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Helmets
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#12
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Helmets
yk wrote:
The price range from $10 - $200. What are the differences ? Are expensive helmets safer or more aero-dynamically designed ? What to look for besides fit and color ? TIA As far as I know, all helmets sold in the US meet basic safety standards defined by the consumer protection agency. I believe the standard is Z90 (IIRC), and the helmet liner is marked accordingly. Moreover there used to be a more stringent standard used by the SNELL institute. Helmets with SNELL ratings used to be more safe (for penetration) than helmets that just met the Consumer protection standards. I am not sure if SNELL still exists, but I would suggest that you look for a helmet that has a SNELL rating if you are looking for the ultimate in safety. I would appreciate comments from anyone who knows the current situation, because I am not sure of it. HTH, Ernie |
#13
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E Willson wrote:
yk wrote: The price range from $10 - $200. What are the differences ? Are expensive helmets safer or more aero-dynamically designed ? What to look for besides fit and color ? TIA As far as I know, all helmets sold in the US meet basic safety standards defined by the consumer protection agency. I believe the standard is Z90 (IIRC), and the helmet liner is marked accordingly. Moreover there used to be a more stringent standard used by the SNELL institute. Helmets with SNELL ratings used to be more safe (for penetration) than helmets that just met the Consumer protection standards. I am not sure if SNELL still exists, but I would suggest that you look for a helmet that has a SNELL rating if you are looking for the ultimate in safety. I would appreciate comments from anyone who knows the current situation, because I am not sure of it. I grazed google past this topic about a month or so ago, and I was left with the impression that SNELL does not exist for bicycle helmets (anymore). It's pretty much a motorcycle helmet thing. To the original poster, since all helmets in the US pass the same test, the only real difference is ventilation and appearance. -eric |
#14
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mark wrote:
Am I missing something, or is a cyclist hit from behind by a car going to get accelerated rather abruptly to the car's speed at the time of impact, regardless of closing speed? 40 mph car rear-ending a 20 mph cyclist has a closing speed of 20 mph. 40 mph car hitting the front of a 20 mph cyclist hits with closing speed of 60 mph. I think I'd rather be accelerated 20 mph rather than 60 mph. RFM |
#15
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It is the impact that counts. The net effect of being hit by a 40 mph car,
when you are riding in the same direction at 20 mph, is like standing still and being hit by a 20 mph car. Yes, you will be accerelated plus 20 mph in either case but at a much slower rate. The other case you get hit by a 60 mph car, and then accelerated to 40 mph. BIG difference. "Fritz M" wrote in message ups.com... mark wrote: Am I missing something, or is a cyclist hit from behind by a car going to get accelerated rather abruptly to the car's speed at the time of impact, regardless of closing speed? 40 mph car rear-ending a 20 mph cyclist has a closing speed of 20 mph. 40 mph car hitting the front of a 20 mph cyclist hits with closing speed of 60 mph. I think I'd rather be accelerated 20 mph rather than 60 mph. RFM |
#16
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Helmets
Eric Hill wrote: E Willson wrote: I am not sure if SNELL still exists, but I would suggest that you look for a helmet that has a SNELL rating if you are looking for the ultimate in safety. I would appreciate comments from anyone who knows the current situation, because I am not sure of it. The Snell rating still exists, in that any manufacturer who has a helmet that meets Snell requirements, and who wants to pay to have it certified by Snell, can do so. However, manufacturers seem to have decided en masse that it's not worth paying for that certification. The US law requires CPSC certification, and they're happy enough with that. And I wouldn't call Snell " the ultimate in safety." Snell is just slightly more stringent than CPSC. (CPSC requires a 2 meter drop; Snell a 2.2 meter drop.) The impact speeds are very nearly equal. Neither test has the mass of a body attached to the headform. IOW, the helmets are certified to protect a decapitated head hitting something at 14 mph. Hitting at 16 mph is beyond what they're designed for. Hitting with your body still attached to your head is also likely to overpower the helmet. Incidentally, I think this is why Snell certification isn't popular. If a manufacturer claimed "Ours is more protective! We're _Snell_ certified!!" some consumers would ask "What's the difference?" The answer would have to include a description of the laughably low certification; and once that was given, the jig would be up. Consumers and legislators would realize how worthless the things are. I grazed google past this topic about a month or so ago, and I was left with the impression that SNELL does not exist for bicycle helmets (anymore). It's pretty much a motorcycle helmet thing. To the original poster, since all helmets in the US pass the same test, the only real difference is ventilation and appearance. Not so. As others have pointed out, more expensive helmets tend to be lighter and have better ventilation. That makes them generally less uncomfortable to wear. But it also makes them less protective. Much of the expense in a pricey helmet comes from the extensive computer modeling and testing to get them to be as light and "holey" as possible, but JUST BARELY pass the standards test. The cheaper ones have more margin of protection. They leave in more styrofoam and cut fewer holes so they can be sure it will pass the test without re-designing. So when you pay more, you get better ventilation, but you get less protection. You also tend to get something that looks more like a psychedelic squid wrapped around your head. But there's no accounting for fashion! - Frank Krygowski |
#17
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Helmets
