Koyote

I know a guy who did that. The cranks were White Industries.

am8117

Or maybe they will move back to the 5-arm design because overall weight savings when spread over 5 bolt areas would allow them to ditch that hideous plastic cover too.

I have not been paying attention that much but these news have been around since a while now, even in the less controversial online sources, so the Hambinis and Ozcycles were just ahead of the time:

https://road.cc/content/tech-news/sh...-cranks-287827

Also, thanks for your reply as a whole, it was nicely put together. For some reason I had always thought the "hollow" refers to the 2-piece crankset design where the spindle got hollow, not to do with crankarms.

Andrew R Stewart 

since Al cranks became the norm there have been many stories of broken arms. Campy NR has had some fractures through the arm at the end of the lightening groove that was milled in their face. The base of RH arm and spider web stress crack is very well known. pedal eyes are another location of fractures. Even some tapered axle hole cracks happen.

My experience is that the high volume low cost cranks are less likely to see these failures for a few reasons. More material that has less machining, thus fewer stress risers and more meat. Maybe the fewer miles many lower cost bikes see helps keep the number of units that have seen a lot of stress cycles down WRT the number made.

Now the higher cost stuff we covert sees far more issues IME. They have had more material removal for weight or style. They see, on average, what's likely greater peak loads and any load for more miles. And any failure likely has more "emotion" after. Spend the big bucks for parts that are meant to work better and be lighter, and when they don't get on your soapbox. Note I didn't say work longer... Andy

I should also note the number of bonded carbon cranks that have had their pedal eye inserts break loose, another campy issue.

am8117

But the pictures only show the aftermath, not sure what the actual event of that happening looks like but one could imagine if it's with high cadence and abrupt that the remainder of the damaged crankarm to cut open one's calf causing a crash too.

Andrew R Stewart 

Not sure your point here. I will say that cycling can be a dangerous activity. Working the LBS one gets to hear so many stories of falls and crashes.

I will suggest that some component caused crashes are from the component not being monitored frequently enough. Andy

am8117

I was particularly getting at that either in the video or one of those articles linked there was a distinction made between components that manufacturers consider critical for safety (as in failure is likely to cause injury or worse) and others that are not necessarily considered equal. There are the "lips" on the forks despite everyone should know how to mount their front wheel properly, not to mention it should feel funny before going, but ...

This thing apparently was not designed with that margin of safety in mind.

I do not know how quickly it goes from the visible cracks appearing to catastrophic failure, so won't speculate on the inspections, but surely most people don't do ultrasounds on their crankarms like the aerospace industry would be expected to - just to catch up with that comparison above by someone else.

My point overall is that Ultegra and above might be designed to be good for one race only whereas lots of people use some of it on their "regular" bikes putting long miles instead, but of course I am NOT telling anyone what to buy to stay safer eg 105. Just they might consider that.

CliffordK

I've commuted on a road bike all of my life. The old Colnago is over 50 years old. I'd hate the thought of buying a really expensive crankset every couple of years (potentially costing more than I paid for the entire bike).

For those racers, they may have some "race day" equipment, but they also spend a lot of time on the road training. Some may have a trainer bike and a race bike. Others just have one bike. Others may wish to have the same equipment on training and racing bikes, or use hand-me-down equipment for training.

No doubt Shimano monitors complaints of severe injuries and death caused by equipment failure.

I have no idea what it feels like to have a crank break. It is part of one's stability on the bike, and potentially could throw a person off balance. There are times that one anticipates constant power to get away from traffic, and if one stops dead in the middle of the road, it could be inconvenient. And, of course, the annoyance of being in the middle of a ride with a critical failure.

I'm not surprised Shimano doesn't want to do a recall. The solution would likely be complete replacement (once they figure out how to fix the problem).

But, the right thing to do would be to extend the warranty to replace broken equipment due to a design problem and manufacturing problem. That would at least keep customers happier.

Say 1 in 1000 breaks, or even 1 in 100 (1%). Replacing them would be expensive, but really wouldn't impact the company's bottom line that much.

Polaris OBark

That's the main point. The spindle is steel and the rest is alumin(i)um.

High School oxidation/reduction reaction potentials.

He points out that the potential difference if you have carbon and aluminum is much larger.

Darth Lefty 

The deal here is that crank arms of any style of any brand of any material really should be designed to last indefinitely under a full sized American customer. You can expect trouble at moving parts and fasteners... the bearings, the bolts, the pedal eyes... but the arms should fail JRA about as often as frames and forks, which should be never except in freak circumstances or insane high mileage. This is a design escape, which is something that happens. The real sin is the total lack of follow up. Yeah of course they don't want to! No one wants to. They have to. That's basic ethics.

Shimano may still be the biggest gorilla and even still growing but the fact is that a lot of other companies have managed to develop a decent percentage of market share due to crap like this

Russ Roth

What's the issue with the pedal mounting interface that I've missed all these years? Although I've seen failures from poorly installed parts, I'd have to say that pedal threads are one of the very few items I've never had fail on a bike, and I've broken pretty much every part on a bike at one point or another.

Bike Gremlin

Causes fretting damage which leads to cranks cracking near the pedal interface.

Some more words and pics:
Unsafe and bad cycling industry patents - Pedal to crank interface

shelbyfv

They might be but obviously they aren't. Ultegra specifically is the enthusiast's workhorse. It's silly to pretend that lower level components are somehow safer and that there is any reason to use them other than budget.

