A comprehensive guide to HELMET FITMENT

[moto-rama]

I have been wearing mostly Shoei "Large" helmets for the past 25 years or so. They always fit perfectly.

I think Shoei has maintained a fairly consistent shape and size across their entire line of helmets for generations. That means I can order a helmet from them and be reasonably assured of a decent-fitting, and comfortable helmet.
I appreciate that consistency. It has saved me a lot of grief.

I have had a few other helmets and the sizing and shape varies widely from one to another. The Arai Quantum (Large) is also a good fit for me. But I have noticed a bit of difference in the fit of the Quantum line, not much, but noticeable.

Thanks for the writeup!

 

[Enchanter]

Pro Tip:
Helmet manufacturers want to market to people of all head shapes and sell helmets with multiple head shapes. Not all Arai’s are oval or round (head shapes). Same goes for Shoei, Bell, etc. Different models within a brand are shaped differently.

 

[fortyonethirty]

Wow, thanks for all the info.

 

[S21FOLGORE]

Thanks guys.
Here's the latest part.

Forehead pain explained

...and how to fix it

Let’s take a look at the two different shape of head.
They are, basically, both fall into the “long-oval” head category

Say, the size of these two heads are identical, front-back measurement are the same.
They both wear Arai Signet-X, in size M.

fig.13

After one hour of ride, despite the fact that both heads have the same front - back measurement and wearing the same helmet in the same size, one complains that his forehead hurts while the other is perfectly happy.
why and how did this happen?

Well, ...

Look at the size difference of cross hatching area (with red pencil) in the fig.13.

With the “narrow, pointy forehead” shape, the pressure on forehead area goes on very small area.
That hurts, after an hour or so.

With the “oval track shaped head”, the pressure is nicely spread across the larger surface area.


fig. 14

If you have protruded forehead, you may also have forehead pain problem.

fig.15

When people have forehead pain, even with “supposed to be long - oval shaped helmet” (such as Arai Signet),
they simply think
“This helmet is not “long - oval” enough, too round for my head”.
“My head is probably too long for this helmet”
“Maybe the helmet is too small”

While in fact they are wearing the right size and right shaped (long - oval) helmet.
It’s just that, anything that’s pointy, protruding, WILL cause the pain, after some time.

(That said, the entire helmet industry is moving away from making extreme long - oval or real round shaped helmet.
Will talk more about it later.)


So, what can you do to solve this problem, then?

fig.16

Option #1(left picture)

Using the leather punch, make some holes on the comfort liner front pad area.

Option #2(right picture)

Add some foam, like shown in the picture.

You can do both.

Basically, this is what you are trying to do.

fig.17

Next, I was originally going to explain about “pain on the temple area problem (round head rider’s problem)”.
but, there’s one more thing I need to explain before that.

 

[DucatiHoney]

Stickied.

As such, I'll ask that comments be kept on topic.

Thanks!

 

[S21FOLGORE]

Anatomy Lesson

Head shape classification

Anatomical terms for the three types of the head shapes (that we know as, Long oval, intermediate, and round)

Dolichocephalic (long head : what we call “long oval” head)

Brachycephalic (short head : what we call “ round head”)

Mesocephalic (intermediate)

The head shapes are classified by

Cephalic Index = x/y × 100
(CI = (bipareital diameter or BPD, side to side measurement) / (occipitofrontal diameter or OFD, front to back measurement) ) × 100

FIg.18
Click on the picture to see larger image

Hot spot 18, on Flickr

CI < 75 (female) 75.9 (male) is Dolichocephalic
CI 75 to 83 (female) , 76 to 81 (male) is Mesocephalic
CI > 83 (female), 81.1 (male) is Brachycephalic

Note : There’s a difference between male and female skull. That's why the numbers are different for male and female.

What matters for helmet fitment are




Smooth, more vertical frontal bone (forehead) on female skull

Male skull has more angled (tilted back) forehead

Rounded chin (female skull) vs Square chin (Male skull)

The more blocky and massive cranial mass on male skull vs rounder and tapering at the top female skull

Male skull have a deeper cranial structure

(I should probably explain the difference between caucasoid vs mongoloid skull shape difference, but let me keep on explaining about round head hot spot problem (pain on temple area) for now.)

(There’s also CRANIAL INDEX, which is essentially the same thing except for the fact that it uses the measurement taken from the skull.
For the people who deal with live human’s head (such as helmet manufacturers), Cephalic Index (which takes flesh and skin in account) is the one that matters.
For the people who deal with the skull (such as forensic artist), Cranial Index (which takes shrinkage of the dried bone in account) is the one to use.)

