Shimano Crankset recall: bonded Hollowtech ones

[Mo1959]

Hmmm, think my 2018 Specialized Ruby might have this crankset. For all the times I am actually riding these days, I might just hope it's ok.

 

[13 rider]

Hmmm, think my 2018 Specialized Ruby might have this crankset. For all the times I am actually riding these days, I might just hope it's ok.

The bike shops are really just doing a visual inspection looking for any cracks which to be honest you can do yourself . Any clicking or creaking from the chain set is the first sign of failure so just keep an ear out for that . The source of the problem apppears to be galvanic corrosion caused by a chemical reaction between the different metals and salt and water so if you've ridden in the dry mainly it unlikely you will get an issue

 

[fossyant]

The quest for ever lighter kit eh. The biggest issue (for me) is the proprietry chain rings that are needed. Three of my bikes use standard 5 arm 130 or 110 BCD patern, you can get any chain rings. Two don't - one uses a slightly unsual BCD but I can get aftermarket rings, and the other set is SRAM and it's only their rings I can get, at cost (I do ebay searches to pick up spares before I need new rings).

 

[Cycleops]

The quest for ever lighter kit eh. The biggest issue (for me) is the proprietry chain rings that are needed. Three of my bikes use standard 5 arm 130 or 110 BCD patern, you can get any chain rings. Two don't - one uses a slightly unsual BCD but I can get aftermarket rings, and the other set is SRAM and it's only their rings I can get, at cost (I do ebay searches to pick up spares before I need new rings).

That's the price you pay for progress.

 

[fossyant]

That's the price you pay for progress.

My old 7400 series cranks are lovely, as are the Shimano 600. Only issue is they are 130mm BCD, so no namby pamby compact gears !

 

[Domus]

Removed my crank and cleaned both parts. Inspected under a bright light and can see no problem at all, bonded joints all seem very tight. Chainrings re fitted and ready to refit to bike with new BB bearings as they seem quite gritty.

 

[13 rider]

I spoke to my bike shop yesterday to check if there's a time limit to when you need to get them checked or registered, they said no so I'm leaving it until the bike needs to go in for something else . In the meantime I've done my own visual inspection and will keep listening to any strange creaks/ ticks from that area

 

[Cycleops]

Class action lawsuit launched in the US:

https://road.cc/content/news/lawsuit-filed-against-shimano-cranksets-usa-304439

 

[DCLane]

My first four bikes (NeilPryde Nazaré, NeilPryde Bayamo, son no. 2's Ridley Noah and the Viner Mitus) all checked and are OK for now. The other four are in for checks along with spare cranksets we have.

 

[silva]

Just some thoughts...

https://road.cc/content/tech-news/shimano-claims-no-design-problem-hollowtech-cranks-287827

Shimano denies design problem with Hollowtech cranks despite reports of cracked arms

Thousands of cases, yet denial of a design problem.
But what are alternative explanations? Too many people with too much leg power due to a mutation in their bio?
All those people where hit by a car on that crank?
In science they say that the observation overrules the theory.
It's clear that Shimano just attempted to manoevre out the reputation and with it, sales blast.
That long. Until the attempt itself already did that, and further denial would just make it worser.

Why did Shimano started to make cranks hollow?
To save on weight, is a given explanation.
But the cranks of a bike, are a small fraction of the weight of a bike.
So unless for racing people, competition, the gain is not worth the hassle/the specific vulnerabilities of aluminium.
I think that the real reason is just cutting cost. Alu is much easier>cheaper to machine than steel.
In such a degree that, instead of just massive material, even "constructing" a crank from parts, still cuts the cost more, with the weight saving argument used as excuse-explanation.
A crank is a bike part that undergoes alot leveraged force (strength) and alot force fluctuations (stress>fatigue), causing the mounting positions to be critical.
Look at the picture of the broken spider crank, it's clear that the first break was the one near the pedal eye "insert" of whatever that is named, the 2 crank U shaped parts separated, thereby wiping out the strength that construction adds, usually meaning a total erasing of strength in at least 1 direction, the outwards U then broke off near the spider, and garbage the entire crankset and with bad luck, and with this part of a bike, it doesn't have to be *that* bad luck, garbage is your head too.
Add to that design a vulnerability to a variety of kinds of corrosion, and you have a recipe for sudden disaster, and that's what was "observed", that Shimano kept denying probably until their lawyers told them that an admit and recall would end cheaper.
This is an advertisement extract:

Hollow forged crank arms A lightweight crankset not only reduces the bike's weight, but decreases rotating mass to aid in acceleration. The challenge is to reduce the weight of the crank without reducing its strength and rigidity. SHIMANO's advanced forging technology has solved the problem through the HOLLOWTECH crank.