Eric Hill wrote: E Willson wrote: I am not sure if SNELL still exists, but I would suggest that you look for a helmet that has a SNELL rating if you are looking for the ultimate in safety. I would appreciate comments from anyone who knows the current situation, because I am not sure of it. The Snell rating still exists, in that any manufacturer who has a helmet that meets Snell requirements, and who wants to pay to have it certified by Snell, can do so. However, manufacturers seem to have decided en masse that it's not worth paying for that certification. The US law requires CPSC certification, and they're happy enough with that. And I wouldn't call Snell " the ultimate in safety." Snell is just slightly more stringent than CPSC. (CPSC requires a 2 meter drop; Snell a 2.2 meter drop.) The impact speeds are very nearly equal. Neither test has the mass of a body attached to the headform. IOW, the helmets are certified to protect a decapitated head hitting something at 14 mph. Hitting at 16 mph is beyond what they're designed for. Hitting with your body still attached to your head is also likely to overpower the helmet. Incidentally, I think this is why Snell certification isn't popular. If a manufacturer claimed "Ours is more protective! We're _Snell_ certified!!" some consumers would ask "What's the difference?" The answer would have to include a description of the laughably low certification; and once that was given, the jig would be up. Consumers and legislators would realize how worthless the things are. I grazed google past this topic about a month or so ago, and I was left with the impression that SNELL does not exist for bicycle helmets (anymore). It's pretty much a motorcycle helmet thing. To the original poster, since all helmets in the US pass the same test, the only real difference is ventilation and appearance. Not so. As others have pointed out, more expensive helmets tend to be lighter and have better ventilation. That makes them generally less uncomfortable to wear. But it also makes them less protective. Much of the expense in a pricey helmet comes from the extensive computer modeling and testing to get them to be as light and "holey" as possible, but JUST BARELY pass the standards test. The cheaper ones have more margin of protection. They leave in more styrofoam and cut fewer holes so they can be sure it will pass the test without re-designing. So when you pay more, you get better ventilation, but you get less protection. You also tend to get something that looks more like a psychedelic squid wrapped around your head. But there's no accounting for fashion! - Frank Krygowski To continue the thread Thanks for the several replys As you say , the SNELL rating is basically a motorcycle thing which has been applied to bicycle gear. Based on your comments I believe that the impact performance of a CPSC helmet and a SNELL certified helmet is about the same. IIRC the SNELL certification came about because a motorcycle rider named Snell was killed by a sharp metal object that penetrated his helmet, killing him. The helmet he was wearing was adequate for impact resistance. As I remember it, the original intention of the SNELL rating was to improve the penetration performance of helmets. Based on what has been said here, I'd have to assume that if a helmet carried a SNELL certification it would be as good (or better) in impact as a CPSC rated helmet, and it would be more protective against penetation type objects. Does this sound correct? Comments? Regards, Ernie Willson |
#18
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E Willson wrote: To continue the thread Thanks for the several replys As you say , the SNELL rating is basically a motorcycle thing which has been applied to bicycle gear. Based on your comments I believe that the impact performance of a CPSC helmet and a SNELL certified helmet is about the same. IIRC the SNELL certification came about because a motorcycle rider named Snell was killed by a sharp metal object that penetrated his helmet, killing him. The helmet he was wearing was adequate for impact resistance. As I remember it, the original intention of the SNELL rating was to improve the penetration performance of helmets. Based on what has been said here, I'd have to assume that if a helmet carried a SNELL certification it would be as good (or better) in impact as a CPSC rated helmet, and it would be more protective against penetation type objects. Does this sound correct? Well, not really. Snell was an auto racer, and the fatality didn't involve penetration, AFAIK. From the Snell Memorial Foundation website: "William "Pete" Snell died in 1956 because his then state of the art helmet lacked the protective capacity to see him through what was termed a survivable accident. Pete Snell's helmet represented an intuitive solution for impact protection. After Snell's death, Dr. George Snively demonstrated that human intuition is not a reliable guide to understanding crash impact, particularly in the millisecond time domains in which crash impact occurs. Snively discovered that most injuries of helmeted people occurred because the liner had reached full compression, that is, the helmet had used up all its protective capacity, before the impact was over. Helmets were too thin and far too soft. Snively studied auto racing accidents and compared injury versus helmet compression in real world impacts to peak acceleration versus helmet compression in laboratory tests. He concluded that young healthy men could expect to withstand head impacts corresponding to lab tests incurring from 400 to 600 G's. Since tolerances vary among people and are likely to vary with age, Snively set Snell test criteria at about 300 G's. Snively then set up the first of the Snell helmet standards..." Also from that website: " William "Pete" Snell was an amateur auto racer. He died needlessly in a racing event in 1956 when his then state-of- the-art helmet utterly failed to protect him." What's interesting to me is that there have been many deaths of helmeted cyclists, including cyclists wearing Snell-certified helmets! One could say that each of these "died needlessly when his then state-of-the-art helmet utterly failed to protect him." IOW, one could use the same logic to call for a new Memorial Foundation! Seriously, the Snell Memorial Foundation has certainly improved helmet science. I just wish they'd drop the rabid promotion of helmets for activities that are already more than reasonably safe. Like cycling, of course. - Frank Krygowski |
#19
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Helmets
Eric Hill wrote:
I was left with the impression that SNELL does not exist for bicycle helmets Not quite. See the link below for a discussion of the various standards. http://www.bhsi.org/standard.htm Art Harris |
#20
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Helmets
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