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Re: FAILURE Shimano Cranksets

Posted: Mon Jan 23, 2017 5:07 pm
by nickf
wheelsONfire wrote:It seems this is due to corrosion, humidity and salt?
Perhaps in conjunction with a twisting load when we pedal it work itself off or in some cases crack?

So Shimano Hollow Technology is bascially a U-profile with a reversed U-profile glued on?


Its humid here in Orlando for sure but no salt water to worry about this far inland. The customer lives and rides in the central florida area. The glue on the inside was dry and chalky. This is a recreational rider.

Re: FAILURE Shimano Cranksets

Posted: Mon Jan 23, 2017 5:07 pm
by Weenie

Re: FAILURE Shimano Cranksets

Posted: Tue Jan 24, 2017 1:17 am
by PedroS
I wonder just how wide spread this really is. Is it design flaw or just a bad run of cranks? I just purchased a full 6800 group hang on a new Ti frame and now I'm wondering if I should for forego the crankset and find a nice 6700 crankset on eBay.

Re: FAILURE Shimano Cranksets

Posted: Tue Jan 24, 2017 1:38 am
by moonoi
I dunno but here in Thailand there seems to be an increasing number of failures, this happened to one of our club members a few weeks back, Shimano swapped it out under warranty. Failed after just 2000km/5 months.

I just got a new Ultegra crankset on my M9 and quite worried about whether it is going to fail.

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Re: FAILURE Shimano Cranksets

Posted: Fri Mar 09, 2018 9:52 pm
by RDorna
Ultegra 6800 Crank failure? I have a private collection! 8) The fist one I threw in the trash. Should be 7, not ONLY 6... SHOULD BE A SMILE FACE WITHOUT TEETH TOO

Re: FAILURE Shimano Cranksets

Posted: Sat Mar 10, 2018 8:16 am
by MyM3Coupe
It’s a raging failure. I’m in the US and have seen this on several peoples Ultegra cranks. Shimano needs to do a recall or get badly sued when someone gets hurt.

Re: FAILURE Shimano Cranksets

Posted: Sat Mar 10, 2018 8:53 am
by alcatraz
I don't remember my chemistry very well but it could be possible that something has started a corrosion between the two bonded pieces. Maybe a foreign element creating a galvanic cell. I would clean it thoroughly and apply a light layer of oil or thin grease. Polish that baby up after.

I recently got a cheap sisl2 crank which are two bonded alloy pieces and I did notice that corrosion had attacked it and started getting inbeteen the bonded layers. This is not good. I took some oil on a rag and wiped the crank down. It was bone dry and looked rather dusty when I got it. Probably a result of leaving it in a damp and dirty place without any previous treatment for a longer time.

/a

Re: FAILURE Shimano Cranksets

Posted: Sat Mar 10, 2018 5:41 pm
by Geoff
:shock:

Re: FAILURE Shimano Cranksets

Posted: Thu Apr 19, 2018 2:29 pm
by NJCyclist
Is there any information on the prevalence of these failures? I have a 6800 crank on one of my bikes and I'm a big rider, putting a lot of force through the cranks. Would it be prudent to move away from the Ultegra crank?

Re: FAILURE Shimano Cranksets

Posted: Thu Apr 19, 2018 5:02 pm
by wingguy
Having worked in a large, road oriented bike shop through the entire 6700, 6800 and now 8000 eras of ultegra I have never seen an Ultegra crank failure, or even any incipient signs of this kind of failure.

Just think how many of these cranks are out there. It and 105 are far and away the most popular ‘race level’ cranks in the world. Even if there are quite a few documented failures the rate of occurrence is still vanishingly small, IMO.

Re: FAILURE Shimano Cranksets

Posted: Thu Apr 19, 2018 6:57 pm
by NJCyclist
I figured the failure rate was quite low. I suspect it's not a design flaw but instead a bad batch made with bonding compound that wasnt' to spec.

Re: FAILURE Shimano Cranksets

Posted: Thu Apr 19, 2018 11:07 pm
by 2lo8
wingguy wrote:
Thu Apr 19, 2018 5:02 pm
Just think how many of these cranks are out there. It and 105 are far and away the most popular ‘race level’ cranks in the world. Even if there are quite a few documented failures the rate of occurrence is still vanishingly small, IMO.
Pretty sure 105 use the tube-pinched-shut-at-the-pedal-eye-end construction of older hollowtech cranks at least up through 5800, which could explain it. I don't have 5800 anymore, but I remember checking and noting that it did not appear to have bonded construction. 6700 for that matter too. I think the bonded cranks are 9000 and 6800 onwards. This bonded construction saves all of 20g(?) between 5800 and 6800 arms.

Re: FAILURE Shimano Cranksets

Posted: Fri Apr 20, 2018 6:23 am
by shotgun
My 6800 crank failed on me 2 weeks ago. Similar issue that the top portion of the crank split. Adhesive failure I guess. Good thing I was less thatn 5km from my car. I thought it was a loose cleat since my right heel would brush against the chaistay.

I've had the crankset for 2 years, 80% of the time it's used indoors. I don't produce loads of watts, but I figure that having it strapped to a trainer increases crank stess.

Re: FAILURE Shimano Cranksets

Posted: Fri Apr 20, 2018 6:28 am
by shotgun
NJCyclist wrote:
Thu Apr 19, 2018 2:29 pm
Is there any information on the prevalence of these failures? I have a 6800 crank on one of my bikes and I'm a big rider, putting a lot of force through the cranks. Would it be prudent to move away from the Ultegra crank?
Myself and another training buddy had our 6800 crank fail on us. We're both under 70kg and shell out low watts (under 300 FTP I reckon).

Re: FAILURE Shimano Cranksets

Posted: Sat Apr 21, 2018 4:06 pm
by XCProMD
ImageImage

I’ve found these with a quick search on my mobile (can’t find my own DA though) but I’ve seen - heard of dozens of cases.




Inviato dal mio iPhone utilizzando Tapatalk

Re: FAILURE Shimano Cranksets

Posted: Sat Apr 21, 2018 4:06 pm
by Weenie

Re: FAILURE Shimano Cranksets

Posted: Sun Apr 22, 2018 4:19 pm
by wheelbuilder
wingguy wrote:
Thu Apr 19, 2018 5:02 pm
Having worked in a large, road oriented bike shop through the entire 6700, 6800 and now 8000 eras of ultegra I have never seen an Ultegra crank failure, or even any incipient signs of this kind of failure.

Just think how many of these cranks are out there. It and 105 are far and away the most popular ‘race level’ cranks in the world. Even if there are quite a few documented failures the rate of occurrence is still vanishingly small, IMO.
Interesting. I also work in a road oriented shop only a couple days a week, and I have seen four.