Now, this Cephalic Index would have been really useful if the helmet manufacturers had used this, to indicate the internal shape of their helmets.


Helmet for the round head

For example, Arai Quantum-X, supposed to be the most “round head friendly” helmet in U.S. market, would only work on the head with CI around 80 to 85.
I can tell, because my own head’s CI is 89, which is almost extreme end of Brachycephalic head, and Quantum-X is nowhere near as round head friendly as RX-7 -X (which is the JDM version of Corsair -X.)
If your head’s CI is greater than 85, even with Quantum-X (which Arai calls “round oval” helmet), you need to go one size up.

Instead of just saying “round-oval”, if Arai had said “Quantum-X ; round-oval shape, fits Cephalic Index 80 to 85”, it would have been much clearer. (Of course, they need to educate their potential customers, by explaining what Ci is. But, this will greatly reduce the hassle of buying a new helmet.)

AGV AX-8 Evo has egg shaped internal, and runs a little bit on the large side. But they have a lot thicker, plush crown pad in there.
The result is the helmet that works for the wide range of the head shape. (AGV GP-Tech was such a helmet also.)
I would say it (AX-8 Evo) works on the head with CI 75 to 85, even up to 90 so long as your forehead isn’t really wide.
(If you have wide, flat forehead and the CI is around 88 or over, it wouldn’t work.)



But, the hard, cold fact remains.
The true round head helmet is virtually non existent in today’s North American market.
NON of the helmet that are officially sold in US are designed for the head with CI greater than 85.

So, .... is there any option, other than going one size up, for the people who’s head CI more than 85?





Yes, there is.
Well, .... sort of.



... to be continued.

 

[Guoseph]

But, the hard, cold fact remains.
The true round head helmet is virtually non existent in today’s North American market.
NON of the helmet that are officially sold in US are designed for the head with CI greater than 85.

So, .... is there any option, other than going one size up, for the people who’s head CI more than 85?





Yes, there is.
Well, .... sort of.



... to be continued.

Eagerly anticipating this, last time I measured my head it was 6 7/8” x 7 1/8 which would give me a CI of 95. I wear a Japanese market Arai Cross Tour 3 and US market XD 4 with the optional side foam removed and have to make sure I cut my hair short on the sides. Everything else on the market is “intermediate oval” which for me equals “does not fit”

 

[S21FOLGORE]

Firs, let me show you this rather interesting data.


Brand∙∙∙∙∙Model∙∙∙∙∙∙∙∙∙Market∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙internal width / internal length × 100

Arai ∙∙∙∙∙Rapide SR ∙∙∙∙∙∙Japan ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙86

SHOEI ∙∙∙X-14 ∙∙∙∙∙∙∙∙∙∙ Japan ∙∙∙∙∙∙∙∙∙∙∙∙∙∙stock 86 / with thinner side pads, thicker back pad 93

AGV ∙∙∙∙GP Tech ∙∙∙∙∙∙∙∙∙US∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙96

Schuberth∙∙C3 Pro ∙∙∙∙∙∙∙∙∙US∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 80

Arai∙∙∙∙∙∙RX-7-X ∙∙∙∙∙∙∙∙Japan∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙86

Arai ∙∙∙∙∙Quantum-X ∙∙∙∙∙∙∙US ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙84

Suomy ∙∙∙SR Sport ∙∙∙∙∙∙∙∙∙US∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙78

Arai ∙∙∙∙∙RX-Q ∙∙∙∙∙∙∙∙∙∙∙∙US∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙77

AGV ∙∙∙∙AX-8 Evo ∙∙∙∙∙∙∙∙∙∙US ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙94


Some of them are now getting pretty old.
However, you can see, Arai & SHOEI ‘s JDM helmets are designed and built for the CI 85+ type of head, and it hasn’t changed over time.

IF you know your CI, and it happens to be greater than 85, you will get a better, a lot better fit from JDM helmet.
(Most probably, you have been wearing one size bigger helmet, or suffering the painful hot spot. For example, I can wear helmet with width / length ratio 78 helmet, but it will hurt after an hour or so.)


Some interesting stuff you can learn from this info

RX-Q wasn’t really that “round, as some people believed.

C3Pro, while it is definitely not a long-oval helmet, it isn’t really round helmet either.
(It’s just that they tend to run small, which means they are too short front - back for the size.)

Arai’s JDM full face has the most consistent width / length ratio over the decade (always around 85, 86).
With their center pad (crown pad) design, which has two layers of removable foam on the side,
You can change it to close to 90. (around 88, 89. If you still need more room at the side of the head after removing these peel-away sponge, you can use “leather punch” technique I described earlier. )

You can also change the center pad to thicker or thinner one.

