|
SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Dropped Helmet from Helmet Lock... /cgi-bin/YaBB.pl?num=1312880164 Message started by Wake51 on 08/09/11 at 01:56:03 |
|
Title: Dropped Helmet from Helmet Lock... Post by Wake51 on 08/09/11 at 01:56:03 So this evening I got a case of the butter fingers. I knew it before it happened. As I was adjusting the chin strap to lock it into the helmet lock, I dropped my full face bell helmet onto the pavement. Now I know that dropping a helmet generally means replacement, but in this scenario I just have to ask. It was dropped onto an asphalt parking lot. Visual damage is only a few tiny minor scratches where it landed on some tiny bits of gravel. I just want to know if this drop means automatically replace it. I mean in THEORY without seeing visual damage, it seems like such a 1.5 foot drop shouldn't cause damage and warrant replacement. But then again I always take very very good care of my helmet and even letting others try it on makes me sweat. Opinions will make decision one way or the other easier, even if they are overwhelmingly for replacing it. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by drums1 on 08/09/11 at 05:40:17 From what I've read on the internet, some helmet manufacturers will inspect your helmet if you suspect damage. Certain cleaning solutions, chemicals or heat can degrade it's protective qualities. It should be replaced every 2-3 years reguardless. If you are very particular, as you stated, I would just go ahead and replace it, for peace of mind, if nothing else. Personally, I don't wear a helmet anyways, but if I did, I would just ride as is. Doesn't sound like it was a horrible crash. Gyrobob?? |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by babyhog on 08/09/11 at 06:22:08 I fumbled mine out of my hands one day, from about waist high. Landed on the face shield, scratched the shield a little, maybe a few other minor marks. I didn't replace it. Personally, I think its a way for them to sell more helmets, if its preached that any bump can cause damage. Obviously we are talking about our heads here, and want them as safe as possible. But maybe I'm a little riskier than others. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by MrBrownTX on 08/09/11 at 06:26:13 I have to agree with babyhog. I would think it would have to be a pretty crappy worthless helmet to be rendered useless after a light drop from a short height. It's not like you crammed it into the ground as hard as you could. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by verslagen1 on 08/09/11 at 07:19:45 I wouldn't worry about a plastic helmet at all. But a fiberglass or carbon fiber I would inspect closely. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by Serowbot on 08/09/11 at 09:25:35 Legal liabilities aside,... if it's just scuffed and not cracked, the fall wasn't far enough to compress the inner styrofoam padding.... I'd just keep wearing it... For me,..buying a new helmet, almost guarantees that I'll drop it and scuff it up... If you go down,... even gently, and give it a bonk while your head is in it,... then,.. I give replacement a much more serious consideration... JMO... ;)... |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by CalisOsin on 08/09/11 at 11:00:12 I've always heard you should replace it after a 3ft or high drop. The reason is not so much the out layer, but the foam inside. It's really only made to compress once. Instead of cradling your head (which would cause your head to bounce around and hurt your brain) it absorbs the impact when compressing. A couple light scratches and foot and a half drop I wouldn't bother replacing. But as mentioned earlier, be careful with the cleaner you use to clean up those scratches. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by justin_o_guy2 on 08/09/11 at 15:13:47 You cant compress the foam by dropping the helmet,, thats done when the head crushes the foam when the helmet hits something. IDK how fragile helmets are, but if I thot my helmet would be ruined from a 3 foot drop IDK what Id do... Blasted thing needs to be tougher than that.. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by PiaFea on 08/09/11 at 15:57:13 There is nothing inside the helmet to compress the styrofoam inside with the hard case. Inspect the outer layer and inner foam. If no physical damge beside the outside scratches, I would keep wearing it. Mostly, follow your intuition and feeling. If you feel safer wearing a new helmet, then buy a new one. Do not let that bother you, especially when riding :) Safe and enjoy riding! |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by arteacher on 08/09/11 at 16:06:47 697A6D6C737E787A712E1F0 wrote:
