post #91 of 149
3/6/08 at 9:58am
Sounds like a sweet place to live! Hey, look at the bright side.... You are only a 3 HOUR drive from skiing!!!
|I'll check in on this thread this afternoon.... I have to go take my daughter to Kindergarten registration and orientation, then we are going to ski for an hour before I head back to work. I love Iowa!|
Skiers can reduce their risk of death dramatically by not skiing fast in the vicinity of trees. No other protective measure can equal the effect of not slamming into the tree to begin with! We recommend that skiers avoid slopes with trees, rocks or unpadded lift line pylons, as well as slopes where other skiers jump without being able to see their landing spot.
The key is a sweet helmet like this:
...and "angry looking" goggles.
Look at the lady in the background.... she's snapping a picture of Richie and texting her friend back home... "you wouldn't believe this freakin' dude here at the hill.... Yeah, he has on Darth Vader looking helmet, and some type of strange devices strapped to his jacket.... I attached a picture! I saw him on the hill earlier, I think it might be his first day skiing. Too bad all he has is his snowmobile helmet to wear."
(obviously just speculation. That is only one thing that she MIGHT have texted. This does not necessarily represent my view or opinion)
To my knowledge POC didn't certified their helmets with Snell because the fact that they didn't test penetration.
But RR why not call R&D on POC in Sweden and ask them for the facts?
I was talking to one of our race coaches about the POC hype and he stated that they are having structural failures in the chin bar/ear piece area. He said that they're fine unless you mount the slalom bar and start taking some hits on it. He advised to hold out until they undergo more R&D to solve the problem. GS use of the 2007/08 models should be ok since most do not use a chin bar.
Sounds like a fragile helmet.
Wow, I've been away from a computer for a while, and come back to four pages of this.
One point seems to have been overlooked: Helmets, first and foremost, are supposed to (a) protect your brain from banging back and forth inside your skull and (b) protect your brain from something penetrating it.
Whether they suffer cosmetic damage, or even split into small pieces, is only relevant to that outcome if you can show that the cracks or chinstrap tear or whatever created more trauma. Otherwise, your angst is more about your aesthetics, or your bank account, or your web persona, than basic neurobiology.
Now we've had a lot of other threads about helmets, and a lot of links to good sites. I'm not an engineer who knows everything about everything, but 40 years of motorcycles made me attentive to helmet design, and when I decided to start wearing a ski helmet, I studied up, talked to doctor friends, racers, shop guys about it. What I know is that the various certifications are all about (b), which is a lot less common than (a). Most people's head trauma in a skiing accident is from brain slosh, not from a branch or rock actually penetrating the skull. Yes, penetration will create sloshing, but that'll be the least of your worries.
Moreover, NONE of the tests, including Snell, do a very realistic job of recreating the kind of impacts helmets actually take, because lab tests need to control as many variables as possible so they can be reproducible. Impact is a LOT easier to measure than brain bang. A lot of the helmet sites that talk about certification appear to discount it as a "gold standard." and until I hear about a slope injury caused by a steel weight being dropped on the crown of a helmet, I'll agree.
In addition, brain slosh/bang is poorly correlated to shell design, and in a way that's counterintuitive. That is, a very hard shell that rocked on a Snell test, will actually increase your likelihood of brain damage/concussion because it will efficiently transmit more force to your skull, which will then rebound against the hard shell, and so on. Cracking the shell will actually reduce the amount of force that hits your liner; the shell's done its job.
EPS foam is also fairly rigid, which is why it cracks so easily. That's a good thing, since the fracturing means absorbed and diffused energy. Thus almost all ski helmets are a thin "in-mold" shell designed to crack, and EPS. Just like the bicycle helmet you own. A few helmets that I know of (W, Sweet, one POC model) use EPP, which is softer, denser, and better at absorbing energy. But it costs more, so you know where that song goes. Moreover, the design and placement of "fit pads" also counts toward reducing brain trauma by diffusing energy. A sloppy helmet will help bounce its occupant.
So listen up: If you use a rigid liner, you WANT the shell (and probably the liner) to crack. POC prevents penetration by using a less rigid shell with steel mesh or a genre of kevlar underneath, expects the helmet to die to protect its occupant. If you go with a more elastic foam, you can use a more rigid shell (Sweet uses carbon fiber and thick ABS, POC uses thick ABS) like you see in motorcycle helmets. The top line racing helmets I've studied from others like Marker, Uvex etc. tend to go with a very hard shell (often carbon or glass mixed in) to prevent penetration plus the EPS (which will have microfractures after a hard fall even if the shell looks spiffy.)
Finally, my experience is that that coaches and guys who race actually DO pay attention to this stuff and many can carry on an intelligent conversation about it. They're not just sponsored talking faces, and if a lot of them wear/recommend POC, I'd suspect it means something. POC design is more than marketing hype IMO. They appear to spend a lot of effort to diminish the actual causal variable (brain bang) even if it means more complicated design (like different densities of foam and kevlar underneath) that the masses don't get. They actually study the design of fit pads and where EPS should give way to other kinds of material. If you want to blast someone for marketing hype, blast the majority of manufacturers who give us glorified bicycle helmets and let us think we're covered...
Customer: I'd like to return my POC helmet
Customer Service Rep: Why?
C: It's falling apart and the screws are worthless
CSR: These helmets are guaranteed for one year and we'll be happy to send you a new one. We've never had that happen to our helmets before. It must be a defective product.
C: But it's happening to all your helmets
CSR: That's news to me. I'll be sending out your new helmet today.
(weeks go by and customer finds new helmet and calls CSR)
C: I received the replacement helmet and it still has those same lame a$$ screws and the chin guard fits as poorly as the old one.
CSR: But it's a new helmet
C: But I'm going to have the same problems with this helmet as I did with my last helmet
CSR: Sorry, that's not my problem. I sent you a new helmet because we guarantee our helmets for one year.
C: That's good to hear. So this new helmet has a one year guarantee?
CSR: Of course not, your one year guarantee started when you purchased your helmet, not when you received out replacement. Do you really think we're that stupid?
One point seems to have been overlooked: Helmets, first and foremost, are supposed to (a) protect your brain from banging back and forth inside your skull and (b) protect your brain from something penetrating it
...What I know is that the various certifications are all about (b), which is a lot less common than (a). ...
Originally Posted by One of the certifications the FIS blindly accepts
The performance testing first subjects helmets to a dynamic test of retention system strength or to a test for positional stability. The helmets are then subjected to several impact management tests, to shell penetration tests and to chin bar tests if appropriate. These tests are conducted upon helmet samples either kept under laboratory ambient temperature and humidity or that have been conditioned in one of two environments simulating extremes of the conditions in which the helmet might reasonably be expected to be used.
The peak acceleration of the headform shall not exceed 300 G's for any valid test impact. Similarly, the helmet's protective structures shall remain intact throughout the testing. If the Foundation's technical personnel conclude that the headgear has been compromised by breakage, the sample shall be rejected.
|Thus almost all ski helmets are a thin "in-mold" shell designed to crack|