumped” the derailleur..

Dreww10

This bike has so few miles and babied so much, nothing would have bumped it without my knowledge. I did get it to shift into the 11T, but I had to make a fairly considerable change to the high limit screw to get it there. Not sure what to do on the 30T end, because it shifts into the gear just fine, but falls off under load...if I tinker with the low limit, it might start tossing the chain into the spokes.

MugenSi

I would screw in all the limit screws and start the set up process from the start.

bbbean 

Settings sometimes change mysteriously. Things happen you're not aware of. Since you're having a problem, SOMETHING happened, whether it was an accident, electronic corruption, fatigued components, or LBG (Little Bike Gremlins - they crawl around your bike in the middle of teh night changing things for no reason). Crux of the matter s that it isn't shifting like you want it to.

FWIW, the suggestion to go back and reset it from scratch is a good one. I recently did that on my road bike when I had a similar issue. 20 minutes of tweaking and it shifted like new, and still does a few thousand miles later.

BB

Steve B.

Screwing IN the limit screws prevents the derailer from getting anywhere near its limit. You usually unscrew - I.E. back off the limits to get the derailer onto it’s appropriate cog. Then you tighten the limits while watching the derailer until the jockey wheels are lined up directly with the cog teeth, or you feel the screw engage the derailer stop. Shimano states it this way.

Steve B.