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

buckmulligan · 23-03-2022 08:27PM #1

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.

Mercian Pro · 23-03-2022 09:45PM

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.

fat bloke · 23-03-2022 10:07PM

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.

buckmulligan · 23-03-2022 10:24PM

Many thanks for the reply Mercian Pro. It must be a design flaw I reckon. So you would recommend shimano 105 groupset then? What do you think of below?

https://www.wiggle.co.uk/shimano-105-r7000-11-speed-compact-chainset?lang=en&curr=EUR&dest=6&sku=100633904&utm_source=google&utm_term=&utm_campaign=&utm_medium=&gclid=CjwKCAjwiuuRBhBvEiwAFXKaNO3e-NF8YQNG3UjicSbrCBg0QlZSQQKEhhg5KgXTS0fbfsrN1HSjUxoCiOAQAvD_BwE&gclsrc=aw.ds

23-03-2022 10:33PM

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

hesker · 24-03-2022 12:59PM

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

Exiled1 · 24-03-2022 01:47PM

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.

MojoMaker · 24-03-2022 04:34PM

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!

24-03-2022 04:46PM

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

Mercian Pro · 24-03-2022 07:00PM

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.

buckmulligan · 25-03-2022 05:59PM

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

magicbastarder · 25-03-2022 08:04PM

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.

gn3dr · 25-03-2022 11:27PM

https://www.boards.ie/discussion/comment/118835962#Comment_118835962

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.

hesker · 25-03-2022 11:39PM

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.

magicbastarder · 25-03-2022 11:43PM

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

MojoMaker · 26-03-2022 10:03AM

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

hesker · 26-03-2022 10:10AM

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.

nicksnikita · 26-03-2022 10:20AM

https://www.boards.ie/discussion/comment/118837838#Comment_118837838

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”

Mercian Pro · 28-03-2022 07:45PM

#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.

magicbastarder · 28-03-2022 07:54PM

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

hesker · 28-03-2022 10:55PM

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.

https://youtu.be/-uK7FSZ6OFM

hesker · 29-03-2022 08:00AM

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

Large bottle small glass · 29-03-2022 09:51AM

https://www.boards.ie/discussion/comment/118850088#Comment_118850088

https://www.boards.ie/discussion/comment/118724417#Comment_118724417

Link in post for Mefistofelino isn't pleasant reading.

hesker · 29-03-2022 12:45PM

Had not seen any of that before

29-03-2022 06:24PM

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.

hesker · 30-03-2022 09:52AM

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.

Large bottle small glass · 30-03-2022 10:17AM

https://www.boards.ie/discussion/comment/118855178#Comment_118855178

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.

hesker · 30-03-2022 12:03PM

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.

Mercian Pro · 30-03-2022 02:06PM

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!

slow · 30-03-2022 02:55PM

I experienced a wonky driveside pedal which turned out to be a crank about to shear completely about 50mm from the pedal. Less than 2 years old...

hesker · 30-03-2022 03:19PM

For anyone who has suffered similar failures outside the 2 year window it might be worth getting in touch directly with Shimano. They might provide support where an LBS may not.

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

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