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Discussion Starter #1 (Edited)
I have just read,with interest, a discussion on a motorcycle helmet's useful life on the Other Classifieds section.

I'd like to open the discussion here.

I am one of the "every 5 years" guys based on the information I have been able to read...until the recent thread.

Please express your intelligent opinion here:smoking:

(Bonus points if you can explain, in simple terms, the title of this thread.)
 

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Heisenberg and Schrödinger get pulled over for speeding.
The cop asks Heisenberg "Do you know how fast you were going?"
Heisenberg replies, "No, but we know exactly where we are!"
The officer looks at him confused and says "you were going 108 miles per hour!"
Heisenberg throws his arms up and cries, "Great! Now we're lost!"
The officer looks over the car and asks Schrödinger if the two men have anything in the trunk.
"A cat," Schrödinger replies.
The cop opens the trunk and yells "Hey! This cat is dead."
Schrödinger angrily replies, "Well he is now."

I love that joke!
So if the helmet is in the box it is alive (good to use) until you open the dated box of course! :):):)
My oldest daughter is getting her doctorate in theoretical math!

Ed :)
 

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Discussion Starter #3
Love the joke, Ed. Good interpretation, but within the context of the conversation, it's not quite right.
(Good luck to your daughter!)
 

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Helmet Compass song.
 

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Well I gotta chime in, here is shoei's info right from their page:

"Helmet Replacement
Ultimately, the useful service life of a safety helmet is dependent on the intensity and frequency of its use. Helmet replacement is recommended even if only one of the under-mentioned points applies:

The helmet was subjected to an impact.
The comfort padding or the retention system has become loose due to heavy use or display signs of deterioration.

The synthetic foam padding displays signs of heavy use and the helmet feels too loose. Test: with the retention system fastened, the helmet turns to the side when you gently shake your head.
There are indentations in the EPS liner and/or white scratches can be seen on surfaces with black paint.

Even if none of these is applied, we, SHOEI, recommend replacement in 5 years after it's first purchased at retail."

As it states the 5 year period is after it has been purchased at retail. Its from the time you bought the helmet and started using it. It has nothing to do with useful life of materials or when it was manufactured. The other points are valid. If you were to purchase a helmet made in 2008 and it was brand new never used it would be perfectly fine.
 

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Discussion Starter #6
Arai has similar recommendations.

I know, from personal experience, that things made from foam degrade with exposure to use and some just simply degrade over time. Glues become brittle and no longer perform their function at some point.
 

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I do the 5 year or damage as referred to by shoei as I run their helmets.

As a mechanical engineer by trade and institution I had a few physics and theory classes so here goes.

Heisenberg had the uncertainty principle while Schrodinger concocted the physics contradicting common sense with his cat theory.

So although Heisenberg states he didn't know how fast they were going but knew exactly where they were meant that he couldn't possibly know how fast they were going due to his uncertainty principle stating you can't in fact know the location and speed of any given particle or item. After the cop tells him his exact speed Heisenberg is upset because knowing his speed means he couldn't be right about his location due to his own theory.

Schrodinger on the other hand knew the cat was simultaneously both alive and dead at the same time until the box it was in was opened. Implying that Schrodinger's cat paradox was taking place in the back of the car that Heisenberg was driving. As the officer opened the box there was a 50/50 chance that the cat would be dead or alive. In this instance the cat was dead which upset Schrodinger...obviously because his own cat is now dead due to the experiment.



The Schrödinger cat paradox (yes I decided to spell it right there) has gained quite a lot of popularity lately for one reason or another. For those that aren't familiar with it, it was a thought experiment against the Copenhagen interpretation on quantum mechanics and how they related to common things. So after saying that Schrodinger proposed that there is a box, in that box is a cat, a radioactive isotope, a Geiger counter, a jar of poison and a hammer. The box is rigged in a manner that if the Geiger counter detects radioactive decay that it will trigger the hammer to break the jar of poison this killing the cat.

