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Shimano Ultegra 6800 Crank arm (53-39 172.5) snapped

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  • 23-03-2022 9:27pm
    #1
    Registered Users Posts: 8


    Hi everyone,

    Just wondering if anyone out there has a similar crank arm or crank set for sale (new or used) that would suit my bike {Shimano Ultegra 6800 Crank arm (53-39 172.5)}? .Photos attached.


    I was out for the first spin of the year today and snapped the crank arm. Weather is looking great for the weekend so I'd love to get out for it. Any help much appreciated. I'm based in Waterford.


    Thanks a mil!

    Regards,

    James.





«1

Comments

  • Registered Users Posts: 2,281 ✭✭✭Mercian Pro


    As Wishbone Ash and myself discovered on the same spin last December, Ultegra cranks have a habit of cracking usually as a result of the glue fixing the two sides failing over time. WA's R8000 was promptly replaced by Humphries but my 6800 was well out of the two-year warranty. I replaced it with a 105 crankset (no glue involved) from Bike 24 that arrived within a couple of days and have been using it since then. Madison, the Irish & UK Shimano agents, have since agreed to replace the broken one but I am still waiting for it to arrive so I'm afraid I can't help you. If you bought originally from a LBS, they might be able to look after you.



  • Registered Users Posts: 5,829 ✭✭✭fat bloke


    Snap! Literally! Just 20 mins ago I had a whatsapp conversation with a mate who's ultegra crank did the exact same thing today. There's a fair bit on Google about it affecting the hollowgram/hollowtech chainsets. It's not uncommon.



  • Registered Users Posts: 8 buckmulligan




  • Posts: 0 [Deleted User]


    105 is probably about €100 cheaper and a few grams heavier. So more for less!!!!! 😂

    Looks to be some wear at least on your chain rings no? So maybe a good idea to do the lot. Just double check the BB compatibility but I think they are the same.

    EDIT: Just watch out on the one you've linked to they are 50-34 and only available in 170 and 175 lengths.

    Chain reaction have the 105 in 53/39 172.5



  • Registered Users Posts: 1,493 ✭✭✭hesker


    Cripes that looks very new. 2 year warranty on these is a joke. Tons of online exposes of the poor design of these. Even hambini has got in on it



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  • Registered Users Posts: 333 ✭✭Exiled1


    Mine snapped last year in much the same place. My lbs told me they had seen several similar breaks, but never saw a 105 breaking.

    I replaced it with a 105, happy days.

    Hope you can source one.... they are scarce.



  • Registered Users Posts: 4,587 ✭✭✭MojoMaker


    105 is as tough as nails alright. My only criticism of 5800 is that the Matt black paint scuffs quite easily and can look pretty tired quickly. To my eye R7000 looks better if you can find one!



  • Posts: 0 [Deleted User]


    R7000 in stock on Chain Reaction in the OP's configuration for €157



  • Registered Users Posts: 2,281 ✭✭✭Mercian Pro


    Decided on the 105 as they are a forged single piece with no record of failures. Mine was €124 plus €10 p&p from Bike24. Given that a single Ultegra chairing is generally over €100, I reckoned it was a good price. Bought a few other consumables like chains, cassettes and bottom brackets while I was at it.

    I haven't seen anything yet about the design of the cranks on the new Ultegra R8100. Officially they are still in denial about the problem with the 6800 and R8000 so even if they have sorted out the issue, they may not want to publicise it.



  • Registered Users Posts: 8 buckmulligan


    Thanks for all the advice everyone. I took your advice and went for a 105 in 52/36 172.5 from chain reaction. Won’t be out this weekend but should have it sorted soon 🤙 Thanks again. Safe riding to you all



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  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,676 CMod ✭✭✭✭magicbastarder


    i'd be curious as to how many cranksets have failed. if as mentioned by Exiled1, a bike shop had seen 'several' break and presumably they might have sold X hundred bikes, it could be 'just' a couple of percent.



  • Registered Users Posts: 852 ✭✭✭gn3dr


    Yeah but surely the goal is zero percent. I never really heard of crank sets failing like this on the older forged stuff. But there is a lot of internet chatter about the 6800 stuff. I'm still on Dura Ace 7700 & 7800 on 2 bikes and even looking at them I'd have no fear about them failing. But when glue etc come into the equation (even though these look like fatigue failures as opposed to glue) then you have to wonder if the weight / durability line was crossed.



  • Registered Users Posts: 1,493 ✭✭✭hesker


    I’ll be none too happy if I end up in that grouping of “just” a couple of percent.

    Would be interesting to compare it to the failure frequencies of single piece models of cranks.

