Front derailleur

[bunkers6303]

I can only access the top 9 gears of 27. I took to Halfords and the mechanic said that the front derailleur has seized and needs replacing. They could not replace because there is a shortage of this part and unlikely to be available until November at the earliest. Mechanic advised to search online for replacement front derailleur but I do not know the exact part and although there are a lot online I am not sure it will fit my bike. The bike is a 3 year old Carrera Subway and the derailleur is Altus. I can manage on the available gears but does anyone have any advice about replacing or repair?

 

[brucers]

Is the derailleur clogged with mud or rusty? Did it seize gradually or all at once? When you try to change the gear does the shifter feel like it is straining the cable or does it move without strain?

 

[Ajax Bay]

Besides advice from Bruce above.
This is an unusual FD fail unless the bike's been left outside unoiled. More likely this is shifter related but let's go on what your LBS said.
Remove the cable (under control). Does the cage just stick above the large ring?
Drown the FD with WD40 and give it a really good clean.
Can you not work the cage side-to-side by hand (shifter to 1 if cable attached)? Chain oil it and leave overnight: try again.
Let us know how you get on with that.
Replacement one-for-one (if it comes to that) is an Altus triple but will need to be the right band size for the seat tube on your Carrera (band-on not braze-on assumed). Used ones are widely available, but mostly any triple FD make/model will do (don't go there yet).

 

[Mike_P]

Are not Halfords and LBS mutually exclusive?
Agree that it most likely has simply got clogged up with muck especially if it's been ridden on filthy roads etc without full length mudguards.

 

[Blue Hills]

If you end up going for a new one OP I think you need to say what diamater the mounting tube is (tho adaptors are available) and what your chainrings and rear cassette are.

 

[Ming the Merciless]

As above, soak mech in WD40 or other penetrating oil. Give it a good scrub with a wire brush if rusted / dirty. Leave it a while. Then try and move cage by hand.

 

[bunkers6303]

Thanks everyone. I have only just realised to check for replies. You have reminded me the the Halfords mechanic did say I could try whacking it with a hammer but I ignored that advice! I will try soaking in WD40 and leaving it. It was working fine until a couple of weeks ago. I have not been out in bad weather much in the last two years and the bike is kept in the garage. I now realise that I am guilty of not keeping the derailleur clean and greased though. I will have a go at freeing it and let you know how I get on. Thanks again.

try your dugg

 

[bunkers6303]

I tried soaking in wd40 and oil, cleaning and leaving wd40 overnight but it has made no difference. The cage cannot be moved by hand. It is rock solid.

 

[Ajax Bay]

https://www.merlincycles.com/shimano-altus-m370-rear-derailleur-9-speed-237164.html for £30.
Doesn't have to be Altus, but may need to be SGS (length of cage) depending on your chainring range and cassette sprocket range.
See also my post #3 above for other considerations.

 

[bunkers6303]

Thanks Ajax Bay but that is a rear derailleur and mine is the front derailleur.

 

[Ajax Bay]

Sorry - brain fart. As I said in post #3, "mostly any triple FD make/model will do" with "the right band size for the seat tube" with bottom pull.
Maybe this one? https://www.teamcycles.com/componen...-fd-m371-altus-9-speed-front-derailleur__4792

 

[si_c]

If the derailleur is stuck in the top gear then it could be a few things, least likely is the derailleur.

Disconnect the cable and then try moving the arm, the cable holds it in place so you won't be able to get it to move until you do so. If the derailleur is fine then it will snap into place over the smaller ring.

If it does that then it is probably the cable or the shifter which is at fault. Try moving the shifter with the cable disconnected and see if that moves or not, if not the most likely cause is the cable being stuck inside, so try removing that and see if the shifter works. If it does then just replace the cable.

 

[GuyBoden]

Measure your Seat tube dia with an adjustable spanner.
https://www.homehacks.com/adjustable-wrench-caliper/

 

[Ajax Bay]

Disconnect the cable and then try moving the arm

Si - have you read the rest of the thread?

 

[si_c]

Si - have you read the rest of the thread?

Yep, but I'm working on the assumption that the trained monkey in halfords did little to no diagnosis of the fault besides wiggling the shifter and declaring it in need of replacement, so starting again at first principles.

Edit to add: I know the OP said that they tried moving it by hand, but they didn't say whether they had disconnected the cable, as it's bottom pull it wouldn't help with diagnosis if they didn't.