Damage to rear derailleur after fall, advice needed

skr88

I came off my bike on my way home from work, checking over the bike after I got home, looks like there's some damage to the rear derailleur (was only my second ride on it D'oh!)

I'm not clued up on components, or what they're supposed to look like but something doesn't seem right, looks like its probably bent. Do I need to replace anything or can I bend it back?

Edit: Sorry, not sure why the pics have been have been rotated.

iPete

In the last picture you can see that the rear hanger is bent, hopefully just that. You can straighten your derailleur hanger yourself (at own risk, there are specialist tools for this). I bent a mates back with an allen key and some brute force*

http://www.parktool.com/blog/repair-hel ... -alignment

If the bike is a common model(?), finding a replacement might be the cheapest option vs getting a shop to re-align.

*do not try this at home etc.

skr88

So if I were to bend it back, Its best to use an allen key to loosen it first?

It's a Fuji Tread 1.3, which has Shimano Sora derailleur I believe.

bob6397

My LBS bent a hanger back for me a couple of months ago for under £5..

From the pics though it may be the actual derailleur cage that has bent as well..

Can you take the derailleur off the bike and lay it on a flat surface to see if that has bent as well?

And yes, if you want to bend it back yourself (be VERY careful as you may snap it/warp the thread if you do it wrong) then I would take the derailleur off the bike but leave the hanger attached to the frame..

skr88

bob6397 wrote:

My LBS bent a hanger back for me a couple of months ago for under £5..

From the pics though it may be the actual derailleur cage that has bent as well..

Can you take the derailleur off the bike and lay it on a flat surface to see if that has bent as well?

And yes, if you want to bend it back yourself (be VERY careful as you may snap it/warp the thread if you do it wrong) then I would take the derailleur off the bike but leave the hanger attached to the frame..

Hmm, LBS might be the better option here. I think it's the red part (bottom pic) which is bent, causing the hanger to be jutting off to an angle...

bob6397

I agree that the hanger is definitely bent. Whether the cage (the bit with the jockey wheels in hanging off the bottom of the derailleur) is also bent I can't tell.. It looks like it might be from the bottom pick though..

LBS is your best bet if you are in the least bit unsure..

iPete

skr88 wrote:

So if I were to bend it back, Its best to use an allen key to loosen it first?

It's a Fuji Tread 1.3, which has Shimano Sora derailleur I believe.

No and I wouldn't recommend that! I would recommend the LBS route.

But if you are intrigued, post two covers the allen key method..
http://www.bike-air.com/Derailleur-hang ... 98285.html

skr88

bob6397 wrote:

I agree that the hanger is definitely bent. Whether the cage (the bit with the jockey wheels in hanging off the bottom of the derailleur) is also bent I can't tell.. It looks like it might be from the bottom pick though..

LBS is your best bet if you are in the least bit unsure..

Ah sorry, so that red part is the hanger. Gotcha. Yep, I think I'll pop up to the LBS (once my arm has healed :roll: ) and see what they say. Thanks for the advice gents.

Bobbinogs

Hangers are usually made of aluminium and that is one material that doesn't like to be bent. The probability is that it will crack in some way (visible or not) which may then fail at some point, possibly when it is not too convenient. Personally, I would just replace the hanger as they usually cost about 20 quid and take about 5 minutes to swap.

skr88

Bobbinogs wrote:

Hangers are usually made of aluminium and that is one material that doesn't like to be bent. The probability is that it will crack in some way (visible or not) which may then fail at some point, possibly when it is not too convenient. Personally, I would just replace the hanger as they usually cost about 20 quid and take about 5 minutes to swap.

Okay, do I need to buy a specific size or anything?

sungod

the hanger matches the frame, there are umpteen types, you may be able to get one from one of the several online sources, for instance...

http://gearmechhanger.com/

or a fuji bike dealer may have stock, otherwise it can be ordered from the distributor (may or may not need to get lbs to do this)

964cup

Bobbinogs wrote:

Hangers are usually made of aluminium and that is one material that doesn't like to be bent. The probability is that it will crack in some way (visible or not) which may then fail at some point, possibly when it is not too convenient. Personally, I would just replace the hanger as they usually cost about 20 quid and take about 5 minutes to swap.