On the quantum level there is a 50% chance of the isotope decaying and a 50% chance of it not decaying. This shows, that because you don't know if the isotope is decaying the cat In theory is both alive and dead at the same time in the box. The outcome of the cat isn't established until the box is opened. But that is where they differ the cat in theory can be both alive and dead at the same time but not in reality (where Schrodinger and Copenhagen differ) because when you look in the box you see the cat alive or dead not both.

So the challenge comes in at the point where quantum level physics ends and reality occurs.

Wow can't believe I just type all that out on my phone at lunch.
 

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Discussion Starter #8
So, 99, that being the crux of Schrodinger's Cat, how does it apply to the topic at hand....
 

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Thank you Jon-Michael!

I was not going to even try tp do something similar on my phone. Bravo!
I too replace my helmets on a regular basis, about 5 years or damage.
Arai too has the same recomendations as Shoei.
Is our question about the "life" of our helmets and or their component materials?, opinion and philosophical discussion asside, I happen to also be of the thought that materials do deteriorate over time.

In 1981 I had a pretty bad crash, hit the road at 75mph+, my 4 month old Bell Star saved me.
Sent the helmet to Bell, as requested by the warranty registration, Bell x-rayed and repaired the fiberglass (that was a heavy helmet!) REPLACED the foam liner and returned it.

Soooo...do our modern helmets/materials last longer? Plastics are similar to paint always "drying" until the bond is lost? We replace rotating components of aircraft turbines at thier "half life" to preclude any age related failure. I myself am going to stick with recomendations of the manufacturer. I know guys that use 10-15+ year old helmets...not for me. i want to see my daughters (yes 2 in grad school!:):)) get their doctorates and still enjoy art and physics/math jokes!

This could be interperted as you don't know if you will die (like the cat eh?) or be injured in an "old" helmet when you crash or "open the box"?
Of is it the half-life of the materials that could result in negative consequences.
At least with GPS you know where and how fast you are going! :):) When you crash?

Ed :)
 

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So, to bring the analogy into play here, it's basically that we won't know if a 5+ year old helmet is ok to use until someone actually tests its (in which case he may be brain dead of not, depending on whether the helmet is OK or not)......

What the other thread needs is some hard data showing whether or not an aged helmet retains sufficient protection for continued use. As noted in that thread, there are many factors that can affect the outcome, and no real definitive way of knowing exactly how or what has deteriorated. So, is the cat alive or dead? I wouldn't want to find out!
 

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Discussion Starter #11
So Gearhead gets the T-shirt.

You won't know a helmet is good or not until the moment it needs to be at its best:

When you crack your noggin against something the helmet was designed to protect you from.

Up until that point, the helmet is good, and the helmet is bad. Quantum Physics.
 

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Damn I got enveloped in the explanation and forgot the correlation lol.

Took me awhile to get back on here to see that been busting it in the yard getting some new plants in.

My view on it was the same. Although the helmet is both new and deteriorating at the time of purchase it fits Copenhagens interpretation since the manufacturer says it's 5 years from time of purchase although it could have been sitting on a shelf for a year ticking it's decaying clock.

As far as Ole Schrödy is concerned the moment of quantum superposition is realized at the moment you impact it and it either has a chance to fail or not (hopefully not).

I guess if Heisenberg were involved in the shindig he could say that if you were traveling at 180mph with said helmet and you crashed, you would most definitely not know your exact location...and probably be comatose.

:)
 

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The Schrödinger cat paradox (yes I decided to spell it right there) has gained quite a lot of popularity lately for one reason or another.
You can thank the TV show The Big Bang Theory for that one. Taking a group of impressionable young individuals and turning them into a swarm of pseudo-intellects who boast of their knowledge of the universe; yet can't use the correct their/there/they're to save their lives.

Thanks once again, TV.
 

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Discussion Starter #19
I'm too old to watch The Big Bang Theory. I do know of it, though.

I'm not a fan of absolutes...they never exist.:smoking:
 
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