Helment Damage.

So of course you’re now going to start wearing a full-face helmet, since it’s his face shield that’s cracked.

well the reason i noticed it 5 days after is right after the crash i just stood up and dusted my self off, checked to make sure everything was ok, then i got back on, rode home, and when i take my helmet off i dont like put it in a cabnient or soemthing so i just kinda chucked it onto the ground and didnt look at the back.

Re: Helment Damage.

“tholub” <tholub@NoEmail.Message.Poster.at.Unicyclist.com> writes:

> All I am saying is that it is an obvious physical fact that you’re
> more likely to hit your helmet than you are to hit your unprotected
> head, therefore the fact that someone hit his helmet in a crash
> doesn’t mean that he would have hit his head.

What you wrote is: “Let’s be realistic … [hitting your helmet] is
not at all proof that you would have hit your head.”

That’s pretty strong wording in my book, so I assume you have an
anti-helmet prejudice. Admittedly that’s an assumption on my part.
If I am wrong, just say so. Either way, it is fair to assume that I’m
not the only one who read it that way, so pro-helmet responses seem
right on target to me.

And yes, I have a pro-helmet bias. The issue came up in R.S.U a while
ago. I searched for credible evidence that helmets actually do
measurable harm in low energy impacts and, despite lots of noise from
anti-helmet folks, could not find any support for the notion. I did
find a paper by bicycle dsafety experts from a university in the UK
systematically refuting the claims.

Lastly, getting back to being “realistic”. I’ve hit my helmet many
times and have yet to create a tear in the shell that large. Based
just on the damage to the helmet, I have to conclude that Evan was
fortunate to have been wearing it.

Ken

Helmets

A helmet which is not used damages the wallet with a low energy impact. Helmets suck!!! Notice that no “Unicycle safety experts” systematically refute any of the claims. Bicycles and unicycles are completely different vehicles, hence the laws for wearing helmets on bikes not unicycles.

I already wear one when doing DH mountain biking, you’d be stupid not to.

Why would one compare the size and mass of a helmet to that of the human body? Last time I checked, most people wore helmets just on their head.

Which engineer are you talking about? Yourself? I would have a problem making such a statement. There are 1,001 ways to smash a helmet, and 1,001 ways to smash your head, but the two events are not 100% correlated.

…especially since Evan’s involved. Frankly, I’m a bit skeptical about that guy’s claims. Call me a critic, but I still don’t believe he broke his helmet doing a backflip down three stairs.

‘hence’ is IMO not the appropriate term there, as it states that there are no laws for unicycle helmets because they are completely different to bikes.

The real reason there are no helmet laws for unicycles is surely because the law hasn’t turned its attention towards them, due to them being possibly the least used form of transport.

Head Impact Graph

I thought I would add some more fuel to the fire on the helmet debate. I have included a graph on impact survival experience from NASA-STD 3000. One point that you should note is that a head impact from a standing position (no added riding velocity) is on the edge of survivability. This assumes that the person’s head is the first thing to hit the ground and the ground did not absorb any of the impact (concrete). Hope this helps with your debate.

Because a poster above was talking about center of mass. The COM of a person would be essentially unchanged by adding a helmet. As far as size goes, the size of the body compared with the size of the helmet means that the helmet is way less than 1% of the volumetric footprint of the body. So as far as an accident goes, the size of a person is unaffected by a helmet. Therefore, the class of accidents is unchanged by the addition or deletion of a helmet.

Yup.

Why do you think 100% correlation is required? If a helmet saves death or injury in a reasonable subset of accidents (it does), then it is worth wearing.

Ah, but there you get into the tricky part. You are more likely to have a head injury in a car accident than in a bike accident (even with a seat belt), but to suggest that people wear helmets in cars is considered ridiculous. Similarly, pedestrians get head injuries in a reasonable subset of accidents, but no one thinks of advocating for helmet usage for pedestrians.

The helmet debate is much more about perception of risk than it is about actual risk. That’s not to say that helmets don’t reduce risk; they do. But the lines people draw about where helmets “should” be worn are largely arbitrary.

You’re failing to recognize that the dynamics of the human body are far different than that of a rigid body. The head is not rigidly attached to the body (or, for some, not attached at all) and is free to move with at least three degrees of freedom, constrained by the attachment at the neck.

Adding a helmet to the head increases its mass significantly (when you consider just the head). As the helmeted head accelerates during an accident, the neck will be subjected to more stress and strain than normal. One’s head does not have to be impacted to get it to accelerate, so in some cases, a helmet can cause more damage than it can prevent.

Note I am not discouraging anyone from wearing a helmet, but I would like to point out that it is not 100% safe. It is every rider’s personal decision to risk permanent, irreversable brain injury; wear a helmet now or a drool bib later, your choice.

