rousseau

I've loosened the limit screw and the cable tension on the rear derailleur as much as they'll go, and everything shifts peachy, up and down, except for one particular upshift from the fifth to the sixth cogs when I'm in the big ring.

There's a delay of a couple of seconds. And sometimes it just doesn't go. What to do?

I've got a hunch: Should I remove the cable and grease it up real good? I've had the cables and housings on the bike for about a year now. Is my problem a tell-tale sign of cable-to-housing friction?

Elduderino2412

i would undo cable at RD and tighten barrel adjuster all the way, so you can tune your RD. Wouldn't hurt to replace and wax your cables when doing that anyway if you have some lying around.

EDIT: i just realized you said limit screw and not barrel adjuster. Limit screws are only for highest and lowest limits, so the chain stays on the cassette.

JerrySTL

Unless you have a 6-speed, loosening the limit screw won't do nothing.

Could be time to clean and lube the cable. Shift the rear all the way up to the big cog. Without turning the rear wheel, shift towards the smaller cogs. Now the RD cable should be very slack. You can clean and lube the cable and guide under the bottom bracket. You should be able to remove the cable housing off the chain stay and slide it out of the way to clean and lube that part of the cable. After that make sure that the cable and housing are all where they should be and shift back up to the large cog. Then double check that the cable is still properly in the guide under the BB. I recommend a teflon spray and not grease.

rousseau

Awesome advice, thanks!

rousseau

Oh, a question: I'm not familiar with teflon spray. Got a brand name you can give me?

rpenmanparker 

OP, I suspect you mean downshift, not upshift. I don't know why, jt just seems that is what you are talking about. I apologize if I am wrong. You are downshifting if you mean the 6th cog from the dropout. Larger cogs are downshifting. It could be just the need for tightening the cable with a turn or two of the barrel adjuster. Or other things already suggested.

rousseau

On a ten-speed cassette the 1st cog is against the spokes and the 10th cog is against the dropout. When you say you're upshifting from the 5th to the 6th cogs it's obvious that you're talking about going outward and away from the middle of the wheel, i.e. upshifting. And I did clearly use the term "upshifting."

Besides, this kind of specific problem between the middle cogs never really happens with downshifting. You never get a situation where the upshifting is completely fine but the downshifting is off on one shift.

rpenmanparker 

I was mistaken about your meaning and apologize. What threw me is your counting from the spokes. See, the neutral position for the derailleur is all the to the right (facing forward). That is where the derailleur sits when there is no tension on the cable. It is also the neutral or zeroed position of the shifter. So I always count by increasing tension on the cable and moving the derailleur to the left. Semantics I suppose.

popeye

You have a kink in the shift cable. Consider cables consumables.

jdon

Maybe just wear or dirt as well. Waste of time cleaning and lubing. It is time for a cable change.

popeye

Also check for a fraying cable end in the brifter.

rousseau

Yeah, you're right, I should just get a new cable.

Erwin8r

That always seems to solve unreasonable shifting issues for me (after everything is adjusted and tensioned properly and still mis-behaving)...

Bob Dopolina 

How old is the cassette?

If these are cogs you use a lot more than others it could also be a sign of wear. The cogs are chain are most worn to each other and therefor the chain is hesitant to drop out of those cogs.

Most likely is is a kink or fray in the inner cable but if that doesn't resolve the issue measure your chain and inspect you cogs for excessive wear.

rousseau

Well, that didn't work. I put a new cable on, even smeared the entire length of it in grease, but same thing: no smooth upshifting from the 5th to 6th cog.

Thanks for the suggestion, Bob. My chain is still pretty much at 12 inches, it's just a hair over, so according to that test the chain isn't worn much. The cassette? It's a year and a half old and probably has about 10,000 km on it. Maybe I should get a new chain and cassette?

sfrider 

For upshifting you release tension and the RD should just pop out since it's spring loaded. If it doesn't, something is sticking. You ruled out the most obvious (cable). The next step is to carefully clean out and lube the RD to make sure it moves smoothly. The chain and cassette don't impact upshifting.

If the derailleur moves nicely but it still doesn't shift, then check that the cage and pulleys aren't loose or damaged.

rousseau

I'm going to try that next. But if the derailleur should just "pop out" due to the spring, isn't it odd that it only seems to delay in shifting from the 5th to the 6th cog and not really the others? Well, from the 6th to 7th is a bit slow, too, but then after that it seems to be mostly fine.

But I'll clean and lube the derailleur first to see if that does the trick.

Bob Dopolina 

Incorrect.

Cogs with shark fins can slow the release of the chain and cause shifts that are slow and clatter regardless of direction.

Bob Dopolina 

No.

There could be something very specific wedged in somewhere or the plating could be worn away in a pattern (exposed metal from wear - or worse - gouges from a crash) that means the parts won't work as well together. A good cleaning and lube can often be the solution. If even only for the short term.

If you service the der and it seems fine but the problem returns after a short while then you have a bigger problem; Your der is toast.

sfrider 

Yeah, but it seems awfully unlikely that a worn or damaged sprocket would shift cleanly in one direction yet cause delays in the other. But I suppose it's theoretically possible...

I do think the RD is more likely though, and in any case a thorough cleaning and inspection for wear or damage can't hurt.

Oh, another thing: if it's a newly installed cassette, make sure the spacers are in the right places.

Bob Dopolina 

Agreed.

It's free and it's always my first step when troubleshooting.

CALE262

Bent hanger...?

Bob Dopolina 

You can get a der to sort of work on a bend hanger but the troubles occur at the limits of the cassette, not in the middle.

dalava

Not necessarily. I had a bent der hanger not long ago and impacted shifting in the middle 3 cogs. S it doesn't hurt to check the der hanger.

Bob Dopolina 

I agree that alignment should be checked. It is another quick and free troubleshooting step.

1. Remove, clean replace
2. Check that everything is tight enough but not too tight.
3. Check alignment and range of motion.

Then isolate one item at a time until the problem item presents itself. It is quite possible that there is more than one problem involved

Specifically items like;

1. Cracked spacer between cogs or incorrect spacer.
2. Frayed or kinked inner cable.
3. Cracked ferrel or the wires in the gear cable housing are pulling through the end of the ferrule at the point where the cable housing enters the shift lever.
4. Lockring not torqued to spec
5. Housing loop from frame the RR der is too short.
6. Component compatibility issues
7. Chain line issue.

OP what group are you running? There could also be some idiosyncratic behavior presenting itself.