Ironically, the Marginal Gains Podcast out this morning, but recorded a few days before this crash is a topical episode about Bifurcation and covers speed wobble, Tacoma Narrows Bridge collapse and aeroelastic flutter (and a little bit about COVID modeling..)

https://podcasts.apple.com/...4247?i=1000492704533

We've known Chloe since she was a kid, her uncle worked with me at Zipp for years and she is truly one of the toughest people I've even known. If it isn't fatal, she'll be back..

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http://www.SILCA.cc
Check out my podcast, inside stories from more than 20 years of product and tech innovation from inside the Pro Peloton and Pro Triathlon worlds!
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Actually, you lead by turning your bars in the opposite direction...

Precisely. Countersteering is required on a bike or a motorcycle at speed. She could have countersteered and leaned over, possibly making the turn, or possibly low siding, which, at that speed might have have resulted in even worse injuries as she contacted the guardrail causing a very sudden stop.

But the initial loss of control and continuation of the speed wobble looks to be an overly stressed front wheel, that isn't able to sustain without severe flexing and resonating, instead of dampening, the lateral forces generated by the little slip, either on a pebble, or possibly some other anomaly in the pavement at that point where the wobble began.

I know Zipp is a major supporter of her, but they should be looking in to the stability of their wheels in less than optimal conditions, such as this, ie: when, for whatever reason, the forks are not in alignment with the direction of travel, and the wheel and tire are hopping, instead of rolling.

We all want the most aero, and the lightest equipment possible, but sometimes the engineering will then fail us in the sub-optimal condition, like this, or when the wind blows at a certain speed in the Tacoma Narrows.

On another point, those barriers are not designed for bicycle safety, at all; they were designed to keep cars from going over the edge. It looks as though her leg was sliced when she contacted the top of the vertical support post on the backside of the rail. From now on, on every bike course, at least, if not everywhere, the tops of those rails should be covered with either a permanent or temporary insulation to prevent the ripping of flesh. Even a retrofit would be easy to design.

With that in place, the next Chloe could get up and finish her race at least, if not win it.

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Also she rolled the dice and took the hairpin turn in the aero position. Which meant that her counter steer needed to come from pushing down really hard with the right aero pad with her right elbow. I used to get athletes to practice this by taking a turn on a quite street in the aero with all rear weight on the left leg and all upper body weight on the right aero pad and actually get to the point where you remove left arm entirely from aeropad (you can take the turn with your left hand behind your back as a handling test or weight distribution). So left leg/hip rear wheel steer and right elbow aero position counter steer. But once she got into the speed wobble, given she was stuck in aero, clenching top tube with both knees becomes problematic, and also counter steering with right elbow become problematic.

I don't think you can blame the location of the protective pads or the type of guardrail. These are hazards of any race on normal roads and the type of injury is just pure bad luck. There is always something theoretically really bad out there that is not that bad until a catastrophe reveals how bad it is.

Just want to say that Chloe is an excellent bike handler. She lapped the W Elite field at Snake Alley Crit as an 18 year old. Very technical race that is all about the scary downhill.

Looks like she got it wrong here, pushed the envelope too far. But only a few pros have as good a handling ability and confidence.

That's an awfully convoluted way of saying something simple.
Are you trying to say: "Mistakes can cause crashes and are more likely if you're less skilled or more fatigued."?

Or unfortunately Chloe may just have sneezed?

I'm amazed that any 2yo manages to corner their balance bike!

Also, the best bike handlers/descenders are the ones who are just one corner away from being found out; see Marc Hirschi.

Well said. I kept thinking that this year - Hirshi crashed once and came very close in a few other instances. The announcers kept raving about what a great descender he is, however it looked to me like he made lots of mistakes but just had the nerve to keep pushing it. I don't think he's a bad descender at all - but wasn't exactly a clinic in bike handling either.

Same with LFF last year - much was made of his descending, but in the main instance where he put time on folks on the descent, it was when he was the only one in the group with disc brakes. He is a very good bike rider and handler, but there are a number of guys who are his equal when it comes to pointing a bike downhill and keeping the tires down.

The "best descender" usually is riding a razors edge from just being out of control. I don't think it necessarily translates to best bike handler.

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"It's good enough for who it's for" - Grandpa Wayne

Well the best descenders like Paolo Salvodelli (Il Falco) who won the Giro because of his descending off Finestre, are the guys who ride on that razor's edge on the right side of control and succeed in staying upright. It is the same thing with downhill skiers. That's what being a great descender is all about - not crashing when everyone else who would carrying that speed would lose control and crash and not be able to handle their bike. I would say by definition a good descender has great bike handing skills or they will be dead. A person who descends slow and safe won't be included in the category of great descender because they don't crash. The great descender club (whether a bike racer or skier) are those who stay upright at the fastest imaginable speeds relative to peers.

Great descenders can also have bad luck at speed, but that's like an investor who puts some of the portfolio in high risk stock. The reward is great, but the downside sucks too. Chloe may have gambled (in the sense she chose her speed and chose to stay aero) and kind of lost on this one, but most of the time, she's on the right side the gamble

You don’t have quite the same control on a tt bike but much like the Tiesj Benoot crash at the tour.


Was thinking the same thing - very similar to the Benoot incident in the Tour - except Bennot was going left and Dygert was going right, and the BIG one, Benoot walked away from his crash and was back on the bike and riding in 20 - 30 seconds. Dygert has from what I understand a completely lacerated quadriceps muscle, she will be out of action for a long time, and who knows if she can fully recover from something like that??