I don’t… your original post was a very blatant statment, in effect: “An engineer says if A then B.” Such a statement implies 100% correlation. Your “an engineer” qualification lends no weight to your witless deduction, and offends other engineers / physicists / scientists / people of good taste. :stuck_out_tongue:

Anything that is not used is a useless impact on the wallet, a helmet that is not on a head is unused, not one that isn’t hit or damaged. I’ve lost track of the number of times that a branch scraped on my helmet while MUning but, while there wasn’t any damage to the helmet, I consider that to have been part of the reason that I wore the helmet and well worth the cost.

Sounds to me like you have an attitude problem and please don’t try to confuse you with facts.

Hmmm, lets see

> they both are powered by a human, pedaling
> they both are ridden by an unprotected human (a passenger in a car is protected, a cycle rider is not)
> many of the parts used on one are usable on the other.
> the frames are made of the same materials, you can even make a unicycle out of a bike
> it’s possible to ride a bicycle in the same fashion as a unicycle.

So, just how much congruence do you need? Is it not the same because it has a different seat? – men’s and women’s road bike seats are different these days. They ARE similar, not identical, but very, very similar. Road bikes, trikes (I have a $4000 road trike), and mountain bikes are not the same, either. The only reason that there are not laws (and in many places the laws that apply to bicycles apply to unicycles {including helmets}), specifically for unicycles is that there is not enough of them to have come to the attention of the law makers as being different from bicycles. There aren’t many (any?) laws that specify road bike, trike, or mountain bike either.

I personally don’t want ANY laws about what I have to do for my personal safety, I don’t believe the government, any government, has the responsibility or authority to do that, if someone does something stupid and get themselves injured or killed, it’s their fault and responsibility, not the governments. If the government is supposed to prevent us from doing something dumb, then we’ll find that we can’t do ANYTHING - breathing is dangerous (you might swallow a fly) and should be prohibited. That said, laws protecting children are what government is about and are appropriate – children, by definition, do not know what actions are and are not dangerous, adults make informed and intelligent decisions about personal safety (many make different conclusions than I do, that’s their right).

An adult human cadaver head cut off around vertebra C3, with no hair, weighs somewhere between 4.5 and 5 kg. So a stock Trek bike helmet at 12.4 oz, including dried sweat, weighs about 7% the amount of a human head. Not a significant increase, especially considering the wide range of possible accidents.

Nothing I said above "fails to recognize that the dynamics of the human body are far different than that of a rigid body. "

My statement doesn’t imply 100% correlation, by saying “engineer” as opposed to “scientist”, I was stating explicitly that, in practical terms, taking into account the order of magnitude of the obstacles in a rider’s way, there is little or no difference in the COM or spatial footprint of the helmeted and unhelmeted rider (especially the non-full-face-mask helmet that I weighed).

Hmm, well I’m not witless, and would like to know if anyone else, of good taste or bad, was offended by my remarks.

The thing about these kind of examples is that they don’t acknowledge the consequences of not doing them.

ie with breathing, there is indeed a danger of swallowing a fly; but that danger is insignificant when compared with the certainty of death from not breathing.

Same with seat belts- there are scenarios in which wearing a seat belt could kill you (eg, car sets on fire and the belt mechanism locks), but, on balance, far more lives are seaved by belts than are taken.

Concerning laws governing what adults do where safety is concerned, I share your unease, but two things make me not want to automatically dismiss such laws-

  1. the number of logically dodgy arguments put forward against them (the ‘everything is dangerous…’ being a prime example.

  2. Consequences- seat belts again being an example, when belt wearing was a choice, may drivers (probably the majority) choose not to belt up; so many died unnecessarily in accidents. Now, in places where belt wearing is a legal requirement, most do belt up, and, as a result, have found that there’s nothing wrong with it; in fact, most drivers, on occasions where they may forget to belt up, will get a feeling of being very insecure.

Most important, since the law was brought in, may lives have been saved.

It can be argued that such laws do diminish personal choice, but my feeling is that the blanket ‘all such laws are wrong’ is not the way to go. I would argue that some such laws are justified, others aren’t- it’s a matter of finding a balance between personal choice, and the consequences of not having such laws.

There’s no greater restriction to ones ability to choose, than being dead :slight_smile:

I can’t buy that theory at all, if a helmet weighed 7 pounds it’d be a stronger theory. But wearing a helmet does not increase the mass of your head SIGNIFICANTLY, the weight of a bicycle helmet is a small fraction of the weight of your head.

