Hey all, I have to give a presentation in a few weeks for a Fracture Mechanics class and I get to pick the topic so long as it pertains to the failure of a material. This could range from disastrous failures (comet jets, liberty ships, challenger explosion, etc.) or intentional failures (shear pins, explosive bolts, etc.). But, I want to do one on a failure in cycling. I remember Cav’s wheel buckling during a sprint a few years back and I seem to remember a track cyclist who sheared his stem somehow. I’m looking to the great wisdom of ST to provide some ideas… Do you have a favorite crash that was caused by a material failure?
Lots of video and discussion of Hincapie’s steerer failure in Paris Roubaix. This is an example where the failure caused the crash.
There’s also the world record speed attempt down down the side of a volcano when the frame’s head tube failed: https://www.youtube.com/watch?v=rTfu0hjVtzE
I don’t think Cav’s wheel folding was the cause of the crash you mentioned but it does make for striking video/images.
Off the top of my head, crank arm failures are pretty common in bike racing, especially during sprints or climbs
.
Off the top of my head, crank arm failures are pretty common in bike racing, especially during sprints or climbs
“Pretty common”?
Not really, but OK.
Hincapie’s steerer tube failing is a great example of material failure causing a crash. As noted, Cav’s wheel folded as a result of the crash…it was not the cause of the crash.
You may wanna check into Spinergy wheel failures as well…they had a nasty tendency to implode.
Off the top of my head, crank arm failures are pretty common in bike racing, especially during sprints or climbs
“Pretty common”?
Not really, but OK.
Hincapie’s steerer tube failing is a great example of damaged material failure causing a crash. As noted, Cav’s wheel folded as a result of the crash…it was not the cause of the crash.
You may wanna check into Spinergy wheel failures as well…they had a nasty tendency to implode.
Modified, slightly…
Off the top of my head, crank arm failures are pretty common in bike racing, especially during sprints or climbs
“Pretty common”?
Not really, but OK.
Hincapie’s steerer tube failing is a great example of damaged material failure causing a crash. As noted, Cav’s wheel folded as a result of the crash…it was not the cause of the crash.
You may wanna check into Spinergy wheel failures as well…they had a nasty tendency to implode.
Modified, slightly…
Fair enough…I’m not certain I ever really bought their explanation, but without any evidence otherwise…
Video of the crash.
https://www.youtube.com/watch?v=UZg1vrvGbdE
Also look at Lambert bikes from the 70s that had an aluminium fork that was prone to failure - aka death fork.
http://sheldonbrown.com/lambert.html
Off the top of my head, crank arm failures are pretty common in bike racing, especially during sprints or climbs
“Pretty common”?
Not really, but OK.
Hincapie’s steerer tube failing is a great example of damaged material failure causing a crash. As noted, Cav’s wheel folded as a result of the crash…it was not the cause of the crash.
You may wanna check into Spinergy wheel failures as well…they had a nasty tendency to implode.
Modified, slightly…
^^^This. As mentioned Hicapie’s and Cav’s crashes are due to damaged components (so don’t really count IMO).
Spinergy is a great example of a fatigue-induced failure (ironically at a reinforcing rivet) causing a cascading failure (losing one spoke overloads the remaining spokes as they pass through the load cycle causing the wheel to “explode”). It’s a classic bad design (a-la Liberty ships).
Do you have a favorite crash that was caused by a material failure?
http://inrng.com/2012/08/1982-fignon/
And I didn’t crash, but personal “favorite” was the bolt holding my saddle to my seatpost breaking at about mile 90 of a 100-mile stage of the old Killington Stage Race. I rode finished, out of the saddle the whole way (except for a few minutes sitting on the top tube). Up the last climb people would see me coming looking terrible, and get a sort of “pity him” look on their face. And then as I rode by and they saw I had no saddle they’d just gasp.
Graeme Obree’s Bottum bracket separation on his hour record attempt…
This is likely weld penetration . HAZ causation however rather than cyclic stress failure… but if your no differantiating…
I remember in the mid-1990’s, there were a lot of all carbon forks breaking in the Pro peletons. They were the early models with carbon steerer tubes and manufacturers were trying to keep the weight down.
I remember in the mid-1990’s, there were a lot of all carbon forks breaking in the Pro peletons. They were the early models with carbon steerer tubes and manufacturers were trying to keep the weight down.
Were they breaking and causing crashes or breaking in crashes? Big difference between the two.
I certainly remember a lot of talk of carbon stuff breaking, but most of it was hearsay. Spinergies exploding, frame cracking while “just riding along,” bike frames coming home in little boxes. Lot of FUD it seemed to me. Or, at least, steel and aluminum and ti stuff broke too.I had a titanium frame separate at a weld for example. And if anything, I think the CNC-machined stuff of the 90s was the worst.
That said, a teammate of mine broke a carbon steerer tube on a relatively new bike about three years ago,
I remember in the mid-1990’s, there were a lot of all carbon forks breaking in the Pro peletons. They were the early models with carbon steerer tubes and manufacturers were trying to keep the weight down.
Define “a lot”…
And carbon steelers didn’t start to show up until the late 90’s…there may have been a Taiwanese company doing carbon earlier, but none of the big boys (Kestrel, Look, Time, Reynolds) were. There wasn’t widespread acceptance of them until the 2000’s.
Google “Mavic R-Sys” for other stories/pics of spontaneous breakage.
What about the track rider with the front disc wheel the just starts shredding layers one by one? That wasn’t caused by a crash.
Thanks for all the replies! I should clarify that it doesn’t have to be a specific type of failure (fatigue, shear, SCC, buckling, etc.) nor does it have to be a failure of a mechanically sound material, that is, the material can already be damaged but still in use - like in Hincapie’s crash. He was likely riding on a damaged steer tube caused by a previous crash, there was probably a crack that propagated due to the cobbles and reached it’s critical size.
There are a lot of good options here though, I have a lot of time so I’ll take all suggestions.
I always think of plain old stainless steel spokes. Everyone who’s ridden much has experienced it. They say well built wheels will never brake a spoke, the rim or hub will wear out first. They also say so many other things you could easily fill up a paper/presentation of any length.
Hincapie had crashed earlier in the race. iirc, his bars were twisted, but I don’t remember for sure - in addition to fat and slow, I’m old, too.
What I do remember is the number of people claimed this was a good reason not to use forks with carbon steerers, even though this is clearly not a carbon steerer.
Most bike failures are kind of boring. Do a search for Kimi Raikonnen flat spotting a tire in F1 which eventually led to suspension failure from vibration.