Rear Hanger Broke

Cee-Jay-Cee · 19-09-2019 11:31am #1

I was out for a cycle yesterday on my Felt VR30. After about 30km I could feel and hear a click while in the upper/bigger sprockets on the cassette and it got worse the lower the gear so when in the biggest pn the rear it was at its worst. I thought it was the BB as I could physically feel a slight pull each time it clicked as if the crank was spinning out of true. Anyway I stayed out of the bigger sprockets as much as possible and continued on home. My house is at the top of a steep ramp/hill of about 300m long and 14% gradient and I didn't want to grind up it in a higher gear so I put it in the big/big combo (30/32) and spun up as easy as I could all the time listening to the creaking and feeling it in the cranks. Anyway about 100m up, there was a crack and I instantly stopped and clipped out and looked at the RD which was bent upwards and stopped short of catching in the spokes.

I walked the last few hundred meters home and inspected the bike. The RD hanger had broken at the threaded section where the RD screws into leaving a semi-circle piece of metal still attached to the RD. I could see that the rest of the hanger was bent outwards. The chain was also kinked and one of the link had popped off the pin. Thankfully I was going so slow/easy that it didn't catch and shred any spokes.

So I removed the RD which is a 5800 long cage and it appears that the cage section/arm is bent. I have three other bikes and theyre all shimano groupsets and I was inspecting the RD on each of them and the arm appears to be straight with no bend on any of them but theyre all short cage RDs and so i'm unsure if the arm should be slightly bent or not. If its supposed to be straight then I can only assume the hanger breaking and the RD being twisted upside down caused the arm to bend.

Anyway I've ordered a new rear hanger (x 2, bought a spare just to have) a new chain as I binned the old one and a new R7000 RD but I cant figure out what happened to cause the hanger to break in the first place. Is there any thing I should be looking at as a possible reason as to why the hanger might have broken?

cdaly_ · 19-09-2019 11:42am

Could have been a fall, could have got a bash from somebody parking their bike, could be just a flaw in the hanger.

magicbastarder · 19-09-2019 11:44am

you were just putting out too much power for it.

Cee-Jay-Cee · 19-09-2019 11:51am

magicbastarder wrote: »

you were just putting out too much power for it.

That's what my wife said and then broke down in uncontrollable laughter.

19-09-2019 1:01pm

Had you been quick enough you could have put a stop to your wife's laughter by explaining that this failure warranted a new bike

Cee-Jay-Cee · 19-09-2019 2:05pm

Deleted User wrote: »

Had you been quick enough you could have put a stop to your wife's laughter by explaining that this failure warranted a new bike

Ha ha yeah that would have fairly shut her up!! But as I already have 4 bikes, I cant use the excuse that I have no bike now until this one gets repaired.

magicbastarder · 19-09-2019 2:10pm

maybe it was the chain which failed first?
i.e. a link could have opened, and fouled in the RD as it went through, so if you're pedalling on an uphill, that link could have fouled the RD at the bottom and pulled it upwards?

cdaly_ · 19-09-2019 2:56pm

That sounds quite plausible. I killed an RD by continuing to use a very worn chain. Taking off from a traffic light while changing down to the small ring and the RD got caught up in the spokes. I suspect the chain slapping around under tension and change down was responsible.

Cee-Jay-Cee · 19-09-2019 7:25pm

Yeah I am veering towards it being chain related too. The chain was fairly new, maybe 700-800kns on it but that’s not to say it didn’t fail or got damaged somehow.

Anyway I hope that when the new parts are fitted that everything works as it should again.

magicbastarder · 19-09-2019 7:34pm

the fact that the chain was kinked might be consistent with the chain being at fault?
are there any marks on the RD where the chain would enter at the bottom consistent with that possibility?

Cee-Jay-Cee · 19-09-2019 10:06pm

magicbastarder wrote: »

the fact that the chain was kinked might be consistent with the chain being at fault?
are there any marks on the RD where the chain would enter at the bottom consistent with that possibility?

I just went out to have a look and yes there are marks consistent with something catching on it so I’m guessing the chain was at fault and caused the whole thing.

You can see the marks on the cage where the chain was obviously running against the side for whatever reason.

Rear Hanger Broke

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