+1 The protection that a helmet provides is from the foam in the helmet. Dropping it a short distance does not damage the foam. A scratch on the surface that does not penetrate the finish does not compromise the integrity of the helmet either. If the shell is cracked (sometimes hard to see), or the foam has been compressed the helmet is no good. BTW the reason why helmets have a "life" is that the foam itself deteriorates, or hardens, after time, and does not compress properly when you need it to. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by Wake51 on 08/09/11 at 16:49:16 There is actually some fraying on the chin strap which was to the point I was going to ship the helmet off to the manufacturer and see what their warranty would do for it. This makes a good motive to that and while it's there, I can have them inspect it for damage. Who knows, maybe they'll just send me back a new shiny helmet! I'm not sure if a chin strap is something that can be replaced. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by WD on 08/09/11 at 18:31:36 Chin strap replacement is easy, quick, and cheap. Most of my helmets have survived being thrown, and I mean thrown, across parking lots, into pickup bumpers, or into tree trunks. I have a 1/2 shell from the 60s that I still use when I have short hair (orange, matches the bike). Cork lined police helmet. A lot more comfortable than the styro lined modern stuff. My early 80s 3/4 that goes with the Honda project is getting an ensolite liner. With a bandanna over the foam. Can't have a blue liner in a green/black/gold helmet... ;) Drop damage is a scam. More sales means more kick backs for greedy Democrats. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by MrBrownTX on 08/10/11 at 08:30:40 0013570 wrote:
I love it, and can't commit to disagreeing with that, lol. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by CalisOsin on 08/10/11 at 09:22:45 415E585F42457444744C5E52192B0 wrote:
How do you qualify that statement? The outer shell can easily flex and dent the foam from the outside, thus subtracting from it's compression area. Just because it didn't crack doesn't mean the plastic didn't dent in momentarily. I still don't think this guy needs a new helmet because this probably didn't happen in his case, but it can absolutely happen from a higher drop. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by verslagen1 on 08/10/11 at 09:58:16 53717C79635F63797E100 wrote:
How do you qualify that statement? The outer shell can easily flex and dent the foam from the outside, thus subtracting from it's compression area. [/quote] Helmets are designed to protect the wearer from an impact. Let's call this impact 20 g's for simplicity. Average wearer maybe 200 lbs. So 20 times 200 = 4000 lbs (slugs... but let's not go into that) This is distributed over an approximate 6" x 6" area 4000 times 36 (let's say 40) = 160,000 psi yeah, I think the foam gonna crush. Now compare that with an empty helmet (ok, no snide remarks... yeah I mean you) Average helmet maybe 3 lbs. So 20 times 3 = 60 lbs This is distributed over an approximate 6" x 6" area 60 times 36 (let's say 40) = 2400 psi I think the impact resistane of styrofoam is something like 8,000 psi... depends on the foam. 2400 << 8000, not going to crush. OK that's a perfect world. reality, the helmet going to deflect and push on the foam. The foam having nothing behind it will deflect too. So it comes down to how much does the helmet deflect and how stiff is the foam. If you're worried about this, think about how much pressure you apply to put the helmet it on and how much you crush the foam every time. :o forgetaboutit. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by justin_o_guy2 on 08/10/11 at 10:37:31 495A4D4C535E585A510E3F0 wrote:
How do you qualify that statement? The outer shell can easily flex and dent the foam from the outside, thus subtracting from it's compression area. [/quote] Helmets are designed to protect the wearer from an impact. Let's call this impact 20 g's for simplicity. Average wearer maybe 200 lbs. So 20 times 200 = 4000 lbs (slugs... but let's not go into that) This is distributed over an approximate 6" x 6" area 4000 times 36 (let's say 40) = 160,000 psi yeah, I think the foam gonna crush. Now compare that with an empty helmet (ok, no snide remarks... yeah I mean you) Average helmet maybe 3 lbs. So 20 times 3 = 60 lbs This is distributed over an approximate 6" x 6" area 60 times 36 (let's say 40) = 2400 psi I think the impact resistane of styrofoam is something like 8,000 psi... depends on the foam. 2400 << 8000, not going to crush. OK that's a perfect world. reality, the helmet going to deflect and push on the foam. The foam having nothing behind it will deflect too. So it comes down to how much does the helmet deflect and how stiff is the foam. If you're worried about this, think about how much pressure you apply to put the helmet it on and how much you crush the foam every time. :o forgetaboutit.[/quote] You see that? Huhh? You SEEE that? Thats how I qualify that statement! & Im Danged glad someone else did it, cuz I wasnt gonna waste my time.. OHH,, & dont read that 1st sentence like Im really being mean,, Im just goofin off.. OHH,, & Thanks Versy. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by CalisOsin on 08/10/11 at 11:09:30 That's some fancy math. But the reality of it is, I've seen the tests, and opened up a helmet or two before with the guys at the shop. I'm not saying that I agree that you need to replace your helmet after a 3 ft drop. I'm just saying that it will compress the foam (however little). I can't prove it mathematically, I can only tell you I've seen it. Vers - I appreciate the time you spent explaining that. Justin - Don't worry, I read the first sentence and my feathers still aren't ruffled. I've been around enough to know that most of us here just have our own sense of humor but are rarely malicious. ;D |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by Johansson on 08/10/11 at 17:33:33 I think I read somewhere, on the snell site, maybe on the dot site, that helmets must be able to sustain a drop of 3 maybe 5 feet onto concrete without the helmet