omg my rear mech snapped clean off

[Euan Uzami]

on today's audax this happened:



it happened when i was changing gear honking up a hill, i did back off the pressure to let it derail as i always do, I can only think it must have happened 'cos i had just changed front mech as well and I was changing rear before the chain had properly engaged on the granny ring.
Still a bit concerned that an only few months old ultegra mech should just snap though?

fortunately it was near the end and there wasn't too much grimpage still to do - so still managed to make it back singlespeed to some nice soup and tea and 3 and a bit AAAs. (god bless powerlinks!)

[border-rider]

Nasty

I agree - something amiss there.  If it was a bodged gear change - a really bodged gear change - I suppose you might have twisted the cage. But even that would take some doing. 

I've never seen a broken body before.  If the cage didn't go into the spokes then I's suggest a manufacturing fault.

[nuttycyclist]

Chain's a bit slack 



Looks like metal fatigue to me.

[teethgrinder]

  If the cage didn't go into the spokes then I's suggest a manufacturing fault.

Or it's been hit or bent. Aluminium doesn't like being flexed a lot Especialy if it's that thick. It could have had an invisible crack in it.
I see that it's near the hole where the adjuster screws are though, so could have been damaged in production.

[Euan Uzami]

that's what i was hoping - I was wondering whether I might be able to send it back and get a replacement under warranty, but that's a bit of an arse 'cos i want it for the cambrian next weekend! Anyhow i'll find out where i ordered it from and ring them up first thing monday, see how amenable they are...

The other thing i have noticed is that the derailleur hanger now seems bent. My gut instinct is that this caused it to be bent, rather than the other way round - since it was shifting ok, and i know of no incidence of it having been twatted or anything, but it's possible that it's been bent for a while and that may have made it more likely to snap?

The other thing i was thinking is that maybe it's a "best point of failure" - mechanically speaking, it's worse than a broken chain, but if the chain had snapped i would be more likely to have fallen off and got hurt...

Chain's a bit slack  

oh god tell me about it... on the way back into pately bridge i went over a bump which knocked it from 4th (42x19) to 5th (42x17)!   but it was literally only a quarter of a mile so i just though 'i'm moving, that's something...'

Looks like metal fatigue to me.

that would concur, but it's only a few months old...
i'm hanging my hat on MV's idea of a manufacturing fault.

[Euan Uzami]

  If the cage didn't go into the spokes then I's suggest a manufacturing fault.

Or it's been hit or bent. Aluminium doesn't like being flexed a lot Especialy if it's that thick. It could have had an invisible crack in it.
I see that it's near the hole where the adjuster screws are though, so could have been damaged in production.

yes - it is RIGHT on the point of where the low limit adjuster screw goes through.

[valkyrie]

You should definitely get a replacement under warranty. And I would imagine that Shimano would really want to have a good look at what's left of that one. If it's a manufacturing fault (which I think it most probably is) then watch this space for recall notices...

[Euan Uzami]

more pics:

this is the remains of the mech body, notice the two little pins going through it, the left one in this pic goes right through from top to bottom, but the right one looks like it has 'slipped down':



however if i try to move the pins now with my hand, i can't - they are both fixed. There is a little o-ring at either end of both pins, but the one at the top of the pin on the right of this pic isn't there.

now if you notice on this pic which is what was left on the hanger, there are two little dimples - the one on the left of this pic has got a 'gouge' taken out of the top of it - my guess is that this gouge was done by the pin that is now slipped down before it slipped down.


there is obviously another bit that went on the other side of the pins, at the end that the dislodged pin is poking out of - unfortunately it would appear that this bit is laid to rest on a verge somewhere between east whitton and leighton reservoir...

[teethgrinder]

The other thing i have noticed is that the derailleur hanger now seems bent. My gut instinct is that this caused it to be bent, rather than the other way round - since it was shifting ok, and i know of no incidence of it having been twatted or anything, but it's possible that it's been bent for a while and that may have made it more likely to snap?

That's quite a hefty bit of metal to get broken by your rear mech hanger being out of line. Aluminum snaps all of a sudden, whereas steel will give you some warning.
If your hanger is bent, it really suggests to me that something has hit your rear mech very hard, maybe wihout you knowing about it, while you were elsewhere? It has gone next to the adjustment screw hole and that area does look like a weak spot.
I think it's been hit very hard and fractured and that the normal stresses it is put under have finished the job, which was almost done anyway.
Worth getting a new hanger if this one is bent though. Especially if yours is made of aluminium. If it's steel, then you can straighten it out again, but make sure you do a good job of it.

[Biggsy]

I can imagine force from the chain pulling on the mech - while it was busting off at a funny angle - causing the causing the hanger to bend.

Maybe not, though.

[border-rider]

I think TG makes a good point.  The bent hanger isn't likely to be a result of the mech failing spontaneously.  There may be an underlying cause for both...