As others said - had that padding extended around the curve fully, she would have still gone down, but she most likely would have been able to get back on her second bike finished and possibly won the race!

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Steve Fleck @stevefleck | Blog

I would disagree with this. I had a front tubeless tire burp and flat at speed in a corner. I went down hard and the front slid out and the tire stayed on the rim and actually protected it. Tubulars often do the same thing too unless you roll them. Regardless of what happened, it was horriffic.

While watching one of the replays, I noticed the padding extended way above the guard rail

I'm wondering that maybe they should've put them ==== instead of [][][][] and they would've had enough to take care of the whole turn???

"Why do the pads stop here?"
"You only gave me these many and I ran out of 'em"

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

I posted on FB about this.

Not sure the UCI regs on dimensions for the lady's TT bikes, but her reach looks further judging the forearm to upper arm angle when comparing to a person like Ganna, Dennis, or Campanaerts.

Anytime in the past I ran that much reach, the bike was harder to handle. Not sure if video or bike but it looks like that bike is swaying a bit (including the front end) while just riding flat out earlier. I say that looking at other riders not swaying. I wound up setting my TT bike up to UCI regs despite not needing too as a slow USAC rider for this reason, stability.

Any little slip, rock, or otherwise in the aerobars in a corner with the lower stability amount of reach could be bad.

Just my uneducated conspiracy theory for this one.

UCI regs for TT bikes are the same for female and male.

Sad what happened, but she was just too fast. I think she was the only one trying to take this right turn in aero position. All other female and male I saw on tv took it on the base bar.

If you're already turning you are on the edge of the tire and not the radius, the tire will be pushed to the outside (higher side) if it blows, then the rim hits the ground. Doesn't matter what type of tire.

The only time I've seen tires get ripped off is when it is slid on its radius.

However, we know this didn't happen in her case.

Agreed it was horrific.

Agreed.

As a rule of thumb, if I can't pedal through it while making my intended target power......I probably should be on the base bar.

Ya, not saying your logic doesn't make sense...it's just not what happened to me. I had a new set of carbon rims, had a tire burp in corner going quite fast, lost all air, went about 30 yards, and the rim didn't have a mark on it...I, however, did.

Yeah, I also saw her saddle oscillating when I watched in slo-mo. It seems almost impossible for the saddle to oscillate like that unless she wasn't sitting on it (in part because her hips were not oscillating with the saddle). It makes me wonder if unweighting the saddle is what changed the harmonics and initiated the wobble. At full speed, there seems to be a bump before all the craziness -- maybe that threw her off the seat. Of course, maybe the wobble is unrelated to her not sitting and the unweighting was an effect and not a cause of the wobble.

Dev -- I have had no training on bike handling, so could you explain the above? It seems to me that the counter steer comes from counter steering (i.e., turning the front wheel in the opposite direction of the turn). Why is pushing vertically down on the arm pad a more effective way to turn the front wheel than merely applying a little horizontal force with your hands at the end of the aerobar?

Also, maybe you can help with the concepts of turn with the hips and the turn is with the rear wheel. My understanding of the physics is that if center of gravity of the bike/rider is to the right of the wheels, the bike will turn right (does it turn to the right because the rider turns the front wheel to the right once the appropriate lean is achieved?) and visa versa. The counter steer is to achieve and maintain the desired off center and resulting turn radius. Putting weight on the outside pedal is to get the upper body to lean into the turn farther than the bike is leaning so that you can keep the bike more upright for a given degree of off center, thus keeping more of the working portion of the tire on the tarmac -- especially important if the off center needs to be more extreme (pointing your inside knee into the turn also helps with this). The acceleration in the turn direction has to come from both wheels (otherwise, the rear wheel would track around the turn, but the front wheel wouldn't).

So do I not understand the physics? Are the concepts not intended to explain the physics, but merely cues that help riders harness the physics? Help!

She's out of the hospital and heading home.
https://usacycling.org/article/dygert-released-from-hospital-after-road-worlds-crash

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Shawn
TORRE Consulting Services, LLC
http://www.TORREcs.com

I’m not sure the full extent of her damage but I have the image of Phinney’s life less body planted into the wooden guardrail supports burned into my head. I came flying through moments after the Com car stopped. I got dropped on the climb after pulling on the flat circuit below. I was coming back to the group to ride on the front some more as it started to sprinkle, so I backed it off a little and BAM, there he was. Long, lifeless red BMC kit not moving or making any noises stuffed into the rail.

Anyway, I’m pretty sure I’d take the slice over wrapping my legs around the support.

looks like a blow out or maybe a tubular came unglued?

That makes me sick to read. Its funny how you watch this and forget that humans had to witness these things first person.

Very sharp, I've known of two accidents personally.

A group I used to ride motorcycles with were riding a local twisty mountain highway and a rider crashed. Hit the guard rail with his legs, think he high sided and it removed both of his legs below the knee.

I was working a bike event where a guy blew a corner going downhill, hit the guardrail apparently twice and was launched over the bridge. It was a downhill turn with a bridge/small creek at the bottom of the turn. One cut was pretty deep like the one in this thread and the second was maybe half as bad... landed on his back on a sandy bank below after flying maybe 75ft.