Author Topic: I stuffed up my rear derailleur hanger :-( (Read 6185 times)

francisbarton · « **on:** 10 April, 2008, 04:42:08 pm »

I got an old and rubbish bike off Freecycle recently, cleaned it up, did some work to the wheels, replaced the rear brake cable and adjusted the brakes, adjusted the saddle, refurbished the pannier rack, and cleaned and oiled the chain. Since then I have been using it for little shopping trips and have also fitted a child seat to the back and have been really enjoying going for little rides with my daughter on the back.

I was noticing quite a lot of noise from the chain, so I checked the derailleurs, and found that the rear was screwed into the dropout slightly wonky, so that the cage below is sticking out at an angle away from the frame.

I am pretty sure I did this when I was cleaning the bike - I had unscrewed the whole derailleur in order to give it a good brushing (I now realise this was almost certainly unnecessary) and I must have stuffed up the thread when refitting it.

Today's top tip: do not do this.

I bought a 10mm thread tap off ebay and have just been trying to retap the hole, which was fun. I thought I'd done it OK, but the derailleur screw just won't tighten - I think the thread is gone for good. I am wondering if it worth trying to use some horrendous glue to try to bind the screw in there permanently?

Anyway, I stuffed up and I'm not really expecting any solutions (though I would welcome them). I'm posting this here as a warning. Sympathy would be nice, but derision more appropriate. At least the bike didn't really cost anything.

I expect someone will be along to suggest turning it into a fixie

border-rider · « **Reply #1 on:** 10 April, 2008, 04:46:17 pm »

Turn it into a...oh

If it's a decent frame, have it rethreaded, though this may involve paint damage cos it will involve brazing

If it's a hack you might contemplate using metal-loaded epoxy to stick it in - or if the buggeration isn't so bad, try plumbers' tape. neither are likely to work though, to be honest

The other option is an old-fashioned bolt-on mech hanger like wot bikes often had before dropouts incorporating gear hangers were common. These have a little bolty thing that secures them into the dropout behind he axle. I have a spare one in the bits box, but I'd have to rummage for the bolty bit cos it was missing when I saw it last week.

edit:

One of these

http://www.swinnertoncycles.co.uk/Index-Gear-Hanger-With-Nut-Bolt-Fisaw06gp551.aspx

MSeries · « **Reply #2 on:** 10 April, 2008, 04:47:52 pm »

Rear mech threads are 10mm fine not M10. Glue it in, what the heck.

francisbarton · « **Reply #3 on:** 10 April, 2008, 04:51:01 pm »

Thanks MV. It's most definitely a hack. I think I will start with some PTFE tape - there is some grip in the thread but not enough to be safe. If not then I will try your excellent suggestion of the epoxy.

I love my fixie but this thing is definitely one for crawling up Gloucestershire hills with 10kg of shopping and 12kg of toddler on board, and I need my granny ring!

mrcharly-YHT · « **Reply #4 on:** 10 April, 2008, 04:51:48 pm »

Sooo - get an M10 bolt?

If you've recut the threads to M10, rather than 10mm fine, maybe a standard M10 will fit?

MSeries · « **Reply #5 on:** 10 April, 2008, 04:52:52 pm »

You'd have to wrangle the bolt out of the mech though. Is that possible ? I don't know.

Chris N · « **Reply #6 on:** 10 April, 2008, 04:53:04 pm »

http://www.sjscycles.co.uk/product-Shimano-Shimano-rear-gear-hanger-bracket--fixing-bolt-420.htm

francisbarton · « **Reply #7 on:** 10 April, 2008, 04:54:37 pm »

Thanks MSeries.
The tap I got was specifically labelled as appropriate for mech hangers. ebay link

border-rider · « **Reply #8 on:** 10 April, 2008, 04:55:36 pm »

Quote from: Fran Barton on 10 April, 2008, 04:51:01 pm

I love my fixie but this thing is definitely one for crawling up Gloucestershire hills with 10kg of shopping and 12kg of toddler on board, and I need my granny ring!

