Rear derailer repair or replace?

Gubbins

Esteemed Pedelecer
Last year i crashed on black ice and bent the rear changer so LBS straightened it out and indexed the gears but it has never been just right.
By using the lever fine adjuster I can have a smooth change up the gears or down the gears but not both so I choose up the gears (low to high) because when changing down (high to low) I can give the lever a little nudge to make the change stick whereas going up I can't.
It manifests as a random late shift after the change or a double shift if I change again. (If that makes sense)
Looking at it it looks ok but I don't know what I should be looking for and if I engage the clutch it gets worse so before I spend more money having someone try to sort it would it be better to just buy a new one?
Using it as it is isn't too much of a hassle but I will be selling it at some point so it needs to be right.
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,127
6,314
once you bend the mech hanger it should be replaced as it will never be the same if you bend it back in to shape.

it dont take much to screw up all the gears even if it has a tiny bend in it.
 
  • Agree
Reactions: Skippy

soundwave

Esteemed Pedelecer
May 23, 2015
16,127
6,314
DSC_0104.JPG
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,127
6,314
the top bit is the mech hanger and is held on with that screw top right so i bet thats gone back to being bent so id replace it.

mine never looked bent till i tried to fit my 12spd derailleur to mine and no chance it would work with it bent so had to replace mine.

if you still cant index the gears then id change the derailleur but it looks fine from the pic.
 

Gubbins

Esteemed Pedelecer
the top bit is the mech hanger and is held on with that screw top right so i bet thats gone back to being bent so id replace it.

mine never looked bent till i tried to fit my 12spd derailleur to mine and no chance it would work with it bent so had to replace mine.

if you still cant index the gears then id change the derailleur but it looks fine from the pic.
I presume the hanger is available as a spare..
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,127
6,314
I presume the hanger is available as a spare..
yeah you just need to find the right one for ur frame imo the lbs cant sort one for you.

you can bend them back but once there bent it should be replaced as there meant to bend/brake so not to damage the derailleur.
 

Ballynoes

Esteemed Pedelecer
Jul 13, 2017
257
146
Perthshire Scotland
The Hanger is there exactly for your reason... it's a sacrificial part and should bend/break before your derailleur or frame does, as those are really expensive.

Most are available as a replacement part, and indeed I carry one in my rucksack as a spare.

Mine comes off with two allen screws and is easy to change.

Some can be expensive for what they are but much cheaper than replacing a derailleur or the frame.
 

awol

Esteemed Pedelecer
Sep 4, 2013
1,216
374
I have the Park Tool version and wouldn't be without it. The X-tools version represents brilliant value for money. :)
I got the Park tool one too when it was on sale half price. It paid for itself straight away, I adjusted 3 bikes and got smoother gear changes on all. But yes the X-tools version does look very similar and good value.
 
  • Like
Reactions: EddiePJ

Gubbins

Esteemed Pedelecer
I got the Park tool one too when it was on sale half price. It paid for itself straight away, I adjusted 3 bikes and got smoother gear changes on all. But yes the X-tools version does look very similar and good value.
So what does the tool do? I think it's bent, not in need of adjustment. Or am I missing something
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,127
6,314
i cant use that on my bike as the rear hanger is part of the frame and the axle also goes through it.

So what does the tool do? I think it's bent, not in need of adjustment. Or am I missing something

the tool is for checking the mech hanger tho you can use it to bend one back in to shape but best off buying a new one if it has had a hard whack.

mine was bent and twisted so could not get the new derailleur on as the thread was fooked.
 

awol

Esteemed Pedelecer
Sep 4, 2013
1,216
374
Before buying a tool, first I would check the gear inner cable is running free and smooth through the outer. - Put the bike on a stand so you can turn the crank and change to the highest gear (smallest cog), then change gear a few times by pulling the gear cable downward under the chainstay whilst turning the crank and just feel if it seems smooth and also returns smooth with no sticking.
Then I would press against the deraileur inward and downward so that cable inner goes slack and the outer can be unhooked from the chainstay.
Now turn the crank and this should run smooth in the highest gear with no cable tension at all.
 

Gubbins

Esteemed Pedelecer
Before buying a tool, first I would check the gear inner cable is running free and smooth through the outer. - Put the bike on a stand so you can turn the crank and change to the highest gear (smallest cog), then change gear a few times by pulling the gear cable downward under the chainstay whilst turning the crank and just feel if it seems smooth and also returns smooth with no sticking.
Then I would press against the deraileur inward and downward so that cable inner goes slack and the outer can be unhooked from the chainstay.
Now turn the crank and this should run smooth in the highest gear with no cable tension at all.
That was replaced after the crash and is fine. It's just a nickety pickety fine adjustment that goes one way or the other. LBS says they will have a look at it and worst case is a new changer at £90 + fitting. Will go down the replacing the hanger bracket thing first and see what happens. I can get a changer on line cheaper but means me fitting and setting up myself..
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,127
6,314
you found the right mech hanger yet ? scott enit ;)
 

Related Articles

Advertisers