Derailleur not dropping onto outer cogs - adjustment or maintenance?

Jim Newmark

I have spent more time than I care to admit trying to fix this - including wasting time and money on a new cable. It was working perfectly before, but now it won't drop onto the highest gear without my pushing the derailleur outwards with my finger the last half inch or so when on the stand. The cable goes slack but it as if the spring simply isn't strong enough to return it to the correct final position. It is probably maintenance, but it hasn't been helped by lubricating everything in sight. What is the next stage? I suppose that I could take the whole derailleur off, dismantle it, clean it up, and then put it back but I haven't done that before and it seems a bit drastic. Is there an easy fix to this? Have I missed something?

bbrap

If the cable is slack and it still does not go by itself you will need to give it a thorough clean and re-lube. Probably grit or something causing it. Best bet is to take it off, flush it out and make sure it moves freely. Then re-lube and put back on the bike. Do the jockey wheels while you are at it.

Jim Newmark

bbrap wrote:

If the cable is slack and it still does not go by itself you will need to give it a thorough clean and re-lube. Probably grit or something causing it. Best bet is to take it off, flush it out and make sure it moves freely. Then re-lube and put back on the bike. Do the jockey wheels while you are at it.

Thanks, but it is not the cable - that is what I first thought before I looked more carefully. With the shift in the top gear position the cable is slack where it enters the derailleur mechanism ie it would allow further movement of the derailleur if the darn thing wasn't so reluctant to move without my pushing it manually the last bit. It must be the derailleur itself - I was thinking of messing with the B adjust screw to see what happens, but that is not really its purpose.

bbrap

Don't move the B screw. It will be the pivots for the paralellagram part of the derailleur which are sticky. Take the cable off the mech, flush it with a degreaser, wiggle it about to free it up then re-lube.

Jim Newmark

bbrap wrote:

Don't move the B screw. It will be the pivots for the paralellagram part of the derailleur which are sticky. Take the cable off the mech, flush it with a degreaser, wiggle it about to free it up then re-lube.

Ah, I see what you mean, sorry - not the cable, sort out the derailleur. Yes, makes sense, but I have already relubed and wiggled without effect. But I agree that I haven't used degreaser first so I will give it another go. And leave the B screw alone!

bbrap

Sorry for the confusion. Its definitely your mech not your cable that is the problem.

Alex99

Jim Newmark wrote:

bbrap wrote:

Don't move the B screw. It will be the pivots for the paralellagram part of the derailleur which are sticky. Take the cable off the mech, flush it with a degreaser, wiggle it about to free it up then re-lube.

Ah, I see what you mean, sorry - not the cable, sort out the derailleur. Yes, makes sense, but I have already relubed and wiggled without effect. But I agree that I haven't used degreaser first so I will give it another go. And leave the B screw alone!

Sounds like it must be the derailleur. So, if I understand, even if you disconnect the cable, it don't shift down the cassette? Is the return spring broken?

Is the nuclear option to submerge the derailleur in e.g. white spirit and work the mechanism (with gloves on, in well vented area) and see if things free up?

Jim Newmark

Alex99 wrote:

Jim Newmark wrote:

bbrap wrote:

Don't move the B screw. It will be the pivots for the paralellagram part of the derailleur which are sticky. Take the cable off the mech, flush it with a degreaser, wiggle it about to free it up then re-lube.

Ah, I see what you mean, sorry - not the cable, sort out the derailleur. Yes, makes sense, but I have already relubed and wiggled without effect. But I agree that I haven't used degreaser first so I will give it another go. And leave the B screw alone!

Sounds like it must be the derailleur. So, if I understand, even if you disconnect the cable, it don't shift down the cassette? Is the return spring broken?

Is the nuclear option to submerge the derailleur in e.g. white spirit and work the mechanism (with gloves on, in well vented area) and see if things free up?

Thanks. No, the spring isn't broken, just "not strong enough!". All this makes sense and it gives me something to work on to relieve my frustration. Also reassurance that despite relubing and fiddling already I can go that bit further!

svetty

Are you sure the limit screw hasn't moved - or that the hanger isn't bent?

Jim Newmark

Svetty wrote:

Are you sure the limit screw hasn't moved - or that the hanger isn't bent?

No, because just a little bit of pressure with my finger does the job when on the stand, but which is a bit impractical when needing the higher gears on a downhill. I am convincing myself that all it is will be just a bit more proper lubrication when I am motivated enough to go to the garage.

The Rookie

I got this on my commuting bike, a wee bit of GT85 on the 8 pivots for the parallelogram, work in back and forth lots of times, wipe with kitchen roll, repeat until it's moving freely, leave for the GT to evaporate overnight and then put a drop of oil (3 in 1 works well) on the 8 pivot points.

fat daddy

I had one do this a few years back, I sprayed it with every cleaner known to man and it didn't cure it .... the LBS told me to remove the derailleur, soak over night in white spirit.

then rinse, lube reassemble and lube

worked fine after that ..... I guess it needed a better clean