Whether or not a law will protect me or not is not the point, there is a saying about giving up some personal freedom for any amount of security and, by letting the government dictate our actions, when it does not directly affect the safety of others, is letting the government remove the possibility of choice for the governments perception of safety. If you don’t think that the government would prohibit things like getting out of bed, getting into bed, taking a bath (Oh, my god, that’s dangerous!) and breathing to protect us from hazards that we, the innocent, uninformed public, don’t know about, then, I’m sorry, but you haven’t been watching. A high percentage of accidents happen in the home, therefore if there are no homes then the number of accidents will be reduced (this thought brought to you by govspeak). Remember, big government is where the backwards motorcycle was conceived as safer, it steered at the back and was driven in the front. They actually spent hundreds of thousands of our dollars to build it before they asked any motorcyclists what they thought. Think about driving your car backwards, turn, and putting on the brakes, can you say out of control at every stop and corner? Please, please, don’t try this; it’s just that the people who conceived the cycle didn’t. Big government is the only known life form that has many hands and no brains.

Helmet laws have been shown to be counterproductive – areas that have instituted helmet laws have had the effect of reducing the number of cyclists by as much as 60%, which means instead of extending lives by 19 years (by cycling without a helmet) in exchange for one year (by wearing a helmet), people choose to not cycle thereby losing the health benefits that would get them the 19 years. The government seems to feel that this is a good thing, that some people will die 19 years sooner. Even if you stipulate that if everyone wore helmets they’d get 20 years of longer, healthier lives instead of 19, but some choose not to cycle instead.

There is still some question of whether or not bicycle helmets are actually effective or not. Lawmakers don’t seem to realize that requiring helmet usage is not the same a deciding to wear one. Did you know that the research shows that wearing a helmet reduces injuries to areas not protected by the helmet by 75%? Would this figure be larger if broken down into choice vs. required? I think it would. If I decide to wear a helmet, it means that I have a mindset that leads me to make decisions that will reduce the chance of injury, if I’m required to wear a helmet I don’t necessarily have the same mindset. Given this, does requiring helmet usage actually do anything? Even for motorcycling there is some question; the most vaunted studies are questionable, the incidences of motorcycle deaths were already on a downward trend before the first helmet law in the country (USA) was passed and the trend actually flattened a bit for the year after the law was passed.

Do I not use safety belts or helmets? I’ve worn safety belts since the middle 1950s (long before they were standard in any car) and won’t ride 10 feet with out a helmet; I just don’t believe that LAWS requiring me to are appropriate or effective.

What you say makes sense. I personally have no opinion on bike helmet laws, as I don’t know what the consequences would be (ie would it save lives or have the opposite effect).

However I stand by my points on seat belt laws (and therefore continue to disagree on the blanket opinion of all govt laws concerning safety being bad). That’s because it’s clear that many lives have been saved by the legal requirement to wear belts.

It’s good that you would choose to belt up even if it wasn’t a legal requirement; however, many wouldn’t.

Here’s another positive aspect of laws (IMO)- many who don’t wear seat belts, cycle helmets, helmets for skateboarding etc; do so because of pressures such as fear of looking stupid, fear of being a minority, peer pressure.

All those are real and powerful pressures that, in their own way, inpinge on personal liberty as much as any law.

Laws that require everyone to use such safety precautions make fear of looking different/stupid invalid.

Of course you can’t buy it, it’s not for sale! Especially to someone who rides, erp, b*kes :o

Face it, most people’s neck muscles are pretty weak. Heck, a bad night’s sleep can leave one with cramped muscles for the day. Unless trained regularly, the only task these muscles are really accustomed to is holding the head upright.

Even helmetless, a bumpy ride leads to a bobbling head, which leads to stress on the neck muscles. Add 5 to 10% more mass to the top of the head (increasing both the rotational and translational inertia of the head) and one will end up with a sore neck sooner than later.

5 or 10% might not seem significant if we were talking about stress on a more developed part of the body (i.e. arms, legs), but the average human neck can’t do much work…

The muscles in your neck are some of the strongest in the human body b/c they do support the head all day long…even people who do not work out have to support their head. A cramped neck from an improper sleeping position has nothing to do with the strength of your neck muscles.

I have mountain biked obessively for 7 years and have mUni’ed for 2.5 years and always wear a helmet and have NEVER gotten a sore neck from riding on rough terrain. Helmet weight is insignificant.

Can’t agree with you, the human neck is nothing but muscle, EVEN ON PEOPLE WHO DO NOT WORK OUT.

In addition to Zod’s commments, I would think that bouncing around with a little extra weight on your head several times a week will just make the neck muscles stronger in the same way that doing any kind of physical work regulary causes the involved muscles to respond by increasing in size and strength.