R8050 Di2 RD H-limit not enough adjustment
 

Hi!

My TCR has some Di2 problems. RD does not have enough H-limit adjustment to make the pulley align with the smallest cog (11t). With the H-limit screw all the way out, the RD ends up between the two smallest cogs.
I have to use micro-adjust to compensate for this- which I asume is not ideal, considering ur suppose to have 16 clicks in each direction, X/Y. 32 Total. I've tried crash mode "reset", disable stuff with e-tube etc.
D-Hanger is nice and straight. Btw, I'm not able to run diagnostics with the SM-BCR2 charger.

Any ideas?
Thanks!

Derailer is not installed on the drop out correctly ? Have a shop look at it ?. Do a temp install of a mechanical derailer to see if you get the same issue. You will know right away if the jockey wheels dont sit under the smallest cog that the issue is the frame/dropout.

Why can't you run diagnostics with the SMBCR2? Or are you talking about the in depth stuff the other unit provides?

If you can't get in to see the components with the SMBCR2 then how do you even know it is shifted to what it thinks is the 11 cog. Though I guess you could shift all the way to 1st and then count.

You cant run diagnostics at all with SMBCR2 it seems like? Must have the other units.
I installed the older E-tube 3.4.5 version, which seems to be alot better then 4.0.4...

RD is mounted correctly. I only have vintage RD's available, is that ok to test? :D

Will take bike to shop on monday ofc... But id like to have a ride tomorrow :(

The hanger may look OK to the eye but if it is even slightly off it can cause the issue you described. Best to put an alignment gauge on to check if the hanger is properly aligned.

I can admit that ive only eyed the hanger, using a allen key and smallest sprocket as reference. Still... even if its slightly bent, it should possible to adjust the H-limit till its past the smallest cog?

Have you faithfully followed all the instructions in the Shimano DM for the R8050? https://si.shimano.com/api/publish/s...050-04-ENG.pdf

I couldn't make heads or tails out of your reply. There is only one version of the SMBCR2. I also only use eTube v3.4.5. If it can't identify all your Di2 components when connected, then you probably should not go riding with it tomorrow unless you are okay with buying another if you screw it up.

And what are you calling the high limit on a Di2 RDR? There isn't a high limit screw you adjust with a screwdriver AFAIK.

I'm sry, english is not my native language.

Top-side stopper bolt is what I mean by H-limit, same same? :D

eTube does identify all my components, but does not allow to check for error. As you said, I need extra parts for that

Do you really need that smallest Cog?

^ No, good point!

If it is a carbon frame check out the support bolt is not pushed in too far.

Look at the manual here on page 39.

Please disregard what I wrote above. I was working on my own front 8050 and it was in my mind and certainly didn't read the thread correctly. Thanks to CXWrench the "self proclaimed" #promechaniclife for pointing this out so eloquently. Now back to working on my brifters, they seem misaligned on the bars.

You may have an extra spacer under the cassette.

Good idea, that would certainly do it.

Tgat was my first thought. If the chain is shifting fine on the first 10 cogs, then the last one may be just too far outboard.

How does that change where the smallest sprocket is in relation to the derailleur?

No, you'd have to have a massively bent hanger for it to make that much difference at the small cog end. It's the large cog end where a small hanger alignment issue will cause a problem.

You haven't read much of this thread, have you? The OP is having REAR derailleur issues, not front.

For the OP...take it to a shop and have them plug it in. The shift adjustment may be way off in the wrong direction. Or you can just adjust the crap out of it and see what happens. I've never seen this happen.

It should not be adjusted way off. There's 16 steps inwards/outwards, its -4. If I let the L and T-stoppers all the way out, should it now allow full range of movement?

Thanks for help so far! Looks like taking it to a shop is the only way

Update:
I took the cassette off. No spacers. However, it seems to be some play in the cassette and/or freehub. Its Giant SLR wheelset which I believe is basicly DT Swiss hubs rebranded?
How on earth do you remove play on these? The freehub is just pushed on? I guess the bearings inside the freehub might be bad

If you can't find the issue, you can just kludge it with a washer under the derailer mount bolt.

Moves the entire cassette outboard. Even with the high limit screw wide open, the detailer won't position under the smallest cog.

Thats a good idea too!

It seems like ive might managed to fix the problem.
I originally used eTube 4.0.4, which does not allow you to do much, except shifting mode adjustments. You cant even choose multi-shifting speed higher then "normal". Who did they relase this software version for?
So I installed eTube 3.4.5, and adjusted everything again. For some strange reason it seems to might have fixed it. @Iride01 might be right that there has been an issue with which gear it thought it was in. I will take it to the shop just to get it confirmed, and to see if they can fix my freehub, and buy a new cassette.

I should have asked this right off. Are you talking about an inability to shift to the 2 smallest cogs WHILE IN THE SMALL CHAINRING ?. If so, thats normal Shimano. Di2 normally locks out those 2 cogs in that chainring. Its Shimano essentially saying you dont need that combo, its available on a big ring using their cogs.

^ No. Only smallest cog, the 11th gear, or 11t cog if u like :)

In the shimano user's manual, it says to shift from biggest cog, down to 5th cog, small chain ring. Adjust till you hear audible noise from rubbing 4th cog. Then 4 clicks outwards (towards the smaller cogs). Whats the point of having 36 steps? And it doesnt specify, but I asume they want you to start from micro-adjust position 0?
Its 18 steps each direction.

I just joined this forum in order to share what I learned about this problem, in my case at least. I have a 2020 Cannondale Supersix. The only way it shifted properly was to have the Di2 rear deraileur adjustment all the way to the outboard side (+16 clicks). Even though it shifted fine like that, it bothered me because if something needed adjustment on the road, I might be out of luck.

After reading all I could find about this problem, I added a washer between the hanger and the deraileur, as others have suggested. It didn't buy me much, if anything. I then tried bending the deraileur hanger (removed from the bike and placed in a vice). I hit it with a plastic, sand filled hammer to try and bend it. Even though it would seem like I moved it a bit, after I put it back on the bike, it I didn't bend it at all. I tried this several times with the same result. That deraileur hanger is surprising rigid. Obviously I could hit it hard enough to eventually bend it, but I wasn't sure that was the best thing to do.

I kept examining and thinking about the problem and eventually realized something: the part of the bike frame that the deraileur hanger mounts to was actually just slightly angled inward. It is extremely subtle and hard to see, but it is slightly angled and not entirely vertical.

So, I meticulously cut a shim out of thin aluminum to place between the frame and the hanger. I cut it carefully so that it matches the outline of the hanger. Then I sanded the shim on an angle to make up for the incorrect angle of the mating surface of the bike frame. Assembled, the upper limit of the shim is thinner than the lower limit of the shim. This negated the slight angle of the bike frame mounting surface. Hope this make sense.

After reassembly and and adjustment I was able to electronically adjust the Di2 rear deraileur 5 or 6 clicks inboard! I had solved the problem. I was always dubious that the issue would be on shimano's end, and I was correct. The problem was with the bike frame.

Hope this helps some folks. If my description is clear as mud, please reach out and I'll try to explain better or maybe post some pics.

They make a tool to straighten hangars. Sounds like you needed one...