That bike's weight reducement, as said above, I consider that futile.
That decreasing rotating mass in acceleration is blah, the mass of a crank is spreaded over its length, and at the outer end there is a pedal, about 200-400 gr, what's a hollowtech crank? <100 grammes? And a shoe, and a foot, ... ? Then tell me how inertia would make any difference worth the hassle?

Not that Shimano deserves a special blame here, alot stuff these days is made like that for that same reason of cost cutting. Selling crap with a quality + quality control mark and spare parts included is default practice.
The product ends in a garbage bin without any spare part used because the typical wear parts last longer than the body. :P

 

[fossyant]

Hence why I don't have any hollow cranks. You don't see that on Shimano MTB cranks. I'm not keen on carbon cranks either.

 

[Jameshow]

Just some thoughts...

https://road.cc/content/tech-news/shimano-claims-no-design-problem-hollowtech-cranks-287827

Thousands of cases, yet denial of a design problem.
But what are alternative explanations? Too many people with too much leg power due to a mutation in their bio?
All those people where hit by a car on that crank?
In science they say that the observation overrules the theory.
It's clear that Shimano just attempted to manoevre out the reputation and with it, sales blast.
That long. Until the attempt itself already did that, and further denial would just make it worser.

Why did Shimano started to make cranks hollow?
To save on weight, is a given explanation.
But the cranks of a bike, are a small fraction of the weight of a bike.
So unless for racing people, competition, the gain is not worth the hassle/the specific vulnerabilities of aluminium.
I think that the real reason is just cutting cost. Alu is much easier>cheaper to machine than steel.
In such a degree that, instead of just massive material, even "constructing" a crank from parts, still cuts the cost more, with the weight saving argument used as excuse-explanation.
A crank is a bike part that undergoes alot leveraged force (strength) and alot force fluctuations (stress>fatigue), causing the mounting positions to be critical.
Look at the picture of the broken spider crank, it's clear that the first break was the one near the pedal eye "insert" of whatever that is named, the 2 crank U shaped parts separated, thereby wiping out the strength that construction adds, usually meaning a total erasing of strength in at least 1 direction, the outwards U then broke off near the spider, and garbage the entire crankset and with bad luck, and with this part of a bike, it doesn't have to be *that* bad luck, garbage is your head too.
Add to that design a vulnerability to a variety of kinds of corrosion, and you have a recipe for sudden disaster, and that's what was "observed", that Shimano kept denying probably until their lawyers told them that an admit and recall would end cheaper.
This is an advertisement extract:

That bike's weight reducement, as said above, I consider that futile.
That decreasing rotating mass in acceleration is blah, the mass of a crank is spreaded over its length, and at the outer end there is a pedal, about 200-400 gr, what's a hollowtech crank? <100 grammes? And a shoe, and a foot, ... ? Then tell me how inertia would make any difference worth the hassle?

Not that Shimano deserves a special blame here, alot stuff these days is made like that for that same reason of cost cutting. Selling crap with a quality + quality control mark and spare parts included is default practice.
The product ends in a garbage bin without any spare part used because the typical wear parts last longer than the body. :P

Because we all want to feel like we are racers, or at least those who buy carbon bikes from new who are susceptible to advertising, marketing, peer pressure!

 

[wafter]

Just some thoughts...

https://road.cc/content/tech-news/shimano-claims-no-design-problem-hollowtech-cranks-287827

Thousands of cases, yet denial of a design problem.
But what are alternative explanations? Too many people with too much leg power due to a mutation in their bio?
All those people where hit by a car on that crank?
In science they say that the observation overrules the theory.
It's clear that Shimano just attempted to manoevre out the reputation and with it, sales blast.
That long. Until the attempt itself already did that, and further denial would just make it worser.