He'll still need to get a hanger tool on it, since the frame is unlikely to be perfectly straight (few are), so the hanger will need aligning.

skr88

sungod wrote:

the hanger matches the frame, there are umpteen types, you may be able to get one from one of the several online sources, for instance...

http://gearmechhanger.com/

or a fuji bike dealer may have stock, otherwise it can be ordered from the distributor (may or may not need to get lbs to do this)

Cheers, that link is very helpful.

964Cup wrote:

He'll still need to get a hanger tool on it, since the frame is unlikely to be perfectly straight (few are), so the hanger will need aligning.

Once I have the part, I'll probably take it up to the LBS and have them fit/align everything properly. Will most likely end up getting one of those alignment tools at some point in the future though.

blackpoolkev

P.S. In the meantime, if you feel like riding your bike - DO NOT change the derailleur to the large cog. Chances are that the mech will say hello to the spokes of your back wheel. This scenario doesn't end well.

bob6397

I would advise against riding it at all with a bent hanger. And there is nothing wrong with bending one back if you do it right - your LBS (if decent) will know how. Hanger's are there to bend after all.

And if you do want to get a new one, I recommend going to ask your LBS (they may even have the correct one in stock - long shot though) as they will be able to tell you if it's the right one exactly.. Otherwise I got a black CNC'd one off ebay for £20 lately for my mtb after someone ran into the back of my derailleur (long story) - I bent it back to get me the 20 (careful) miles home and then replaced it myself.

My LBS bent back the one on my road bike back in November and now, a couple of hundred miles later, it is still fine.. No sign that it is even thinking about going..

skr88

blackpoolkev wrote:

P.S. In the meantime, if you feel like riding your bike - DO NOT change the derailleur to the large cog. Chances are that the mech will say hello to the spokes of your back wheel. This scenario doesn't end well.

:shock: Duly noted.

bob6397 wrote:

I would advise against riding it at all with a bent hanger. And there is nothing wrong with bending one back if you do it right - your LBS (if decent) will know how. Hanger's are there to bend after all.

And if you do want to get a new one, I recommend going to ask your LBS (they may even have the correct one in stock - long shot though) as they will be able to tell you if it's the right one exactly.. Otherwise I got a black CNC'd one off ebay for £20 lately for my mtb after someone ran into the back of my derailleur (long story) - I bent it back to get me the 20 (careful) miles home and then replaced it myself.

My LBS bent back the one on my road bike back in November and now, a couple of hundred miles later, it is still fine.. No sign that it is even thinking about going..

I think for the £20 and peace of mind I'll just replace it, knowing my luck It probably won't be the last time I fall off and wouldn't want it to snap or anything if that were the case. Thanks again for the advice.

wishitwasallflat

My hanger snapped last week, destroyed spokes and dérailleur = very expensive. Yourse is badly bent don't ride that bike until it's been replaced. Mine cost £10 and I fitted it myself with new dérailleur, works fine. I've fitted several dérailleur and hangers and never used nor needed an alingment tool.

Tjgoodhew

I bent mine when my bike toppled over in the wind. It was only a small bend but affected the rear indexing.

Took the bike to LBS and they bent it back but did advise getting it replaced as you never know how much the material would have weakened by being bent.

Cost me £17 for a new hanger and paid the LBS £6 to swap it - i could of done it myself but for the sake of £6 though i would leave it to them.

Small price to pay really as if the thing fails then it knackers an expensive real wheel and RD

frogdr1ver

I had to replace my rear hanger after the weekend incident, I got it from these guys http://www.ebay.co.uk/itm/REAR-MECH-GEAR-DERAILLEUR-HANGER-FRAME-DROP-OUT-BRACKET-VARIOUS-BIKE-CYCLE-/300965102296?pt=LH_DefaultDomain_3&var=&hash=item4612eb02d8 exactly the same as the one I paid over double for from a well known online shop. For the record I have no affiliation etc with them just impressed with the quality and price.