Slow-witted derailleur

[nirakaro]

3x9, Sora shifter, Deore mech: the shift was getting kinda rough, so I’ve cleaned n lubed the chain, cleaned n lubed the mech, new jockey wheels. Now it all shifts sweet as a nut – when it gets round to it. On the upshifts, it tends to wait two, five, ten seconds before it does the job.
I’m guessing this is down to stickiness inside the cable outers? The cables aren’t new, but they’re not very old either. Should I lubricate them? (I’ve heard that some cable outers will swell up and get worse with oil.) What with? Chain lube? 3-in-1? I’ve got some powdered graphite that’s specifically for non-sticky lubrication of locks – would that be a good idea? Or what?

[jb]

Stickiness would cause the shifter to be stiff. It would not delay a change, more likely is a bad joint where the outer cable meets the stop. Or the chains so worn that it flexes rather than be pushed over by the pulley.

[geomannie]

Could very well be the cables. From what you describe my next step at the very least would be to pull the cables from the outers and have a look. Perhaps they are corroded or worn? If they look ok I would lube and reinstall them. If corroded or worn I would replace the cables & possibly the outers.

[531colin]

Slow UPSHIFT is classic for sticky cable.
The shifter can’t be “stiff” because all you are doing is releasing the upshift pawl; the mech. spring pulls the cable through….slowly when it needs lube.
I put a drop of engine oil between finger and thumb and draw the cable through; first get lots of cable slack by taking the cable outer out of the slotted cable stops.

[Audax67]

I put a squirt of silicone down inside the outer when I fit it. If I remember.

[Brucey]

.... Should I lubricate them? ..... What with? .....

IMV they should be lubricated, but as you say not all housing types like it. Swelling is usually accompanied by softening, and liner softening is more of a worry with most cables. It is not difficult to make up sample bottles, each one containing a short length of liner and a potential lubricant. What can be difficult is interpreting the results; few polymers are completely inert when given long-term exposure to lubricants, solvents etc. Lubricants which are based on mineral oil typically contain a mixture of isomers, any one of which could be causing a problem in the long term. Lubricants which use synthetic oils typically contain just one isomer, so if there is a adverse reaction, it should be relatively swift and obvious.

This is why I use a grease containing a synthetic oil on my cables. Silicone oils also do not have a reaction with most plastics, but they are not as good as lubricants.

[Cyclothesist]

I usually squish GT85 down the lining of the outers as part of fitting new cables. I've been doing that for years without apparent degradation of the lining (Shimano outers).
In the past I've tried wet chain lube but I found that it's too heavy for the job and more liable to collect dirt. Dry lube is worse, it's too sticky once it's dried even with PTFE containing dry lube.

[Tandem Tom]

As a touring cyclist I had this "hesitation " problem for years. On our recent tour,we just got back, cycling across the US. I had to replace my chian. I had always used Sram on my 9 speed drive train. But the shop only had Shimano. Within 1 mile absolutely no "hesitation "!
I work at in a bike shop and we use both but I had always used Sram on our personal bikes.

[nirakaro]

Right, that’s helpful. I’ve lubed the outers – graphite and a bit of 3-in-1, and it all feels silky-smooth, but the shifting is only slightly better. The problem seems worse at the top and bottom of the range. I’ve got a new Shimano chain, so I’ll try that next. If that doesn’t help, I’ll borrow the mech off my other bike, see what that does. Thanks.

[Cyclothesist]

Just a thought, have you checked your derailleur hanger alignment? If it's bent it can cause no end of shifting mischief.

[Brucey]

Just a thought, have you checked your derailleur hanger alignment? If it's bent it can cause no end of shifting mischief.

originally shimano specified that the hanger should be set 0-+0.5 deg 'toe-out' and 0-0.5 deg negative camber. This soon goes out if the bike just falls over.

[nirakaro]

There isn't a separate hanger, the mech fits direct to the frame. I doubt if I could spot half a degree misalignment.

[nirakaro]

Well I’m bemused. I changed the chain – which was a bit elongated (I daren’t say stretched!), though not excessively, but no improvement. Swapped the mech, Deore to Deore XT, and it’s absolutely fine. Close look at the old mech, I can’t see anything amiss or out of alignment. Happy ending, but I’d love to know why.

[853]

Well I’m bemused. I changed the chain – which was a bit elongated (I daren’t say stretched!), though not excessively, but no improvement. Swapped the mech, Deore to Deore XT, and it’s absolutely fine. Close look at the old mech, I can’t see anything amiss or out of alignment. Happy ending, but I’d love to know why.

My guess - and it is very much a guess - is that the spring in the Deore mech is no longer up to the job.

[Cyclothesist]

It could also be the pivots are stiff. Moving the derailleur by hand without a cable installed will give you an idea of how strong the return spring is and whether it's holding up on stiff pivots.