Ex Pres 

Not really C&V - but I was glad this young lady was not on a steel frame.

Last night during our ride after a wheel touch she veered off across the center line and hit a car. this was in a neighborhood, and fortunately the car was able to brake, but she still hit it head on.

Carbon frame exploded. The tubes busted at every lug except down the seattube. I'm guessing this helped absorb the impact shock. Helmet pressed into her forehead as she hit the hood, but she stood right up and walked away. Dented and bruised, but OK. Not sure a steel frame would have been so forgiving for her.

Everyone be safe out there!

SingeDebile

steel frames absorb the impact energy differently... basically they usually simply bend, i dont think this means they are absorbing less of the energy of the crash.

Hydrated

Crumple zones built into my bicycle?

No thanks... I'll just try to avoid hitting cars.

banjo_mole 

Hydrated, not "crumple zones," but "crumple lugs."

Thank goodness the lady is okay.

cudak888 

She is lucky her helmet had sufficient forehead protection, first of all.

As for momentum: You are essentially shot forward (or slightly offset) off the bike at the moment of head-on - or slightly offset head-on - impact. The only exception may be if you have your clips set unbelievably tight, in which case you might receive some of the opposing motion; otherwise, the momentum of the bike becomes irrelevant once you have been launched.

That said, a steel frame will usually not survive such an impact either. Sure, it won't disintegrate as carbon would, but it will not survive it. Least you'll get in the accident you describe above is a dent in the downtube, and doglegging.

Someday, I'll show you a nice little photo essay of my wrecked Guerciotti, soon as the insurance is resolved on that thing.

-Kurt

TRaffic Jammer

I don't think this miracle of material physics will make into the marketing of CF frames.
She should just count her lucky stars and go buy a lottery ticket.

cudak888 

Lottery ticket? How about a course that teaches her how to hold a line?

-Kurt

FZ1Tom

I would have to second what cudak said - or if still inexperienced (as I would be in group rides) then don't ride so closely together in the first place.

what brand was it, and is she going to replace the bike, etc? I'm just having a little trouble visualizing this gal standing up and walking away without a few choice words about the demise of her bike!

Tom

cudak888 

Nothing in Jim's thread suggested she was riding too close. She was riding contraflow.

-Kurt

krems81 

I think she veered off after their wheels touched.

TRaffic Jammer

I'm flabbergasted that they were riding in such a way that this could even happen but I didn't wanna rail on the obvious bad positioning/riding. Glad somebody did though. Glad she's OK....never should have happened, even with a wheel touch. If wheels were touched, then, yes, too close... don't tell me they were drafting in a neighborhood.

Zaphod Beeblebrox 

I'd bet the driver had some choice words about the condition of his hood too.

We usually don't ask this around here but... what happened to the car? If there's damage I would expect she'd be responsible for it. If it were a steel frame it would have likely put a nice sting on the car. I mean its obviously not the driver's fault.

thenomad

As in F1 racing, the problem with CF "exploding", is the sharp shards created. With steel this is not the case. Both bikes would have crumpled. Crumple zones don't necessarily protect the rider in an impact as far as i can tell. If that were the case we'd have to wear seatbelts on our bikes to keep our bodies safely in the crumple zone.

She's lucky.

TRaffic Jammer

In F1 the 'shearing' effect of the CF components is too rid the "cage" of protrusions that can cause the safety cage to roll/pinwheel/stop dead by sticking to something like a wall/another car or digging into the ground, as well to prevent skewering another driver. The nasty splinters , are ...well, nasty splinters, with all the evilness associated with high speed sharp things. Definitely worse than running with scissors.

due ruote 

+1
Among other things, lucky that the vehicle she happened to hit had a hood low enough for her to maintain forward movement.

bikemore 

I hit a car that turned in front of me. Both going at slow speeds. I went over the hood and got up and
walked away. Steel tube bike had the crumple that said don't ride me again. Guess it isn't quite the same
thing, but... As others have said I don't think the carbon frame did much to save her. Wearing a helmet definitely
is useful, although unfortunately not in all cases.

Ex Pres 

Traffic, we were in more of a "loose group", rather than drafting. No issues while we had been pacelining earlier. This was near the end of the ride and no one was really pushing it. But guards were down. There was a choice of two quick left turns coming up, some confusion up front as to which turn we were taking, and as everyone's concentration level was a little relaxed, small confusion in the lead led to an unfortunate chain reaction further back.

I really didn't want this thread to be about causes, just the result. I had a wreck on steel 35 years ago. I didn't walk away. Maybe I wouldn't have on CF, either.

And she already had a new frame on order, amazingly enough. She won't be reusing her old fork now, though.

TRaffic Jammer

cool cool , wasn't going for a who did what-let's-blame breakdown but a good-to-know the why......
Yes... those sit-up-which-way are we going moments.... been there alright.

Glad she's OK. Musta freaked the driver though....

RobbieTunes

My Kestrel-riding speed fried of about 25 years, winner of many a criterium and road race, has always been a go-to guy for bike advice (non-C&V) and riding advice. I've never seen him without a helmet, and he, even at 54, is addicted to speed, clip pedals with 3 straps, and I've never seen him unclip, either. Somehow, he stays up on that thing.

Friday, he called from the ER, having been brought there by EMS. His L pedal came off the bike and he flipped it, pivoting around the top tube. 12 staples to the back of his head, NO HELMET.
40 years of riding, including seeing a rider he was training get a concussion and skull fracture in a similar single-bike wreck.

I wear 'em. I may not like 'em, but I wear 'em. Glad the lady is OK, and she prepared for being so.

miamijim

Things happen in life.....



Crumple zone increase the distance and time at which energy is dissipated thus reducing the overall forces of the impact.

f=m*v2 or f*m/(s-s/t-t)

Increasing the denominator (t-t) by prolonging how long it takes to stops leads to decrease in overall force. Decreasing the numerator (s-s) by increasing the distance of stopping leads to a decrease in the overall force.

If your have an impact against a wall with your head the overall distance of decelleration is short and the time it takes to stop is very short. A helmet with 1" of foam increases your stopping distance from almost 0" to 1" and increases it increases the time it takes to stop. Crumple zones at work.

ginsoakedboy

I think the OP is absolutely right, and this is the first persuasive argument I've ever heard in favor of carbon. I think every CF frame should be taken out immediately and run head on into oncoming traffic.

cudak888 

-Kurt

subclavius

Carbon frame bikes:

Lighter weight-$3,000
Impress your friends-$4,500
Explodes on impact-priceless

banjo_mole 

I'm gonna get a helmet.

cs1

Sad thing is, I believe he's really sincere about what he said. Somehow I can't believe an exploding frame saved her. I'm thinking it had something to do with the helmet.