[Sandwich]

10 speed setup
Full length housing
Weird FSA shifters: https://www.amazon.com/Vision-Metron-Speed-Alloy-Shifter/product-reviews/B005VZW19C
Ultegra 6800 rear derailleur
SRAM PG-1070 11-23 cassette
XTR 7900 Front
36-52 rings
KMC X10 Chain

Problem:
I seem to be able to get great shifting at the top or at the bottom of the cassette. If I tune to have good shifting in the small cogs, when I shift to the top, I need to start adding additional lever pull after the click in order to move the chain to the next cog. If i tune to upshift well, I lose the ability to get into the smaller gears due to cable tension. So, my shifting remains sloppy and requires additional manipulation to get across the cassette. Shifting also seems to be chainring sensitive, with better or worse shifting depending on what ring you are in.

I just replaced the housing which seems to have helped but not resolved the issue. Downshifting into low cogs is quick and snappy when tuned "correctly" likely indicating it's not the cable. Cage appears straight, hanger was new and appears straight. Shifters and derailleur SHOULD be compatible (ie not a cable pull issue).

I'm a little stumped here. Happy to provide photos if it will help.

 

[Jm_]

Is there any weird FSA cassette you could run?

 

[Westy]

Sounds like you need some Campy components in the mix

 

[jonKranked]

top comment on that amazon link indicates higher than normal cable tension is needed?

 

[Sandwich]

top comment on that amazon link indicates higher than normal cable tension is needed?

Yeah, that was why I swapped the housing. I guess I should try the cable too, as shimanos are pretty slick. I seem to be able to get pretty close, just a little off on the upper two cogs. Haven't tried any other shifters on this frame, but the cogset and wheels were bolt action on the other bike (with other shifters).

 

[jonKranked]

chain stretch? just trying to rule things out

 

[Westy]

Poorly setup b-screw can lead to good shifting on one end of the cassette and poor shifting on the other.

 

[OGRipper]

^This is strange but true. For me it more typically happens when something is bent or out of alignment. You can also get it when the spacing is close but not quite right between shifter and cassette, which can happen with Frankensystems and cheaper stuff.

In any case, yeah, it's worth changing the cable to eliminate that as the culprit.

Binding derailleur parallelogram pivots could do this too, so make sure they're lubed up and moving freely.

 

[slimshady]

Have you checked your derailleur hanger's alignment? Mid-cassete odd shifts are usually caused by a badly aligned derailleur hanger.

 

[Sandwich]

Kind of- I can eyeball it and it looks good. I checked with a yardstick and it seems good. The lower cage of the derailleur seems to have an outward/small cog dogleg to it, but that seems to be true in images found of 6800 derailleurs found on the innernet. I have not checked with a shop tool.

I loosened/reduced B tension all the way and have good shifting in the small ring but slightly mediocre in the larger one. Livable for sure but still trying to get to 100%. May just need further re-indexing in the large ring.

 

[Jm_]

Shifter determines the cable pull. There's a lot that can be going on, from sloppy derailleur, to bent derailleur, to bent hangar, wrong b-tension, and so on. But if that shifter doesn't pull the right amount for that cassette spacing, then it'll never work, just like the bar-bike I set up with an 11spd shifter, derailleur and 10spd cassette, because fuck thieves. But even if it's 10spd and 10spd, it doesn't guarantee that the 10spd spacing of that cassette is the same as FSAs shifter. No matter what they say, after you've eliminated the other variables, it's likely the shifter.

For reference, I recently "upgraded" to a "12spd" Eagle X01 derailleur on my Canfield, but I'm running 11spd cassette, chain and shifter. It works brilliantly. It works because the shifter determines the cable pull (with a few exceptions). Something about the Canfield's derailleur hangar location couldn't deal with the range of the E13 cassette, despite me running the same exact config on two other bikes...I chalk it up to the hangar location relative to the dropout and I figured I needed a derailleur with more range capacity. Rather than buy the pricy garbaruk extended and oversize pully/hangar system, I just went ahead and bought a 12spd, more future-proof and better to start with a fresh derailleur. Again, works great and it was the right choice. Even took someone on a ride yesterday and let them borrow this bike...which you kinda don't want to do when you know your shifting or bike is all janky and doing something that only you can put up with.

 

[Sandwich]

So I bribed woody with a kids' bike to see if he could tune them up. He shook a fist and gave up. Said the cable was slick and everything was straight, so it's either compatibility or time to start replacing shit.

I ended up giving a test run to my free derailleur pulley courtesy of alibaba himself and it honestly may have fixed things. Seems to be working a bit better with less lag on the big side of the cogset. Need to road test as that's the real measure, but it works in the stand.

Too bad I just ordered a cassette and freehub, but I guess those can wait in a box for the time being.