Rear derailleur sticking

Rear derailleur sticking

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Discussion

gazza285

9,780 posts

207 months

Wednesday 16th June 2021
quotequote all
sclayto2 said:
And another tip, when ever you put the bike away always make sure to take the tension out fo the cables.
Why?

Maximus_Meridius101

1,222 posts

36 months

Wednesday 16th June 2021
quotequote all
gazza285 said:
Why?
Stress corrosion. If you store the bike with the cables under tension, eventually they could fail spontaneously. Releasing the tension stops it.

Maximus_Meridius101

1,222 posts

36 months

Wednesday 16th June 2021
quotequote all
Some Gump said:
This, but also an additional thing once you start doing long rides.

if you can't fix the bike at home, what are you going to do 40+ miles from home, poss 30 miles from a train station if it goes tits up?
Have a word with myself / whoever planned the route. I deliberately plan all my longer routes to never be more than a maximum of a 6 mile emergency hike, from somewhere I can be evacuated with a badly broken bike. Be that a train, or ‘phone a friend’. I always include emergency extraction points, be they an easily located pub, an easily located / well known landmark, or a station, in my routes. The what3words app is a godsend too, but relies on a working phone.

Some Gump said:
The ability to on the fly jury rig fixes for e.g a failed derailleur (with limit screws and a cable tie), to fix a snapped chain, etc etc are really useful if you're going further into the boonies.
OK some people will say "I'll just call the missus" but I'd much rather be self sufficient =)
That is useful stuff to acquaint yourself with, in any case.



Edited by Maximus_Meridius101 on Wednesday 16th June 12:57

okgo

37,857 posts

197 months

Wednesday 16th June 2021
quotequote all
gazza285 said:
Why?
Nobody since the big bang has ever done this though.

IJWS15

Original Poster:

1,830 posts

84 months

Wednesday 16th June 2021
quotequote all
louiebaby said:
Hanger alignment is always the first thing I do now when something seems to have changed. It's easy to knock the derailleur and move it, especially the kids on their bikes. (I have educated them not to lay their bikes down on that side, but they're kids.)

The tool can be a bit pricy, but I have used it so many times over the years, it's been worth it:

https://www.wiggle.co.uk/lifeline-pro-gear-hanger-...

Other options are out there though.
When mine got bent it was beyond repair and was replaced.

louiebaby

10,651 posts

190 months

Wednesday 16th June 2021
quotequote all
IJWS15 said:
When mine got bent it was beyond repair and was replaced.
Every new bike I've bought has been a little bit out too. Just because it's a new hanger, it doesn't mean it's straight WRT the wheel or the frame.

Even on a Cervelo S3, with electronic shifting. (I was a bit disappointed that the mechanic that built it up hadn't trued the hanger, to be honest.)

flight147z

960 posts

128 months

Wednesday 16th June 2021
quotequote all
If changing the cable don't underestimate the difference that changing the outer at the same time as the inner makes

For ages I just changed the inner, I got to the point where I was having the same issues as described in this thread when changing up to a larger cog at the rear, either the change wouldn't happen immediately or wouldn't change unless I changed "up" two gears then "down" one. Changing from a larger to smaller cog on the rear always worked fine and adjusting the indexing made no difference

In the end I decided that there must be friction in the cable housing somewhere so I changed the inner and outer cable. Resolved the problem immediately and noticeably lighter shift action after the change too

For sorting through general rear derailleur issues I'd suggest the following:

Before doing anything a full degrease and clean until no dirt comes off the cassette or chain when you touch either with your fingers. If there is still dirt keep cleaning. Dry once done. I'd then suggest dry lube, wait ~4 hours before riding. A clean drivetrain can solve a tonne of problems

Chain won't shift into cogs at the extreme ends of the cassette
Check that the derailleur is aligned under the cogs that you can't shift into when the shifter is in the right position for those gears, if it isn't then the limit screws need adjusting. The only exception to this is if the chain won't switch into the biggest cog, if it won't do that then try pushing the derailleur towards the wheel to see if that makes the chain shift, if it does then the limit screws are fine, the cable just needs more tension. Be careful with adjusting these as if you get it wrong you can throw the derailleur into the spokes (as someone has noted above). You want the limits to be set so that the derailleur can only just reach the extreme gears.

