Mattyb13

2017 Specialized Diverge Carbon.
Praxis 50/34 up front. I upgraded to 50/34 from the 48/32 that came stock with the bike.
Shimano 105 Group Set.
11/32 stock cassette.
Original stock Shimano 11sp chain. Never lengthened or shortened.
Shifting was crisp and dialed with the above setup. No issues.

I just upgraded to an Ultegra 11/28 cassette. Self install. Install went flawless. However my shifting is now off and Im not sure why or what to do?
1. The shifting seemed a little lazy upon first try with the new cassette.
2. I can not shift across all of my rear gears. Staying just in the 50 up front and Using the barrell adjuster I can shift all the way down into the lowest gear, or all the way up into the highest gear but I can not do both. I have to do one or the other. If i tighten the barrell adjuster down clockwise I can find the lowest/smallest gear. If I back the barrell adjuster off counter clockwise I can find the highest/largest rear gear. I know you never want to be all the way in the highest gear out back and the biggest gear up front but with my stock cassette the bike would shift flawlessly across the spectrum, and now clearly I have affected the shifting with the new cassette. I would love any advice, tips etc. I am not against bringing it to my local shop but I love learning about this stuff, and if its something easy I can do then I want to try! Thanks all!

Homebrew01

Is the Ultegra cassette slightly inboard, or outboard on the hub, compared to the 105 ?
If so, tweaking the adjuster should fix it.
Does either have a spacer that goes on first ?

ThermionicScott 

Maybe replace the 2-year-old chain?

Dean V

Why is changing the gearing an "upgrade"?

colnago62

Ultegra Cassette

eflayer

less teeth on the new cassette and smaller chainrings would equal shortening the chain in my way of thinking.

UmneyDurak

Year, pretty much this.

Unca_Sam

+1, size the new chain without relying on the old chain using the large-large method.
I would have imagined that adding teeth to your chainrings would have caused shifting problems, so I'm not certain that reducing your low gears on the cassette would have completely offset that change. To be safe, just replace the chain and size it as appropriate, and then check your derailleur alignment front and rear.

caloso

My thought too.

Mattyb13

Ready to go get a fresh chain. Any chain suggestions? I know I need an 11 speed chain. Beyond that I am not sure what I want to buy. Thanks!

jadocs

I think there is more going on than just needing a new chain.

If you want a chain recommendation, I use Connex chains exclusively.

Succhia Ruota

A few things I would do in this situation:

1. As others have mentioned, replacing the chain is a good idea with a new cassette.
2. Make sure the chain is sized correctly for the new 50 front 28 rear combination. Plenty of videos online on how to do this. The one from @Unca_Sam is a good. You've changed gearing now a few times without resizing the chain. That will effect shifting performance.
3. Before you put the new chain on, disconnect the cable from the RD and reset the high & low limits. Then reindex the gears.

.

Edit: If you do all the above things and shifting is still problematic, I would look into having your RD hanger realigned.

Succhia Ruota

​​​​​​​I would just buy a standard Shimano chain.

Psimet2001 

As others pointed out you need a new chain in general. Outside of that just go through and set up the rear derailleur from scratch. Super easy and quick to do.

Put the new chain on (honestly screw the big big method just loop it over the small small and take enough links out to ensure the rear derailleur has some tension on it and then you can run any cassette that rear derailleur can wrap).

Shift the shifter all the way into the smallest cog setting on the shifter. Disconnect the cable on the rear derailleur. Set your H limit. Run the barrel adjuster all the way in and then back it out about 2 turns. Then pull the cable tight and re-anchor it.

Shift it one gear up. If it doesn't go immediately - like it hesitates then go back down and unscrew the barel adjust slightly and try again. Keep going back and forth until it's crisp and quick.

Shift all the way up the cassette being careful going into the largest cog. If you are stopped on the way up then you have the L limit too far in, there is a problem with the cable or housing binding or hanging up, you didn't have the shifter shifted all the way down when you attached the cable, or there is possibly a problem with the shifter. Go into the largest cog. Adjust the L limit so that if you push hard on the shifter the chain won't try and jump over the back of the cassette.

Now go up and down the cassette and every shift should be good. If not then you may have some cable friction or a hanger alignment issue, or you simply need to adjust the barrel again. In order to know which way to adjust simply leave it in the gear that is ticking a bit. While pedaling it push the body of the derailleur inward slightly with light pressure. If that helps improve the sound then you need more tension on the cable - unscrew the barrel. Of it gets worse then try pulling the body of the derailleur cage towards you (flexing) slightly and if that makes it marginally better then you need to release some tension. Screw the barrel in.

As for "why"? there are too many variables to address in a single post. Grab your cogs and make sure that there is no movement. Sometimes the 11t cog can get hung up or mis-clock as you are tightening the lockring. I have seen it happen to mechanics who have been doing this for 20+ years. If the lockring is tight and there is no movement in any of the cogs (wiggle back and forth towards each pedal side) then it could be the spacing of the hub, the cassette, is there a shim needed on your wheelset or did the cassette come with a shim, etc. Outside of all of that sometime you have to adjust the barrel slightly between cassettes. *shrug*