Am I missing something?

Signal_ rabbit

Okay I recently got a Cube Peloton Pro compact 2013 which is Tiagra throughout and a 10 speed. The rear cassette that came with it was a 12-30.
I wanted to change this so got another Tiagra cassette an 11-25 but it doesn't play nice when changing. I can fine tune it to work on the downshift but then drags its heels on the upshift. If I fine tune it on the upshift then it drags its heels on the downshift.
I also tried a 105 11-28 with the same results, so I took it all apart reset the rear derailleur stops and went at it again with the same results.
Am I missing something really obvious, have spent all day at it and I am left scratching my head?

Plastik

How old is the cable?

ROK ON

Could it be that your chain is to long for the new cassette.
Did you cut the links?

longshanks

Have you tried turning it off, then turning it back on again?

Muckers

+1 0n the chain. It's probably too long for the smaller ratio cassette.

Signal_ rabbit

@Plastik: the bike is only a couple of weeks old.
@Rok On: would I need to for a 105 11-28? its only slightly smaller than the cassette that came with it (12-30)?

ROK ON

I can't recall but it would be around 105 links.

Break the chain.
Remove from the rear derailleur.
Run the chain around the big front ring and largest rear sprocket.
Pull the chain tightly.
Now count the links and add one.

That is your cabin size.

bcmf

Plastik wrote: »

How old is the cable?

This.
When was the cables and housings last changed. Hesitant shifting is usually (but not always ) a result of sticky cables.

Signal_ rabbit

Okay tired shortening the chain and it makes no difference. If i shorten it too much the 11-28 wont fit

Plastik

Can you get it indexed properly again with the 12-30 that was on it?

victorcarrera

Check these also.
If there was a spacer on the inside of the existing cassette you probably have a 9/10 speed hub and you must use the spacer with the new cassette. Check that the cassette has no free play when the locknut is fully tight. If you have a 10 speed hub there is no need for the spacer.

Assuming the 12/30 cassette was working ok the B tension should have been adjusted to keep the pulley wheel clear of the 30 sprocket. Adjusting it closer to the 25 sprocket may improve shifting.

clog

have you adjusted the b-screw at the back you might need to screw it out a bit as it will be screwed in to accommodate the bigger cassette.

Signal_ rabbit

the 12-30 that was on it cannot be used as I took off a couple of links to accommodate the 11-28 so cannot check.
The B screw is adjusted correctly.
Cables and outers are new as bike was new when I bought it.

The same problem still occurs on the 11-28 and the 11-25.
As I said I can get it adjusted either up or down perfectly but then the other way needs a slight twist (less than a quarter turn) on the adjuster to make it work, then of course the opposite direction doesn't work.

bcmf

Not being smart but when did you get the bike? How often do you use it as in this weather its not uncommon for cables to be changed twice over the course of a winter especially a wet one.
Moisture gets in between the cables and housing's and stops the cables form sliding -hence you can get good shifting one way but not the other,

Plastik

Almost guaranteed to be a cable issue to be honest.

Darkglasses

bcmf wrote: »

Not being smart but when did you get the bike? How often do you use it as in this weather its not uncommon for cables to be changed twice over the course of a winter especially a wet one.
Moisture gets in between the cables and housing's and stops the cables form sliding -hence you can get good shifting one way but not the other,

The bike is a couple of weeks old, 6th post.

Signal_ rabbit

Okay took out the cable, lubed and put back together.... same problem.

The only thing I can think of is the 105 is not compatible (but should be) but that doesn't explain why the 11-25 doesn't work.

I don't think its mechanical more like a compatibility issue?

bcmf

Darkglasses wrote: »

The bike is a couple of weeks old, 6th post.

Ah the whole 'reading every post' thing has kicked me in the arse again.

seve65

all unlikely given its a new bike but:
1. worn out spring in the dr
2. small bend in the cable at the shifter end
3. derailleur hanger not aligned
4. poor cable routing into the derailleur cable clamp
5. see if you can wiggle the cassette in any way

Personally, I have found clean cables have fixed most of my problems on my not new bike

Signal_ rabbit

I have tried a different derailleur, changed the cable and tried a third cassette. It works about 98 % of the time(ish), I have come to the conclusion that it is just Tiagra shifting and its not as precise as what I am used to as it needs a bit of coaxing from time to time!