CliffordK

If you read above, and watch the videos above, 105 is fundamentally different than Ultegra (Hollow Forged vs Hollow Bonded). And thus so far seems to have lower failure rates.

Of course it is possible that people have been pounding the Ultegra/Dura Ace with higher miles. But, the 105 doesn't have that vulnerable glued seam.

The 105 does still have the steel/aluminum spindle interface which may impact longevity in some environments, but doesn't seem to be as big of an issue as the glued seams and thinner metal.

Polaris OBark

In the video, and on the accompanying web page, he suggests that 105 will be less likely to fail due to galvanic corrosion, because the steel spindle is welded directly to the aluminum crank-arm. He says that galvanic corrosion will still be possible (since the weld conducts), but it won't be likely to fail in the same manner. I am unclear why that would be the case, but he is suggesting this, presumably for a valid reason, so it isn't quite at the level of being "silly to pretend." It would be interesting to see if the failure rate is significantly lower (or higher).

sweeks

Reading all this makes me happy that I have 20-year-old Ultegra cranks. They're hollow forged, and I think they look better as well.

Ultegra with a more traditional appearance.

shelbyfv

My comment was directed toward the poster I quoted who seems to have the notion that Ultegra is a "race day" group. Even on the internet I've never heard of anyone swapping out an Ultegra or DA crank for a 105 because they were concerned about safety.

Polaris OBark

But it might be a valid reason to consider a 105 or the lower-priced GRX crankset as a valid option when replacement time comes along. (Since your comment wasn't a pm, I just assumed we were all having a conversation, it being a forum and all. Sorry. Sorry also I didn't notice the poster just prior to me said essentially the same thing, fwiw.)

shelbyfv

Anything is possible. I'll post If I ever hear of anyone doing that.

CliffordK

One of the clips I posted above had a person who broke one Dura Ace crank, and one Ultegra crank. The third replacement crank is now a 105... hoping it will last longer.

Not breaking cranks certainly would seem to be worth considering, especially if one is building up a bike from components.

sweeks

I was riding my Dahon Mu XL folder to work a few years ago when I noticed that the left pedal seemed to be rotating around a different axis than usual. When I got to work, I observed a crack almost all the way through the middle of the crank. I reinforced the crank with dental acrylic (available in plenty at my job at a dental school!), and it survived the 3-mile return trip home with *light* pedalling. I replaced the (no-name) arm with one from a local shop's spares bin, and the bike survives.

Amen!

am8117

Just wanted to clear up that it's now with hindsight that it starts to appear that way. It is not what the customer has been expecting or the engineering intended, but now that Shimano does not seem to be following up on that they are somewhat normalising that it may fail that way. At the same time, it has not failed famously in any of the races, so it is obviously a fatigue and/or corrosion related.

And by treating it the way Shimano does, not publishing eg reported figures stats and steps planned to be taken in order to address this they are going down the 737 MAX route only this time no one has been reported having been involved in freak accident yet or to draw the parallel more close on racer had their crank fail that way on live TV while pushing it downslope and ... caused a horrible PR event.

I do not appreciate the part - if I got that right - insinuating that we buy what the budget allows and if budget allows Ultegra we don't do eg Sora. It's not that simple especially when one's safety or reliability is in question.

I for instance take long routes where they might be no bike shop at hand and do not want to have to walk the bike because it has had it's crank split open. I might be the crazy one who rides 32 spoke cross-laced wheels for the same etc but weight is not everything and looking fancy neither. I am not a racer but if I was I would not mind my training bike be "inferior" because what does it matter when riding for fun or keeping fit?

Polaris OBark

I bought the lower-priced GRX crankset (akin to 105) because the small ring had 30 teeth instead of 31. If it were reversed, I would have paid more for the 30 T. (I paid a LOT more for my White Industries crankset, and I think the $150 GRX is better.) I do confess I felt a little bit like I was slumming it, since the rest of the drivetrain is Di2 ultegra on an expensive hand-made custom bike. But if the cheaper crankset is more corrosion-resistant, I do feel a tiny bit more justified.

sincos

The issue isn't that things break, or that a design has a flaw that makes itself known in the real world. That happens. What's disappointing is when a company allows a known design flaw to persist over several generations. There's a well known photo of Fignon sitting on the road when his Campy titanium spindle snapped. Campagnolo realized that they'd been too aggressive with the weight shaving and beefed it up in later units. Similarly. there was a spate of NR cranks cracking at a stress riser, and some 60's Stronglight cranks didn't have enough material around the pedal eyes and cracked there. But those were fixed also. It's doubly disappointing because Shimano does have a solution (it's called 105), but market segmenters in the company won't allow it to be used on "higher-end" lines (and of course we consumers suck them up). Come on Shimano, you're better than that.

CliffordK

Hmmm... I remember when Dell had blown capacitors across several generations of motherboards. And, I guess the issue hit industry wide. It takes some extraordinary leadership to ignore a problem that one has already discovered exists.

Shimano is working themselves into a bit of a corner, with 105 cranksets about 100 grams heavier than Dura Ace. And, they're still struggling to compete with SRAM and Campagnolo on weights. Their glued crankset is an extraordinary design, but likely sees multiple stresses causing failure.

Racing Dan

I could find no mentioning of a failed 105 crank anywhere. Failed Ultegra and DA are plenty. Its worth noting that this issue is not, to my knowledge, affecting the also bonded XTR mtb cranks.