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Miguel Ángel López’s and Chloé Dygert’s time trial crashes – VeloNews.com

Miguel Ángel López’s and Chloé Dygert’s time trial crashes – VeloNews.com 2020-10-06Leave a comment

electrical bike Miguel Ángel López’s and Chloé Dygert’s time trial crashes – VeloNews.com

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Have a query for Lennard? Please electronic mail him at veloqna@comcast.net to be included in Technical FAQ.

Pricey Lennard,
Will we even be having a forensic crash reconstruction of Miguel Ángel López’s recent Giro TT crash within the subsequent Tech FAQ as we had of Chloé Dygert’s crash within the worlds time trial?
— Matthew

Pricey Matthew,
Positive, I’ll offer you my tackle López’s crash. Not like Dygert, he was not going for the win, and which will have had as a lot to do with it as something. He was in all probability simply making an attempt to cruise the TT and save his matches for stage wins later and/or serving to Fuglsang within the mountains.

It was windy, and the street was bumpy. Slightly than specializing in getting as a lot velocity as doable and aggressively pulling on the bars whereas pedaling laborious, which might have concentrated his weight on the elbow pads and the saddle, he as a substitute appeared extra centered on safely making it to the road. He appeared to pretty passively raise his elbows off of the elbow pads and his butt off of the saddle on the identical time, unweighting each wheels whereas coasting, standing on his proper foot.

He moved his proper hand to the bottom bar and had lifted his left arm off and was within the technique of shifting it to the bottom bar as effectively when he lifted his butt off the saddle (presumably as a result of he noticed the bumps he was about to hit). Along with his left hand off of the bar with out both elbow (or his butt) firmly planted, hitting the pair of bumps brought about him to fall down onto the entrance of the bike. His left elbow fell down onto the bottom bar, inflicting the bike to swerve to the best as his chest fell to the bar. All of it went sideways (actually) resulting from off-center weight out on the tip of the left aero bar and left elbow on the left aspect of the bottom bar placing a web torque on the steering whereas each wheels have been free to flail forwards and backwards resulting from not having weight on the saddle or balanced weight on the bar.
― Lennard

Pricey Lennard,
Here’s a state of affairs that occurred to me years in the past which will give some perception into Dygert’s TT crash.

I used to be descending a collection of activates a street known as Palos Verdes Drive East on the Palos Verdes Peninsula. Whereas within the drops on the exit of a flip, I misplaced traction of each wheels concurrently. As a substitute of sliding out, I used to be in a position to reserve it till each wheels connected, which then brought about me to “excessive aspect”. In a fraction of a second, I used to be trying on the street developing at me.

I’ve ridden MTBs together with bikes throughout a stint as a take a look at rider for Honda analysis — I do know tank slappers.

My crash was attributable to both diesel gasoline or transmission fluid. I’ve ridden throughout black ice on a mountain bike. That was an 11 on the “pucker issue” scale. The scariest crashes have been crossing patches of inexperienced filamentous algae. As soon as was a street crossing a shallow culvert throughout a seasonal stream crossing and different a sidewalk that had “greened” from a damaged sprinkler head.

Being that this was in Italy, my guess is diesel gasoline.
— Randy

Pricey Lennard,
Nice assessment of Chloé Dygert’s tank slapper crash.

In Grand Prix motorbike street racing, we see this with inexperienced riders. Essentially the most rapid solution to right a tank slapper on a motorbike is extra throttle, which is counter-intuitive. It’s tough to situation your mind to seize for extra energy, when slowing down appears to be the higher concept. However as you acknowledged in your article, ahead switch of weight is part of the issue.

The opposite trigger/contributing issue to tank slappers, is a slower rotating entrance wheel. As she traveled over the mid-road ripples (you could possibly see them on the video), it could have offset the rotating velocity because the entrance brake was utilized. If she held the entrance brake on, this simply compounds the issue.

Chloe Dygert at the 2019 UCI Road World Championships
Picture: Casey B. Gibson

As , fashionable TT bikes have steep steering tube angles and brief rake. She’s an enormous lady and plenty of weight transferred. Not like bikes, it is extremely tough for a motorcycle rider to generate sufficient new torque on the crank in such a tucked place in order that the burden transfers to the rear tire.
— Tom

Pricey Lennard,
Thanks for the considerate evaluation of Chloé Dygert’s crash. Right here’s an concept that may be complementary to your evaluation and likewise with the experiences of the riders who’ve wobbled whereas cornering on the extensions: An important issue within the sequence that causes wobble to turn into uncontrollable would possibly contain the size (“second”) and mass of a human forearm. If a tire wobbles even as soon as, the forearms swing a bit to 1 aspect. The rider will attempt to management the wobble by way of the forearms, however these efforts will depend upon response time in making use of drive to counter each the forearm swing and the wobble. The forearm swing would possibly, in some instances, synchronize disadvantageously with the wobble of the wheel, the human physique is stuffed with flex and geometry similar to a motorcycle.
— Roger

Pricey Lennard,
This electronic mail is simply so as to add a determine to those in your article. Wanting on the video body by body (25fps), you may see that the oscillation frequency is between 5 and 6 Hz, i.e., it’s within the vary of typical wobble frequencies, and past the human being bandwidth.

In case you are , right here you will discover a careful analysis of on-road shimmy.
— Gianantonio

Pricey Lennard,
Thanks for choosing up this matter — I used to be actually stunned that there hadn’t been every other large press on the trigger.

I’ve a idea that she broke a spoke.

So as to add a conspiracy idea twist, I think her tools producer doesn’t need phrase of this to get out, which is why we haven’t seen any photographs of the bike/wheel and there hasn’t been any announcement from the workforce/rider as to what occurred.

