I bought the RD-R8000GS (medium cage) a couple of months ago because I thought my RD cage was bent, and I also wanted to run bigger cassettes, and my RD hanger was not bent, so had to give it a try.
The rest is ST-6870 groupset with the SM-EW90 ans SM-BTR1 battery.
The RD dont want to move all the way out or in. It wont slightly overshift into the smallest cog even if the limit screw is all the way out. It wont shift properly up the cassette either. When it comes to the largest cog (32t) it wants to shift another gear up, wich means chain going over the top and into the wheel. When the H limit screw is set properly to not overshift on the 32t, the RD just tries and tries until it gives up shifting and shifts back half a cog. The microadjustments is set to 0 (16).
So I cant move the RD properly down the cassette it seems like. If i set the microadjusts to maximum the 11t is ok, but not the rest, since the H limit is not OK. Tried to hold the button on the SM-EW90 and let the gears cycle through, since its the only function part from the microadjusts I belive.
Visited the local shop (not a proper shop, a "we have everything and its cheap", so dont trust the mechanichs there that much, but I asked them to upgrade mye firmware, and it did not return any error codes either. The e-tube chart I think say my battery is not compatible but, the problems was there on the RD-6870 too.
Any ideas?? Thanks
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