[MSeries]

A Suntour one did that on me once and I did not have a chain tool with me. A fluffed gear change, kaboom. I hobby horsed to Slough, keeping tension on the top of the chain run and got  a train home. I switched to Shimano SIS, this was in the late 1980s (and I'm still using one of the d/t levers)

[Euan Uzami]

hmmm... i'll take it back to the shop see what they say.
fortunately i got it from the LBS and i've still got the receipt.
bought it in jan so it's about 5 months old.

[Spinners]

Hmmmmm. I'm seriously thinking of switching to Shimano after using Campag since 1994 but this has brought back memories of the only cycling component I've ever broken - a Shimano DX front mech with a fracture not dissimilar to this.

[Zoidburg]

I would take it back.

The aluminium has not been heat treated properly so it has fractured, which makes it not fit for the purpose it was sold for, and unsafe as well.

Be nice about how you put that point across though, you can't expect an LBS to X ray all the stuff before they sell it, Shimano are at fault in the end - but that is between the retailer and Madison.

[SpaceBadger]

I've seen something similar once before when a friend's chain somehow jammed during a low-speed gear change. The bottom half of the rear mech was forced outwards as the chain jammed and twisted. In the absence of a hinge, the mech split in half a bit like the one in the picture.

We just put it down to it being one of those thankfully very rare series of events.

[simonp]

I had a rear mech fail in that way on an old recumbent, when the chain got into a fankle as I wheeled the bike backwards.  Broke the body clean in two.  I was at a feed stop, but the mechanic didn't have a suitable rear mech so I had to finish the ride on one gear.  Bit of an arse on a 'bent, that.  Also the chain kept changing gear.  It was quite predictable too: each time I was going uphill it would move into a higher gear and each time I was going on the flat or downhill, it would change down.  Really hard work but I finished the ride. 

My failure looked very similar to yours so I now wonder if it was a manufacturing fault that allowed it to fail so easily, but this was about 16 years ago and I didn't think of it.

[Euan Uzami]

I would take it back.

The aluminium has not been heat treated properly so it has fractured, which makes it not fit for the purpose it was sold for, and unsafe as well.

Be nice about how you put that point across though, you can't expect an LBS to X ray all the stuff before they sell it, Shimano are at fault in the end - but that is between the retailer and Madison.

That's what i've done, they said that if I need a replacement immediately i'd have to buy one which I did, but that they'd send it back to madison who'll examine it and if they think it's a manufacturing fault rather than damaged by an impact then they'll credit the bike shop who said they'll pass it on to me.

[Polar Bear]

ALERT ALERT ALERT

You have a contract with the shop, not Madison.   Unless it is obvious that you have mis-used the mech the shop are obliged to replace it.   This is your simple rights.   Go and insist on your money back for the second purchase.   If they get stroppy tell them that you're now going to Trading Standards.

Useful reading.   

Naughty retailer.   

[iakobski]

Naughty retailer.   

What the retailer has offered sounds fair to me. I can't see anything in what you linked to that suggests they are not complying.

The retailer probably does not have the skllls or equipment to determine whether the item was faulty, it seems reasonable to send it off for further examination.

[Polar Bear]

It's entirely unfair and it is entirely irrelevant what skills the retailer has.  If you take your borked iron back to Argos do they get a pimply yoof from out the back to take it apart to see what's gone wrong with it?  

Under the law your contract and thus your warranty is with the retailer, not the wholesaler.   The retailer has to repair or replace.   It's a well-used avoidance technique by retailers that they send things to their supplier.

Given that the mech is not very old they must replace it or refund for it.   They then have the issue with Madison for a wholesale refund, not a retail 'inflated price' one.  

It's called your consumer rights.

[Polar Bear]

     Sorry ARO, my rantiness is not aimed at you.   

I'm so fucking pissed off with shitty retailers who still behave as if the law does not apply to them.  I get so many issues to deal with of this type.

 

[iakobski]

I see your point, but it has to be fair to the retailer too. They don't know if the thing broke in normal use or if it was abused. Your iron example is not the same, if something just stops working the retailer can replace and expect their supplier to replace. If the iron had fallen to bits, the retailer would need to check whether it had just fallen to bits while being used for ironing, or if the customer had perhaps thrown it at the wall.

Of course Argos can just replace anything, they are big enough to be able to do that. Independent retailers can't simply refund anything a customer brings back without checking.

Given that the mech is not very old they must replace it or refund for it.

Yes of course they should, mechs should not break like that in normal use. But the retailer needs to check the customer has not broken it through misuse.

I take your point about some retailers, I'm a retailer and we more than comply with the law, we even refund if someone simply decides they don't like something. But we also get the occasional customer who really takes the mickey - we really can't afford to indulge such people as our suppliers certainly won't refund us.

[Biggsy]

I don't think a mech would fail in this particular way even from misuse if it was manufactured properly.  To sheer right off like that doesn't look normal, does it?

[Polar Bear]

With respect ARO, being a retailer you should know what teh legal obligations of a retailer are.   I appreciate that there is a difference between perception of reasonableness and the law, but your perspective is that of the retailer.   If the role was reversed you'd want to have your faulty goods replaced rather than wait.  No?