A damaged spoke would result in the as soon as per revolution wobble that you simply noticed, proper? Appears to me to suit the signs.

Is there something you noticed that may make you assume it was not a damaged spoke?
— Jeff

Pricey Lennard,
Has anybody thought of the potential of a damaged spoke as the reason for the TT crash involving Chloé Dygert? It seems to me, a spoke on the entrance wheel failed and brought about the wheel to immediately change form, and consequently made the bike unattainable to regulate within the flip. I’d be taken with your ideas relating to my idea.
Mark

Pricey Mark and Jeff,
Sure, a damaged spoke might have initiated the lack of entrance tire traction that began the tank-slapper. And no, I didn’t see after photographs of her wheels, so I’ve no proof by hook or by crook concerning the integrity of the spokes.
― Lennard

Pricey Lennard,
Thanks very a lot to your column about Chloé Dygert’s crash within the particular person time trial on the 2020 world championships, not too long ago. Simply throwing in a little bit of supporting information: there’s a second simply because the rear wheel of her bike passes the tip of the padding the place the bike (at max oversteer), the roadway, and the padding are roughly parallel and one can attempt to evaluate them. At that second it appears to me just like the padding sections are about 2 bicycle-wheelbases lengthy, or maybe a bit extra. That appears to help the high-speed wobble conclusion you got here to.

I actually hated to see her wreck so badly, and whereas driving so effectively in addition! It might have been great to see her repeat the title. I’m actually glad her accidents is probably not as extreme because it regarded initially.
— Greg

Pricey Lennard,
I loved studying your evaluation. One information level that I can add is the guardrail spacing. From what I can inform from researching Italian requirements, the size of the steel panel is 4 meters (splice heart to heart). The usual I noticed indicated posts on the overlap of the panels and likewise on the midpoint for a 2-meter spacing (US spacing is 12’6″ for the rail splice to rail splice and 6’3″ for publish spacing).

My video shouldn’t be that clear however there could also be an intermediate (2m spacing) publish on the method nostril of the rail on her left. The place the automotive stops it appears to be on the 4m spacing. This can be helpful for figuring out the nook entry velocity if the railing joints/posts are visible enough.
— Tim

Pricey Lennard,
My $0.02 on Chloe’s worlds TT crash from which I hope she has a quick and full restoration.

An element deserving further dialogue is the movement of Chloé’s saddle beneath her through the wobble. After I first noticed the video, I believed she was really standing up on the pedals, however after watching it just a few instances, I consider she acquired bumped up off of the saddle, reminiscent of by a bump within the street or by a momentary loss (or acquire) of traction within the nook.

Why is that vital? Let’s return to the times of comparatively versatile frames. As an aspiring junior racer, I used to be taught to stop or counteract a velocity wobble on a quick descent by clamping my knees on the highest tube. I hypothesize what this does is to stiffen the rider-bike system concerning the steerer axis, thereby rising the resonant frequency effectively above the enter frequencies, getting the system away from resonance, and stopping the wobble.

Chloé was flying, she was dedicated to the nook, and she or he was dedicated to staying within the aero bars. In that state of affairs, as soon as she acquired bumped up off the saddle, she misplaced one in every of her essential contact factors with the bike, and being within the aero bars decreased her skill to use torque to the handlebars. The bike’s resonant frequency concerning the steerer axis decreased, and she or he acquired walloped by a nasty wobble at a really dangerous time.

Chloé misplaced her likelihood at rainbow stripes this time round, however she confirmed us all what it means to actually go for it in pursuit of them. Chapeau to her.
— Garrick

Pricey Lennard,
I learn your current article about Chloé Dygert’s entrance wheel wobble on her time trial bike, as I’ve at all times been fascinated with TT bikes. I’ve by no means ridden one, so I don’t know how they deal with, and my query might be ill-informed. Why are the entrance ends so brief and steep on these bikes? Would an extended, slacker bike not be extra environment friendly for a TT if the rider might keep within the extra aerodynamic place for longer?

Picture: courtesy Trek bicycles

I copied some side-view pictures of Trek’s SpeedConcept time trial bike and Madone street bike, and you’ll see how the rider’s arms are at all times in entrance of the entrance tire’s contact patch. That is in distinction to a typical street bike, which solely has the rider’s arms in entrance of the contact patch when means up on the hoods (a place I’ve at all times discovered to be sketchy on descents). In fact, a mountain bike locations the rider’s arms means behind the tire’s contact patch.

Perhaps I’m specializing in the unsuitable element, I’m simply making an attempt to determine why these bikes are designed the way in which they’re when it appears like they’re about to ship the rider over the handlebars at any second.
— John-Paul

Pricey John-Paul,
Sure, an extended entrance finish might add extra stability to the bike, and the aero bar and ahead saddle transfer extra weight to the bars. On taller bikes (not in all probability taking part in a job with Dygert’s bike), one limitation to entrance finish size is the UCI most front-center dimension of 65cm (see diagram). When mixed with a steep seat angle pulling the underside bracket again and an extended prime tube, the entrance finish should be reeled in fairly a bit to satisfy this customary.
― Lennard


Lennard Zinn, our longtime technical author, joined VeloNews in 1987. He’s additionally a {custom} body builder (www.zinncycles.com) and purveyor of non-custom large bikes (bikeclydesdale.com), a former U.S. nationwide workforce rider, co-author of “The Haywire Heart,” and creator of many bicycle books together with “Zinn and the Art of Road Bike Maintenance,” “DVD, in addition to “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.” He holds a bachelor’s in physics from Colorado School.

Observe @lennardzinn on Twitter.

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