Rough shifting/noise but all gears are usable
Indexing probably out or the B-screw is in the wrong place. I'd set the B screw so that the upper jockey wheel is as close to the cassette as you can get it without it touching in any gears (aim for a small gap - it's usually closest when you are using the largest cog). If that doesn't solve the problem then try adjusting the cable tension by small amounts until the shifting is cleaner (there is more detail on how to do this efficiently in the Shimano manuals). This is basic indexing and is a really easy skill to learn

If the above don't sort the problem then I'd try a new cable (inner + outer) then as a last resort a new derailleur (unless you have the tool required to check derailleur alignment before assuming it needs to be replaced)

gazza285

9,780 posts

207 months

Wednesday 16th June 2021
quotequote all
Maximus_Meridius101 said:
gazza285 said:
Why?
Stress corrosion. If you store the bike with the cables under tension, eventually they could fail spontaneously. Releasing the tension stops it.
It’s a push iron, not a suspension bridge, how much tension do you think a gear cable is under?

Pickled Piper

6,334 posts

234 months

Wednesday 16th June 2021
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9 times out of 10 the answer is change the cable, clean and lube the derailleur and re index the gears. Everything you need to know is on YouTube. The Park Tools guides are great.


uncinqsix

3,239 posts

209 months

Thursday 17th June 2021
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budgie smuggler said:
gazza285 said:
How will tightening the cable help with slow changing into a higher gear? That would make it worse.

Anyway, my money is on the cable.
You're right, it's because he said "changing up" and for some reason I have it in my head that means going onto the larger gears even though that makes no sense.
Unless he has a rapid rise rear mech spin

I have one on my commuter and it's been doing the same thing lately, so your suggestion is quite valid in my case.

gazza285

9,780 posts

207 months

Thursday 17th June 2021
quotequote all
uncinqsix said:
Unless he has a rapid rise rear mech spin

I have one on my commuter and it's been doing the same thing lately, so your suggestion is quite valid in my case.
Wierdo.

uncinqsix

3,239 posts

209 months

Thursday 17th June 2021
quotequote all
gazza285 said:
Wierdo.
I didn't read the description properly when I bought the derailleur paperbag


However, it's grown on me and I actually really like it now, which is probably worth another paperbag

take-good-care-of-the-forest-dewey

5,071 posts

54 months

Thursday 17th June 2021
quotequote all
gazza285 said:
Maximus_Meridius101 said:
gazza285 said:
Why?
Stress corrosion. If you store the bike with the cables under tension, eventually they could fail spontaneously. Releasing the tension stops it.
It’s a push iron, not a suspension bridge, how much tension do you think a gear cable is under?
There really is some alarmist nonsense posted in the cycling forum.

In next week's alarmist post... don't forget to blather your carbon frame in factor 50 to prevent UV degradation of the resin.

Tabs

941 posts

271 months

Thursday 17th June 2021
quotequote all
As mentioned, most probably a new inner cable at the very least, outer as well preferably.
Favourite places to fray are at the bottom bracket guide and at the nipple end inside the lever.
If you do replace the inner only, be aware that some outer cables have built in shrouds where the cable comes through. These seem to be heat shrunk on and a centimeter deep. Trying to push a cable through can take ages. I have resorted to opening the hole up with a small screwdriver in an effort to get it to go through.
Removing the adjustable barrel from the derailier, cleaning up and lubricating will also allow easier indexing adjustments. Watch out for flying spring!

IJWS15

Original Poster:

1,830 posts

84 months

Tuesday 22nd June 2021
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Fathers day brought some tools and a cable set, investigation started and I found the bearing loose and tightening that a little allows the brakes to change properly.

However on reading up about setting bearings you set them at the free end and it is the drive end that is loose . . . Took the cone out and it has some pitting, replaced it with some grease for now. Spoke to LBS (being tight I don't want to sign a blank cheque for them) and will strip it all down and clean to check that the hub is OK and assess from there.

In the early days the bike obviously wasn't set up correctly and on a couple of occasions the chain dropped over the large gear, having had the cassette off I decided it would be wise to change a few spokes.

Just need some time to strip the hub down and check it over and take a spoke out before I go back for the right bits. Looks like I will be riding the old bike for a few days.

IJWS15

Original Poster:

1,830 posts

84 months

Tuesday 6th July 2021
quotequote all
Left the wheel with a shop in Stafford 2 weeks ago to change 8 spokes and true the wheel, they didn't have cones that would fit and Giant say they are no longer available for that hub . . .

Took the axle with me to try to find cones. Realised the following day that they would probably need the axle and dropped them an e-mail asking if they did. Called them last Thursday later to be told that they had fitted the spokes but needed the axle (hadn't seen the e-mail, hadn't called me) but their wheel builder wouldn't be in until Tuesday (today) so I collected the wheel. Won't be going back there if I can avoid them, very poor communication.

Dropped in to Sanders in Brownhills who, when I called, said they may be able to help but needed to see the wheel. They had an axle so they trued the wheel and installed new axle and bearings. They called that afternoon to say it was done and ready to collect. They advised that it has a slight mark on one of the cups but should do a year or so before I need a hub.

Did 20k yesterday lunchtime and gear change is fine, haven't changed the cable yet.