Hive Mind: Busted ST-R8000 shifter

[reuben]

Right shifter.

As near as I can tell after partial disassembly, the wheel/cam that grabs the cable is about 180 degrees from where it should be to thread a shift cable through it. I can see the part that looks like it should grab the head of the cable on the inside (stem) side of the shifter after peeling the hood back, removing the lower plate, etc. So, yeah, about 180 degrees from where it should be.

Without sailing into uncharted waters and disassembling the thing further, likely increasing my frustration level and alcohol consumption, is there a way to fix this?

[tctyres]

Maybe.
How did it get like this? Did the cable shred in the lever, and then you pulled it out?

All you might need to do is get it to click "back" so that the threading hole is aligned with the cable stop holder. To get it back, you need to figure out how to put tension on that wheel (the white teflon-looking one) and then click it back.

I recommend good lighting, small tools, and scotch.

[reuben]

New build. Installed most everything, including cables, got them close. After verifying chain length, I removed the chain to take a good cut at the derailleurs. Noticed that rear derailleur was stuck, would not shift in either direction. Found no mechanical blockages in back. Made my way to the front and found that the cable was not moving when I pressed either shift lever. Peeled back hood, removed cable. Cable looks clean and fine. Put it back in. The cable still didn't move. Consulted the manual, and, of course, youtube. No real help. Took the bottom plate off looking for anything odd. Saw the wheel/cam with the slot for the cable head facing me on the inside of the lever. This struck me as incorrect.

No idea how it got into this position, but I'm pretty sure it's the root of all evil.

Even with no cable at all it's rare for either shift lever to actually click and move the wheel. I suspect that it's gone past some sort of limit and can't get back (to where it once belonged).

I have mediocre lighting, although I keep a very small but bright flashlight in the bicycle tool chest for just this reason (darn shadows). I have a variety of small tools, but probably not the right one(s). A sawzall seems to be overkill, but it's tempting. No scotch, only beer.

[dddd]

I've had to help the wheel along using a tiny screwdriver or pick, one click at a time.

Then, with the cable hook aligned so you can insert the cable, perhaps then the shifter will work normally with some cable tension on it(?).

[tctyres]

OK. It got like this because someone clicked those levers before there was a cable in the right position.

You need to get it to click it back to the "down" (ie no tension, small cog) position with the cable stop aligned with the hole in the black plastic housing.

What dddd says is one way to do it. If you push on the wheel with small tools and click down, it will work its way to the proper position. Then, you can re-thread the cable and Robert is your mother's brother.

Getting that stop back is super frustrating (just so you know!). I did this with a 6800 shifter that did have the cable shred in the lever. You might want to take the brifter off the handlebars to do it.

[reuben]

I think that you and dddd have me back on the straight and narrow. That seems to have moved the wheel into the proper position - it matches the left 2x shifter, which works fine.

I might have boogered it myself - I had a colonoscopy this morning, and even though that's just minor anesthesia, maybe I shouldn't have been fiddling with a bike when I got home.

:eek: :no: :crap: :rolleyes:

So double check me on the next steps:

1) Adjust high and low screws on RD so that they line up below the small and large cogs (done).

2) Thread and clamp cable with RD on smallest cog.

3) Install chain.

4) Shift up and down a few times to seat everything.

5) Make fine high/low adjustments.

6) Make B screw adjustment.

[tctyres]

That's right.

Just some notes:

3) On chain installation, make sure the chain laces around the lower jockey wheel inside of the outer lower part of the cage and on the correct side of the support between the jockey wheels. The chain will make a metal-on-metal noise if you didn't do this right. (Yes, I've done this at least once, and not often.)

and

5) On fine adjustment, there is a way to make sure the cable won't shred or break in the brifter, but the link on how to do it escapes me (there is a way, though). Make sure the chain doesn't go into the spokes, even when you pedal. If you can, set up the bike in a stationary trainer to go through the shifting under load.

6) The B-screw should only matter with the chain in the largest rear cog.

[dddd]

That's right.

Just some notes: ...

5) On fine adjustment, there is a way to make sure the cable won't shred or break in the brifter, but the link on how to do it escapes me (there is a way, though)...

I think that this would be always visiting the lo-limit screw on the rear derailer after the cable adjustment is done.
This is so that the cable is not seeing any peak of tension force upon shifting onto the largest cog, which is what I believe causes the cables to fatigue prematurely inside of the shifter.
I.e. making sure that the lo-limit screw is not set too tight.

[Ozz]

...
I have mediocre lighting, although I keep a very small but bright flashlight in the bicycle tool chest for just this reason (darn shadows). .....
Dude....working in tight spaces and need free hands...use a headlamp (https://www.homedepot.com/p/Coast-500-Lumens-Tri-Color-Focusing-LED-Headlamp-2-Pack-FL74/305286190)!

[reuben]

Dude....working in tight spaces and need free hands...use a headlamp (https://www.homedepot.com/p/Coast-500-Lumens-Tri-Color-Focusing-LED-Headlamp-2-Pack-FL74/305286190)!

Thanks, I have a BD headlamp for backpacking.