Indeed

This why my trailer-towing trike has lots of dangly bits

scott · « **Reply #9 on:** 10 April, 2008, 04:56:17 pm »

Well, to save the bike you can get one of those rear derailleurs built for bikes without hangers. The derailleur attaches to the dropout with it's own built-in "hanger."

Or get an "adaptor claw" that attaches to the dropout, and has a hanger.

Don't have any UK sources, but:

http://sheldonbrown.com/harris/derailers-rear.html#hanger

Nick H. · « **Reply #10 on:** 10 April, 2008, 04:58:42 pm »

There's always the Emergency Replacement Derailleur Hanger: http://sheldonbrown.com/harris/tools/touring.html

MSeries · « **Reply #11 on:** 10 April, 2008, 04:59:10 pm »

Quote from: Fran Barton on 10 April, 2008, 04:54:37 pm

Thanks MSeries.
The tap I got was specifically labelled as appropriate for mech hangers. ebay link

Ah, well, it seems like you've buggered it then. :-( You probably could use a bolt on hanger like Chris N linked to. That's what I'd try. Actually I'd probably try to make my own first since I (you) already have the tap. Of course I'd redeploy a bit of metal I find on the roadside or salvaged from a washing machine.

scott · « **Reply #12 on:** 10 April, 2008, 05:01:20 pm »

Whoops--sorry, Chris. Didn't see that you had already posted the same idea, and with a more helpful link.

francisbarton · « **Reply #13 on:** 10 April, 2008, 05:02:43 pm »

Cheers Chris and Scott and everyone.
I'll give various measures a try. I'd rather not buy a new rear mech - the bike's not worth throwing money at - but one of those adaptors that you've all suggested would not break the bank.

If it can get it going again I hope to get some "fully laden" pictures posted up here, probably in Kidstuff and/or Member's Bikes.

Polar Bear · « **Reply #14 on:** 10 April, 2008, 05:10:05 pm »

Try this.

scott · « **Reply #15 on:** 10 April, 2008, 05:12:54 pm »

Quote from: Fran Barton on 10 April, 2008, 05:02:43 pm

the bike's not worth throwing money at

Heresy!

mrcharly-YHT · « **Reply #16 on:** 10 April, 2008, 05:16:15 pm »

Hmm.

How did you do the tapping?

It's a bit of an art, keeping the tap square to the hole. Once the tap starts cutting, you do a half turn in, quarter back, half in, etc.

Biggsy · « **Reply #17 on:** 10 April, 2008, 05:31:37 pm »

That Saver Insert looks like an excellent idea.

If you're going to try glue, though, I think epoxy resin would be the best.

Threadlock (red, perhaps even blue) might work if there is some thread left.

Polar Bear · « **Reply #18 on:** 10 April, 2008, 05:33:44 pm »

Quote from: Biggsy on 10 April, 2008, 05:31:37 pm

That Saver Insert looks like an excellent idea.

If you're going to try glue, though, I think epoxy resin would be the best.

Threadlock (red, perhaps even blue) might work if there is some thread left.

Or even Araldite quick steel.

hazeii · « **Reply #19 on:** 10 April, 2008, 05:34:15 pm »

Another possibility would be to use a helicoil - local engineer will do it for you.

Basically it's like a hardened steel spring - you tap the b*****ed hole to fit the outside of the spring, and the inside of it then acts as the new thread.

Normally used for car/motorbike repairs; not heard of one being used to repair a DR bolt before though.

francisbarton · « **Reply #20 on:** 10 April, 2008, 09:59:11 pm »

Quote from: mrcharly on 10 April, 2008, 05:16:15 pm

Hmm.

How did you do the tapping?

It's a bit of an art, keeping the tap square to the hole. Once the tap starts cutting, you do a half turn in, quarter back, half in, etc.

Oh that might be it then

I didn't know that. I just kind of screwed it through. I was happy it was square though.
Ah well, we live and learn.

Thanks PB for you excellent find.
I think glue might work. But if it doesn't then next time I screw up my hanger I'll get one of those

Author Topic: I stuffed up my rear derailleur hanger :-( (Read 6185 times)

border-rider

Chris N

border-rider

Nick H.