Why did Shimano started to make cranks hollow?
To save on weight, is a given explanation.
But the cranks of a bike, are a small fraction of the weight of a bike.
So unless for racing people, competition, the gain is not worth the hassle/the specific vulnerabilities of aluminium.
I think that the real reason is just cutting cost. Alu is much easier>cheaper to machine than steel.
In such a degree that, instead of just massive material, even "constructing" a crank from parts, still cuts the cost more, with the weight saving argument used as excuse-explanation.
A crank is a bike part that undergoes alot leveraged force (strength) and alot force fluctuations (stress>fatigue), causing the mounting positions to be critical.
Look at the picture of the broken spider crank, it's clear that the first break was the one near the pedal eye "insert" of whatever that is named, the 2 crank U shaped parts separated, thereby wiping out the strength that construction adds, usually meaning a total erasing of strength in at least 1 direction, the outwards U then broke off near the spider, and garbage the entire crankset and with bad luck, and with this part of a bike, it doesn't have to be *that* bad luck, garbage is your head too.
Add to that design a vulnerability to a variety of kinds of corrosion, and you have a recipe for sudden disaster, and that's what was "observed", that Shimano kept denying probably until their lawyers told them that an admit and recall would end cheaper.
This is an advertisement extract:

That bike's weight reducement, as said above, I consider that futile.
That decreasing rotating mass in acceleration is blah, the mass of a crank is spreaded over its length, and at the outer end there is a pedal, about 200-400 gr, what's a hollowtech crank? <100 grammes? And a shoe, and a foot, ... ? Then tell me how inertia would make any difference worth the hassle?

Not that Shimano deserves a special blame here, alot stuff these days is made like that for that same reason of cost cutting. Selling crap with a quality + quality control mark and spare parts included is default practice.
The product ends in a garbage bin without any spare part used because the typical wear parts last longer than the body. :P

I think their actions are driven by a combination of both lightweight and cost - let's not forget that typically in recent years 105 has been functionally very, very close to Dura-Ace; the big difference being the latter's reduced mass to justify the fact it costs what, 2.5-3 times as much...?

For years the bike industry has made a false idol out of light weight; sales and marketing are so much easier when you've told the customer what they want before selling it to them. Far easier to push an arbitrary feature as desirable over all else and feed the artificially-created demand for said feature, rather than try to make your products actually fit the genuine needs of free-thinking people.

Same happened with digital cameras in recent times - everyone who didn't know any better bought based on image resolution (megapixels), assuming, based on marketing crap that more was better - yet the reality was often quite the opposite.

In principal the hollowtech format makes sense - for a given stiffness you can make a large box-section lighter than a small solid section. While I'm skeptical of aluminium in some applications (frames, mostly) it's been used for many bike parts (cranks included) for many years, and while I'm more comfortable with steel, it seems that if designed for correctly ally is perfectly acceptable.

I remain intrigued to know exactly how the construction process of the apparently not-failure-prone 105 R7000 crankset differs from the otherwise visually / geometrically identical snap-happy Ultegra and Dura Ace alternatives.. some say they're "welded" but I can't see how this would be cheaper than just slapping some adhesive between two bits, as is the case with the two more expensive alternatives. Maybe the difference is entirely mass-driven and the 105 needs thicker walls to accommodate the different joining process..?

Hence why I don't have any hollow cranks. You don't see that on Shimano MTB cranks. I'm not keen on carbon cranks either.

Certainly share that perspective with placcy cranks; while I don't much like the fat aesthetic of the box-section road cranks either (nor the snappy-snappy of course!).

Do we know what construction is used for GRX cranks? It's hard to tell from the pics although I'd guess they're maybe forged / single-piece like the MTB cranks..

 

[C R]

Thousands of cases, yet denial of a design problem.

It is possible for there to be no problem with the design and still get large numbers of failures. It could be that the assembly procedure is no sufficiently well specified and/or controlled. It could be that the glue specification is not suitable for some use situations, or that the wrong glue was being used. It could be that a certain finish was specified for the contact surfaces but the parts supplied didn't achieve it, and so on. We just don't know enough and Shimano will most likely obfuscate in order to hide what really happened.

 

[Ajax Bay]

This is a Bike Radar article from 2020 (2020!):
https://www.bikeradar.com/features/shimano-crank-failure/
These failures are starting from the spider not from the end.

So unless for racing people, competition, the gain is not worth the hassle/the specific vulnerabilities of aluminium.

Cranks have been made of aluminium (not steel) for many years (spindle is steel) it's an ideal material for cranks. The displayed failures are caused by glueing challenged by galvanic corrosion resulting from steel (spindle) and aluminium box section crank/spider.
A 2020 Cycle Chat thread: https://www.cyclechat.net/threads/strange-crank-failure.259268/page-2
Hambini (a year ago):
View: https://youtu.be/-uK7FSZ6OFM