Shifting problems at both ends of the cassette

[Twilkes]

New cassette, new chain, new rear cable (inner and outer) but if I'm on the biggest sprocket it's reluctant to shift down to the next sprocket, and if I'm on the smallest sprocket it's reluctant to shift up to the next sprocket. So it doesn't seem like a derailleur alignment issue, and the derailleur and jockey wheels look straight to me, certainly no obvious bend.

Could the derailleur not be moving freely enough, i.e. it's gunked up and doesn't quite spring back to where it should be? I've zapped the moving parts with GT85 but it's been through a Scottish winter so may be suffering.

Or the other thing I can think of, previously I had 106 links in the chain, and it felt slightly too snug when it was in big-big, but that is a 50/32 gear and I would never use that gear, would always shift into the small ring much before that, so it worked fine. But I measured/calculated it properly this time as 108 links, and I'm wondering if there isn't quite enough tension on the chain for smooth shifting. Is there a practical test I can do to the chain to see whether there is too much slack in it? I've had some chain skipping when in a small/smallish gear but I initially put that down to the derailleur not being properly aligned, maybe it was actually low chain tension. And now that I remember it there seems to be chain noise from it bouncing off the front derailleur in the smaller sprockets which I never had before.

(the cassette was originally 12-28, for which the correct chain length is 106 links; switched up to 12-32 but kept the same derailleur, wondering if sizing the chain for that 32t sprocket is causing problems in the other gear combinations)

 

[T4tomo]

I reckon you have 2 problems going on here. too little chain tension is causing the problems on the small sprocket, dial in you cable tension a 1/4 turn at a time (anti clock) to fix it.
the reluctance to drop off big sprocket is probably a stiff cable. Before doing above step, undo the cable and see if the inner moves freely within the outer. If it been through a wet Scottish winter I'd replace the cable, then re index the mech - look at park tools video on You-tube of setting it up correctly, Limit screws and cable tension.

Chain is better slightly tight than too slack, but not so tight you cant accidently run big big. you can test this by overlapping the links with your hands and see if a link or two out will work.

if your chain is worn that could also cause the skipping so a new one might not go amiss. better to change it a bit early and not wear your sprockets by leaving it too long.

 

[Twilkes]

It's a new chain and cabling but the rest of the points are useful, I'll go through those on the bike. I was nervous about taking another link out of the chain but it worked last time so I may well end up doing that.

 

[Blue Hills]

It's a new chain and cabling but the rest of the points are useful, I'll go through those on the bike. I was nervous about taking another link out of the chain but it worked last time so I may well end up doing that.

I wouldn't extract links from a chain willy nilly as some sort of experimental remedy.
The Park Tools book (probably that bit also on their website) is very good on CORRECT chain length.
I'd get the chain to THAT length, not mess with it, then set to work on the other variables.
And as above from T4tomo, Park is also excellent on adjusting gears.

 

[Milkfloat]

Do you have the correct sized derailleur for a 32 cassette, plus check your cable routing carefully.

 

[Twilkes]

Do you have the correct sized derailleur for a 32 cassette, plus check your cable routing carefully.

I think the 32t was outside the recommended limit of the derailleur, but there are plenty of examples on YouTube of people running it successfully, and it worked fine before, hence me thinking I should size the chain for the 28t sprocket, as the previous chain was.

Weill check everything else first before taking out a link though.

 

[Brandane]

Forgive me if I'm teaching my granny to suck eggs here, but...
When you cut the new cable outer, is there a chance you might have compressed the end of it thereby causing inner cable drag? I've had that problem before, cured by putting a suitable size of nail into it to open it up prior to fitting.

 

[Blue Hills]

I think the 32t was outside the recommended limit of the derailleur, but there are plenty of examples on YouTube of people running it successfully, and it worked fine before, hence me thinking I should size the chain for the 28t sprocket, as the previous chain was.

Weill check everything else first before taking out a link though.

agh!
See above.
You size the chain for the chainring/cassette set-up that's actually on the bike, not whatever it may have been before, wot your aunty's bike has, or a number rolled from the dice.
See Park above - chain sizing is actually pretty simple following their system.
If you run a chain too short for what's on the bike (and last time I looked 28 is less than 32) you risk doing some serious damage.
And having to start a new thread.

On the other point - yes - shimano's mechs often have more capacity than shimano say, though I stress I don't know if yours will take a 32. But that's an entirely different point to chain length.

 

[fossyant]

I'd double check the cable is running smoothly as everything was shifting OK on the old parts.

 

[Twilkes]

I'd opened up the ends of the cable with a screwdriver before threading the inner, and it all seemed to be moving freely when I tested it without the wheel fitted, will check again though.

 

[Twilkes]

Okay the cables are sound but I found some side to side play in the derailleur itself - the part that's bolted to the frame seems solid, but the further away I get from that the bigger the movement. It's probably enough to affect the shifting at both ends, given the tolerances.

What can I check on the derailleur, tighten screws/springs etc?

If it's a new derailleur, is there much benefit in upgrading from Tiagra to one of the higher range Shimano derailleurs?

 

[Slioch]

Another possibility could be your "B" screw adjustment on the derailleur. I had a similar problem with shifting and closed the gap as much as possible without it quite touching, and that seemed to fix the problem.

 

[Big John]

I've fettled a lot of rear mechs from Tourney (and below) to Ultegra (never Dura Ace, sadly) and I've always found all of them are pretty accurate in their shifting. I don't think changing upwards will make any difference.

 

[Ajax Bay]

is there much benefit in upgrading from Tiagra to one of the higher range Shimano derailleurs?

Current Tiagra is 10sp. Edit (after @Twilkes post below!) deleted
Anyway, that's still a "no".

 

[Twilkes]

Current Tiagra is 10sp. You'd have to change lots to go to 105 (11sp).
Anyway, that's a "no".

Current Tiagra can use an 11 speed derailleur as the pull ratios are the same, but when it worked the Tiagra derailleur was fine so I'll stick to that.