ljsense

The exterior is painted and clear coated, and the steel spindle is not exposed, so in practice I don't think there is much risk from incidental water contact that is not inside the crank.

Once inside, though, it stays and is touching uncoated metal to create the battery.

Shimano made a longer plastic preload bolt to seal up that end of the spindle. So maybe this was a frequent way water gets in -- through the spindle.

Kontact 

Atmospheric pressure changes are going to put condensation anywhere that isn't airtight, and the spindle has a hole in the side of it.

Polaris OBark

That part is either inside the crankset, or inside of the bottom bracket/crankset seal.

Kontact 

Say what?


That lines up with the split in the crankarm for tightening, and is inside of where the end cap goes. It isn't remotely sealed.

But that tube is capped on the driveside, if that's what you mean. However, Hambini points out that the thin edges are bonded in such a way that pin hole leaks are likely. It really takes so little water to allow the corrosion to start.

Polaris OBark

The other thing is that only the Dura Ace and Ultegra cranksets have been recalled. Assuming that is the scope of the problem, it strongly suggests the problem is with the hollowtech assembly, and not what the filthy fingernail is pointing at.

Lombard

Exactly. 105 is not affected.

Kontact 

Of course. The point isn't that galvanic corrosion is always going to lead to failure, but that certain types of construction can't tolerate it.

Just like a carbon tubes with uninsulated aluminum lugs are going to have bonding failures in a carbon frame, the bonds holding together the upper end HT cranks are similarly vulnerable. And like lugged carbon frames, there is likely a construction solution that would prevent this kind of corrosion leading to a bonding failure.

If HT cranks had 29mm aluminum spindles instead of steel, for instance, then there likely would not be any corrosion.

choddo

although the steel bearing could be an issue if water got in with the axle.

I think you do need a reasonable amount of water to cause this because in air the aluminium forms a thin oxidised protective layer and it’s the presence of the electroyte on the outside of that layer, and in contact with the cathode/steel which causes the ions to break through that layer and cause the damage.

Polaris OBark

If the GRX and 105 and numerous similarly-designed mountain cranks that Shimano makes aren't failing, the question is why the Dura Ace and Ultegra cranks?

The answer is most likely where they differ: The two-piece hollowtech construction.

I wonder if the glue that bonds them together conducts, or at the very least is permeable to water (or maybe absorbs water)?

Welshboy

One of my bikes is all 11-speed Dura Ace except for the chainset and I've been keen to replace it... not now though!

scottfsmith

I have two R8000s in this period but I barely missed recalls on both -- they both start with S and it stops at R. Whew!

Lombard

Exactly this.

Polaris OBark

Since they did everything they could to dodge this recall, I wouldn't breathe that sigh of relief just yet.

bblair

Are the new Ultegra cranks vulnerable as well? 105 is probably not that different, but I hate to take a step down if I don't have to.

Still, as I understand it, 0.6% of cranksets have been at least reported. Pretty good odds. I hope.

(But how many not reported?)

Lombard

105 is one piece construction, not two piece, which is why it's not affected by this recall. It weighs a bit more, that's all.

choddo

No. 12 speed not affected (and in fact is what you get as a replacement) but no one is certain why.

0.6% the feds know about. It’s much higher. Having said that, my circa 2013 FC6800 is fine.

Eddy_G 

One of my jobs is working at a dealership, and I have completed the S-Tech training modules in regard to this set of recall procedures.

When you bring a bicycle in for the recall, there is first a check of the date code and a Safety Notice Quick Evaluation. This is the sort of inspection that we should all do regularly, not just after we hear an odd noise. Wipe it clean and give it a good visual on-the-bike inspection. I use a bright flashlight as well.
If the crankset is at all in question, then it will move forward to the Safety Notice Complete Inspection. This is much more detailed and involves removal, disassembly, and thorough cleaning before further visual inspection.

Regardless of date code, Left-side Ultegra crank arms do not need to be inspected. Dura-Ace cranks that are etched with an effected date code should have both arms inspected.
Once a crank with an included date code has been determined by the complete inspection to show any symptoms or signs of the problem, the inspection has been fully documented, and a claim has been filed, the effected crank(s) will be shipped back to Shimano for further inspection and verification before replacement(s) will be sent by Shimano.
Cranks that are equipped with 3rd-party power meters (including Pioneer) will be replaced with cranks that do not have a power meter. Shimano will provide the consumer with a check, based on the power meter's configuration, that can be used toward adding a power meter to their crankset. (Their words, not mine)

Please try to remember that I am not an employee of Shimano.
I just work in a small shop right now, and we aren't any happier about this situation than you probably are.
In the northern hemisphere, it's the busiest part of the year for many service departments, and this recall is a truckload of straws on the backs of some already very hard working camels.
Any good dealership will do what is within their power to take care of your inspection a.s.a.p.
The last thing anybody wants is more bikes in limbo taking up space in the shop and fewer on the road, so please try to be patient with your LBS.

I thought that some folks might find that information useful. If you still have questions, don't hesitate to contact your LBS.
Good luck, and Best Wishes.

10/1/2023: Update.
Yesterday, we received a new notice from Shimano regarding inspection procedures.
From Shimano USA - "Since releasing the training modules about the recall, we’ve received a lot of great feedback from the S-TEC Community.Based on that feedback we wanted to outline some key points to remember:

• All effected cranksets require a complete inspection (revised module)
• Consumers should stop riding their effected cranksets until a "complete inspection" can be completed
• Retailer should only perform “complete inspections”, not “quick evaluations”
• A complete inspection requires the crankset to be removed from the bike and disassembled"

choddo

Thanks

Any clue given how long that turnaround will be?

A cheque as in an actual physical piece of paper? Or is that just a convention for “some financial compensation”?

Bike Gremlin

I find the shape of those cranks to be designed for looks more than the strength or stiffness.

Circular cross-section or as close to it as reasonably possible would probably work better (but sell worse, 'cause it doesn't look cool & "aero").


Shimano Hollowtech II crank cross-section


In the meantime, the pedal-to-crank interface is what no manufacturer considers improving:


Jobst Brandt's improvement of the pedal-to-crank interface

This would allow for both the left and the right hand pedals to have a standard (right-hand) thread, and prevent fretting damage and cracks of the cranks.
Would that make things easier for everyone in the long run? I think so.

Relja Novovic

bblair

Oh.

I was hoping that my LBS could just swap me a new one and off I go.

​​​​​​​In my part of the world, the cycling season would likely be over by the time this happens.

tiger1964 

I have a friend who is overseas right now and will have to inspect his bike upon return. About 90 days ago, an infuriating clicking sound from his Shimano cranks revealed a crack and it was replaced at my friends' expense. One presumes the bike shop discarded the cold cranks and my friend is out of luck. Sheesh.

Meanwhile, on every ride he makes fun of my vintage bikes with Stronglight, Nervar, SunTour and Campagnolo cranks...

(yeah, I know about the issue with some Campys)

Kontact 

Abandoning a working standard would be easier in the long run? I don't think so.

Kontact 

Why didn't he warranty his crank? I've been sending these in for warranty replacement for years.

tiger1964 

No idea... I'll ask. I suspect bike is out of warranty, and I think he had the service done at a shop other than the original bike purchase.

Bike Gremlin

It worked fine with the quill stems (replaced by threadless stems & forks).

Bad (and, I would argue, unsafe) patents should be replaced. The tech. exists. It has existed for decades.

Relja