jyl

This is a really impressive crash. Basically these guys are hammering at over 30 mph, suddenly one is launched over his bars and the bike goes skyward like a rocket, it ends up with the wheel destroyed, carbon fork snapped off, and downtube fractured. See if you can determine exactly what happened and when everything broke.

https://youtu.be/iV9_i9MEnMg

Any thoughts on how you'd avoid this?

StephenH

See this thread on the same video:
https://www.bikeforums.net/road-cycli...-paceline.html

Jeff Wills

Relevant frames are around 30-31 seconds in. Just before the launch, I see road debris, possibly a length of black-painted aluminum. I surmise that the debris got sucked into the wheel, jammed behind the fork, and caused the launch/destruction/snappage.

The rider's pretty lucky to live through that. I'm going to guess that the forks snapping off saved him from being launched even higher.

I try to avoid riding over road debris. I while back, I ran over a branch with my front wheel. I jumped up enough to get sucked into be back wheel, causing it to lock up, putting on my butt. Since I was riding my recumbent, this wasn't a long fall. If I hadn't hit my elbow on the ground, I could have even saved the cup of coffee I was carrying in my left hand.

JTGraphics

First noise is his front wheel running over that flat metal bar you can see it kick up and flip right into is front wheel and thru the spokes and that second noise is it coming around and hitting the fork and instant lock up looks like most of the damage came from the landing as the bike was still on one piece going up.
Glad it looks like he really did not get hurt bad as he tumbled very smoothly and no real hard impact but I'm sure it hurt! bike looks like it took the worst of it.
Some really good riding from the guys all around him and the guy right behind was looking down when it all started, great reaction from him to avoid getting caught up in that and doing further damage to the rider that went down the bike almost landed on that one gut in the road.

Andrew R Stewart 

Thoughts on avoiding this?

Sure- Don't jam along behind another who isn't taking care of those behind. Andy.

loimpact

Whew! That's rough!

Several months ago I hit a large rock. (shoebox size!) I recall that I *intended* to dodge it, but at the speed I was traveling, my reaction was not emphasized appropriately. A new tube, tire & pair of shorts later, I was fine.

I have since made it a priority to be sharper about dodging such objects. (even those I'm not 100% sure of on approach) I also try to do so in a manner that is fluid and not too abrupt. It's difficult but I liken it to the way I learned riding clipless. It starts as very consciously reminding oneself repeatedly, until it becomes habit.

Nevertheless, I know my fate is in other's hands when I'm in a peloton flying down the road at 28mph!

CliffordK

Whatever Anthony was following, taking the film likely likely hit the bar first, making it bounce into Anthony's wheel. It would seem difficult to pick up a bar like that with the front wheel with just running over it, and not using fenders.

The forks were at least mostly attached to the bike while it was flying through the air. It was only about the 3rd bounce that they fell off. They were probably structurally damaged by the initial event, but the "snap" probably didn't save much.


See the other thread for more notes. Is this "Mechanics"?

Doohickie

People keep saying that, but if you look at the video a few frames at at time, the bike appears more or less intact until it lands out in the traffic lane at about 34 seconds into the video. There are several frames after the rider goes down where you can see the front wheel is attached in the normal position on the bike up until the impact at 34 seconds.

EDIT: CliffordK beat me to it.

jyl

I looked at the video frame by frame (there is an extension for that in Chrome).

The bar piece of debris actually goes into the spokes. I was unsure about this, from the video it isn't entirely clear if the bar could be stuck behind the fork crown, but someone pointed out that at the end of the video you see the front wheel with spokes sheared at the rim.

The forks do not separate until the bike comes back down and hits the ground.

The damage to the downtube is, I think, from the bar flailing around. But not sure, could have been from the impact with the ground.

The rider didn't see the debris because he is drafting the rider with the camera.

Does anyone think a higher spoke count wheel makes this sort of thing less likely?

FBinNY 

Less likely, yes. Impossible, No.

More spokes shorten the time window between each spoke, so it becomes more likely that the object would hit a spoke and be flung back rather than pass into the wheel. In some ways it's analogous to how the a smaller hoop can make it almost impossible to sink a basket ball (the old carny trick).

Those who like to see stuff for themselves can experiment by trying to throw a ping pong ball through a spinning wheel. It becomes a question of the speed of the ball vs. the time between spokes. It can be quantified mathematically, but I'll leave that to you.

The only real way to avoid this is to not ride over the end of a bar or branch in the road. If you must hit it, aim for the middle so you don' flip it up.

Doohickie

I'm not convinced the bar went through the spokes (as opposed to kicking up between the wheel and the downtube).

FBinNY 

No one is trying to convince you. But consider that only a significant breaking force could launch the rider over the front. So if the bar didn't go through the wheel, what caused the endo?

Homebrew01

Magic ?

JohnDThompson 

I suppose it's possible that the debris could have jammed between the tire and the downtube.

Leebo

Learn to bunnyhop. Works well in applications like this.

Number400

A strip of metal like that took down the Concorde fleet! Glad he was mostly unhurt. It was a crazy and violent crash and really bad luck. I imagine that one can ride over most debris without the front wheel jamming like that. I had a similar crash in a race but I hit someones torso while hard on the brakes and getting pushed from the rear. In hindsight I should have bunny hopped like Leebo suggested.

intransit1217

My theory: Faulty fork triggered by object. Perhaps the same could have happened with any object or maybe a road marker could have pushed it over it's weak point.

But I know nothing of carbon. So, grain of salt, y'all.

cny-bikeman

1. Watch the road ahead - that was a huge piece of debris in the road, easily avoided ahead of time.
2. Unless on a freeway (extremely rare, as usually illegal) don't ride in a bike lane. They collect debris because the cars sweep all the junk just outside their path.

fietsbob

Touring to see the countries and the countryside, for months. [Europe, British Isles.)

Riding at less than 1/3 of that rate of speed, was my Approach to cycling more safely..
avg 10mph x 6 hours I'm 60 miles further that day ..

And stopping to talk to people along the way .

I just didnt emulate racers.. in my cycling..



Do as you wish.

cny-bikeman

With that logic your bike would be totally safe if you did not ride at all.

Jarrett2

Looks pretty clear what happened. He ran over the tip of a piece of metal and it (against all odds) spun around and went through his spokes. Once it rotated up to the back side of the fork, all wheel motion stopped and the gymnastics began.

He looked extremely fortunate as it appears he almost completely cleared his head on the flip and landed on his butt. A little bit slower of a pace and that would have been one evil face plant.

dbg

And I like the theory that the leading bike (the one video-ing the event) ran over it first --causing it to hop up enough to engage the wheel/spokes. My first impression was that something fell off the lead bike and bounced into the spokes.

LesterOfPuppets

Except out in these parts where it's only illegal in big cities.

JohnDThompson 

Only if you see the debris in time. If you're drafting closely, this may not be the case.

Leebo

I don't paceline, race or draft. Works well mt biking or commuting.