SHOEI X-14 has the best liner system as far as the adjustability (for the different head shape) is concerned.
You can adjust it from 80 to 96. AND it’s very easy to do.

Very interestingly, AGV occasionally produce the helmet that works for the round head.
(But, the majority of their line up is not for the round head.)



So, the decision is up to you.

Anything you can try locally, it WON’T fit if your CI is more than 85. (Unless you go one size up.)
Anything you can buy from Revzilla / STG (so that you can return them easily) WON’T fit, either.

You know the helmets for the CI>85 head is available, but it has to come from the other side of pacific ocean.
There’s no way you can try them on before purchasing,
Even though you can return the item , exchange for different size / model, you want to avoid that.

What to do?

Sending a detailed e-mail to the customer service of online vendor in Japan, telling them your CI and asking if this ZZZ helmet you’re interested would fit on your head will not help.
You only get reply that says to look at the manufacturer’s sizing chart.


.... to be continued ....

 

[S21FOLGORE]

CI for the AGV AX-8 Evo is 94? That's surprising, since the online reviews (Revzilla, for instance) call that helmet "Intermediate Oval".

Seems like it's really round for that number. Do they then use padding in it to make it IO? I was considering trying one, but not if it's that round.

EDIT: Whoops, look like you explained that in the post further up. I might try that one anyway, as I do have kind of an egg shaped head, just with a slightly wider forehead.

About AGV AX-8 Evo

You can kinda tell, by looking at it from the bottom. (Actually, you can tell quite a bit by looking at the internal, once you study and learn about the helmet construction.)

AX-8 Evo (Naked)

From left to right, C3 Pro, RX-7-X, GP Tech

Why AX-8 Evo works on “intermediate oval” head, despite the really round (or, should I say, “short sub elliptical (egg, or pear shaped) internal.




#1 look at the cut out of eye port. How much of his forehead is exposed?

It’s cut higher, much higher than most of the full face helmet.

Incidentally, the same story applies to GP tech.

Can you tell ?


With these helmet, the part of your forehead that typically gets hot spot does not come in contact with the helmet liner !





#2 Incredibly thick comfort liner padding

Well, I have to take the helmet out and measure, to give you the precise number, but it’s around full 1 inch thick on these AGV, as opposed to Arai / SHOEI’s 7- 9 mm.

Wearing these AGVs is kinda like this.

You don’t feel the EPS liner at all, because of the padding being so thick and puffy.


Wearing RX-7, X-14 is like this.

You (somewhat) feel the EPS liner, because of thin padding. Therefore, right shape, right fitting is way more critical on these helmet.


#3 About Revzilla’s review
Not trying to be a dick, but, Revzilla’s “round - long oval” rating is based on the customers feedback.
And almost all these customers never measured their head (which means they don’t know their true head shape).
So, they aren’t that accurate to begin with.

S21,

Please continue with explaining this, as it describes PRECISELY what I am encountering. I have tried many helmets, and I get a piercing pain in my right temple after about 1 to 1 1/2 hours. My head is, according to lidpicker.com, very round ( 19.68 cm length, 17.46 cm width, and 61.28 cm circ.).

Thanks so damn much for all of your research.

Bill

Please be patient, I will write about the "pain on one side of the head (AKA asymmetrical head syndrome)", soon.

Eagerly anticipating this, last time I measured my head it was 6 7/8” x 7 1/8 which would give me a CI of 95. I wear a Japanese market Arai Cross Tour 3 and US market XD 4 with the optional side foam removed and have to make sure I cut my hair short on the sides. Everything else on the market is “intermediate oval” which for me equals “does not fit”

It sounds like you have very similar problem to mine. (Except for that your head CI is slightly greater than mine.)
Please be patient. I started explaining where / how to get round head helmet, and will continue.

The CI is cool, but it took me several attempts with my head half way into a closet door to land at 75 - confirming my long oval.

I enjoyed my two Schuberths, R1 and SR1 Pro, but their new range are no longer long oval = unhappy with my S2 Sport. Could have enjoyed the Euro version of Signet (Quantum ST Pro), but it's discontinued. (EDIT: was out in 2017, seems to be back now) Curious about the Nexx XR2, but the company is struggling I think. BELL Star maybe... USA brands (Icon +?) without ECE certification (problematic here). Well, enough about me, other than to explain why I'm motivated to UNDERSTAND the situation.

There is no way that customers can do this as part of a normal buying procedure. Clumsy and too difficult to get accurate measurements. Dealers would have to do it for us. Yes, a few of us (less than 5%?) are troubled (=motivated) enough to understand and then solve the problems. Not enough to make us worthy of the extra effort. Dealers would like very much to NOT have to measure heads and spend time educating customers.