losing any ability to protect the wearer. I was once a student of physics. Or, rather, I went to physics class a lot when I was in college. Actually, I was a physics major, transfered to another university, changed from nuclear to antenna, lost interest after my junior year, became an acountant, now I am a welder, I love it when the architect or engineer comes out and starts throwing math my way,, I can send most of them crawling back to their office. Anyway, at 1.5 feet and say maybe 2 or 3 pounds,,,thats about 4.5 ftlbs of energy. When the helmet hits the ground it has about 4.5 ftlbs of energy it needs to dissapate. I don't know, as I am not associated with any helmet testing organization, how long it takes the helmet to come to a stop from the time of ground contact until the energy is dissapated. On a low energy impact, let us assume, that the impact time is about .001 seconds. 4.5 ftlbs/.001 = 4500 ftlbs/sec That is a pretty big number, might be a tenth of a second, about 450 ftlbs/sec, still a pretty big number. About a horse power, ,,, The foam in a helmet is not protecting by compression, it protects by absorbing the energy of the impact itself. A shock wave of energy, a fairly high energy wave, has been generated by the impact. The foam has elastic bonds, the shock wave breaks these bonds, dissipating the energy within the helmet, before the energy can be transmitted to your skull. High energy impacts will destroy the foam, the helmet is designed to do this one time. Check with the company that rated your helmet for the answer to your question. Yea, I wear a helmet, always,, the energy levels from head to concrete impacts is on the order of several magnitudes larger than a 1.5 foot drop, and helmets are designed to absorb a tremendous amount of this energy. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by arteacher on 08/10/11 at 18:45:44 "The foam in a helmet is not protecting by compression, it protects by absorbing the energy of the impact itself." Not so: The foam in the helmet protects your head by allowing your head to decelerate gradually by compressing the foam when the helmet contacts something and stops, or slows to a stop quickly. It acts as a cushion. It is the shell of the helmet that protects against the impact. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by justin_o_guy2 on 08/10/11 at 20:12:06 Compressing the foam = allowing the foam to absorb the impact, like crumple zones on a car. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by Johansson on 08/11/11 at 03:11:30 From Snell l http://www.smf.org/helmetfaq#aDroppedHelmet Helmets work like a brake or shock absorber. During a fall or crash, a head is traveling at a certain speed. Since the head has weight and is moving, there is a certain amount of energy associated with the moving head. When the helmet along with the accompanying head impacts an unyielding object, a rock, a wall, a curb or the ground, the hard shell starts by taking the energy generated by the falling helmet (head) and spreads it over a larger portion of the helmet, specifically, the internal foam liner. The foam liner then starts to crush and break which uses up a lot of the energy, keeping it from reaching the head inside. Depending on how fast the head is traveling, and how big, heavy and immovable the object is, the faster the head slows down, and the more energy is present. In short, everything slows down really quickly. A helmet will effectively reduce the speed of the head by breaking and crushing which reduces the amount of energy transferred to the brain. The whole process take only milliseconds to turn a potentially lethal blow into a survivable one The key here, "crush and break" Read the top paragragh on the Snell link, looks like the helmet in question should be undamaged and safe to wear. |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by Serowbot on 08/11/11 at 10:17:03 30363D20363E3F60550 wrote:
All this talk of "the head".... kinda' makes me uncomfortable... :-?... |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by babyhog on 08/11/11 at 11:46:31 7563746971646972060 wrote:
All this talk of "the head".... kinda' makes me uncomfortable... :-?... [/quote] Sounds like you need a new "helmet"... 8-) |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by kimchris1 on 08/11/11 at 18:38:38 Myself, I wouldn't replace it. From that distance, a little drop is nothing like slamming your head down on the pavement. Now if you were riding and went down, hitting your the helmet (head) against the pavement, then yes I would. In fact I did.. I slammed so hard my shielf flew off. Helmet was replaced before I ever rode the bike again. I never had any doubts about replacing it. Then again, your helmet, your choice to whether you replace it or not.. You need to feel comfortable that your helmet is going to do the job, if it is ever needed to do. Hopefully that never happens to you. :) kim |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by SuperSavage on 08/11/11 at 19:50:28 When in doubt, throw it out! But to be honest, your situation sounds like a scratch rather than damage to the structural integrity . |
|
Title: Re: Dropped Helmet from Helmet Lock... Post by built2last66 on 08/12/11 at 19:44:31 mine fell off the handle bars, onto the black top, bounced, and then rolled 3 times.. should i get a new one?? Fulmer D5 |
|
SuzukiSavage.com » Powered by YaBB 2.2! YaBB © 2000-2007. All Rights Reserved. |