    I don’t buy the argument that the customer bought into this limited lifetime in the pursuit of weight saving spiel that is floating around. There should be an expectation of a certain lifetime based on previous models. Begging for a class action lawsuit in my mind.



  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,676 CMod ✭✭✭✭magicbastarder


    that's why i put just in inverted commas, FWIW.



  • Registered Users Posts: 4,587 ✭✭✭MojoMaker


    R7000 is a good looking crank - good choice I think.



  • Registered Users Posts: 1,493 ✭✭✭hesker


    Older solid alloy cranks did fail occasionally but the failure mode is completely different. They usually failed at the pedal eye or at the spider. And I have the impression it was rare enough and not within a few short years although I’ve never seen any stats.

    Would be good to see the numbers on these but I’d say Shimano are guarding those very tightly.



  • Registered Users Posts: 934 ✭✭✭nicksnikita


    The day of the cover up is well and truly gone.

    There’s a Facebook or Instagram page keeping a record of reported crank failures. I haven’t been on the page myself but from memory it’s called something like “Thanks Shimano”



  • Registered Users Posts: 2,281 ✭✭✭Mercian Pro


    #thanksshimano on Instagram. Plenty of analysis/speculation on the cause if you Google it with most of the online cycling sites covering it. The general view seems to be that the glue bonding the two halves breaks down over time if moisture gets into the crank. Once this happens, a lot of the strength of the cranks is lost. It seems to be most common in areas of high humidity such as Florida and parts of Asia.



  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,676 CMod ✭✭✭✭magicbastarder


    interesting - i have ultegra on the good weather bike, so i guess that means i shouldn't worry so much.



  • Registered Users Posts: 1,493 ✭✭✭hesker


    Our old friend galvanic corrosion raises it’s head again. Corrosion first then debonding due to the expansion. That’s hambini’s take on it anyway and in fairness he does a pretty good analysis.

    Promoted by high humidity/ wet / salty roads. But arising first from the use of a steel axle with aluminium cranks.

    Given Irish climate is quite humid, winter cycling on damp/wet roads should be problematic.




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  • Moderators, Sports Moderators Posts: 19,985 Mod ✭✭✭✭Weepsie


    Nearly had me watch a video by a complete arsehole til I copped it was him



  • Registered Users Posts: 1,493 ✭✭✭hesker


    Do his vids have to come with a warning now. His name was there in the text for you to see.

    Whatever about his persona and delivery which is fairly out there his analysis is pretty spot on. Most people mute the first 10 secs it seems



  • Registered Users Posts: 1,722 ✭✭✭Large bottle small glass




  • Registered Users Posts: 1,493 ✭✭✭hesker


    Had not seen any of that before



  • Posts: 0 [Deleted User]


    There was another one he had a go at, over riding during early lock down or am I recalling that correctly?

    EDIT: It was probably the same lady mentioned above.



  • Moderators, Sports Moderators Posts: 19,985 Mod ✭✭✭✭Weepsie


    Some of it is ott. He's got enough jargon, general knowledge and sales patter to make people think he has the answer and anyone who disagrees is wrong.. at the end of the day, he's really trying to sell his products. He's not trying to improve bb standards.


    Mainly thought, at the the end of the day, he was shown up to be a contemptible arsehole


    no there's nothing in the embedded video for me as I see it to tell me who it is. Might be my devices.



  • Registered Users Posts: 1,493 ✭✭✭hesker


    I didn’t claim there was just pointed out I had referred to his name in the text.

    But it would be good to know if this is a requirement now for videos in general. Equally how is someone to know that there is a prior history associated with a particular content producer that makes it unpalatable for viewers in this forum. I don’t think the charter covers it.



  • Registered Users Posts: 1,722 ✭✭✭Large bottle small glass


    Why should there be a problem posting his videos? Because he is a registered cnut doesn't make him technically wrong; people can chose because of his registration not to click.



  • Registered Users Posts: 1,493 ✭✭✭hesker


    That’s a fair question. I’m just reacting to the accusation I nearly had someone do something they didn’t want to do like I held a gun over their head or something.



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  • Registered Users Posts: 2,281 ✭✭✭Mercian Pro


    No idea what the problem/backstory with hambini is and I'm not pushed about researching it so don't need links. That video on the Dura Ace crank failure seems spot on both from my experience of Ultegra crank failure and my distant memory of chemistry lectures in Bolton Street. It also explains some of the issues that came up in other articles I'd read and ended with a recommendation that you switch to a 105 crankset which is exactly what I did. Mind you, I'm still waiting for my replacement cranks from Madison even though I have an email from them saying they would!



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