I have heard complaints, not many, but a few, and not one single time was it followed by a serious question about why, how or what can be done? Most riders endure their headache, hot spots, fatigue or whatever. I have even offered to test/analyze and custom fit their helmet, for free, but no, not interested. 'Been riding 30 years with more or less problem and pain, might as well continue....' It's how we are...

Thanks for the feedback.

On the surface, With CI=75 head, you have opposite problem from mine , but essentially they are the same problem at the root.
Yes, the helmet manufacturers and the shop (authorized helmet dealers) really need to do more.

 

[budman]

- Well done!

 

[Reli]

fig.1

Thank you for all this, I haven't read of all it yet, but what perspective are these diagrams taken from? From above the head, looking down at it?
If so, then it looks like 3 of them are basically the same thing. A forehead that's more narrow than the back of the head. Is it just a subjective difference, or are there actual numbers to differentiate them?

 

[S21FOLGORE]

Yes, it is the shape of the head when you look from above.

Yes, the difference is totally subjective (especially the difference between short-oval and short-sub eliptical.)

Still, it is worth mentioning all these shapes for the purpose of this thread.

Now ...


Some important tips about “how to choose size” when purchasing helmet from overseas. (Meaning, you can’t “test fit” the helmet before placing an order.

The untold story of fitment, shell size and liner thickness.

(I’m going to use round heads (CI ≧ 85) as an example here. But, what I’ll explain applies to all type of head / helmet internal shape.)

Example story



So, you are in between the sizes, S and M.
You have been advised by people on the internet forums and by people at the local shop.
“Go for a smaller size, because the helmet (internal) will break in / stretch / mold onto your head.”

You believed that advice and purchased size Small instead of Medium.

You go for a ride happily with a brand new helmet ...

[url=https://flic.kr/p/2cebRM7]

... and an hour later, you get unbearable pain on the side of your head ...

[url=https://flic.kr/p/29C2KfG]

Sounds familiar?

If you have been riding many years already, tried more than a few different helmets and still get the hot spot on the same area, then you are either ...


wearing the wrong shaped helmet

wearing the wrong sized helmet

... or, could be doing both ...


You came across this thread, and measured your head’s front-back, side to side, and it turned out that you have CI 88 head.

So, now you know you have two problems.

The first problem is CI.
The helmets that you can buy locally, or from Revzilla, STG, etc, are all designed for the CI<85 head.

Knowing that JDM Arai / SHOEI are CI 85-86 helmet as a standard (can be tuned for higher CI), you decided to give it a shot.

But now, you are facing the second problem.

You are in between S and M size.

Which one should you order?

For obvious reason, you don’t want to end up ordering the wrong size and shipping it back to Japan, reordering the different size.

How do you decide the size when actually trying it on is not an option?

4-shell size vs 2-shell size helmet

Would you be surprised if I tell you that, with some helmet, the fitting is quite different from size to size?

???

Let’s take a look at two examples.

SHOEI X-14 VS OGK Kabuto RT-33

X-14 4-shell size




RT-33 2-shell size


First, let’s take a look at X-14.
They come in 4 different shell sizes.
S(S and XS use the same shell), M, L, and XL (XL and XXL use the same shell).

fig.19

[url=https://flic.kr/p/2cjjSYQ]

The relationship between the shell, EPS liner, comfort liner, and the available inner space of the helmet is the same all across the sizes, except for XXL.

Except for XXL, all the helmet comes with 9mm thickness comfort liner as a standard, and you have options to go either thicker (+4mm) to make the fit tighter, or thinner (-4mm) to make the fit looser.

Each size of the helmet (except for XXL) has the same amount of tolerance / limitation for irregular bumps and slightly oversized head.

To put it simple, M is the scaled down copy of L, and S is the scaled down copy of M, they all have the same amount of space for fine tuning.



Now, RT-33, which comes in 2-shell size.

It uses the same shell for XS, S, and M. And L, XL, XXL share the same, bigger sized shell.

Now, look at the picture below, pay particular attention to the liner thickness and the helmet labeled size.

fig.20

[url=https://flic.kr/p/29Cb3bu]


Yes, you guessed it right.

Size XS, S, and M are THE SAME HELMET with different thickness comfort liner installed.
And size L, XL, XXL are the same helmet, the difference is just the comfort liner thickness.

With this type of helmet, it is a little bit tricky to choose the size.

If you happen to be between the S and M size, you should order S, NOT M.

You have 15mm thick foam surrounding your head, that’s a lot of cushioning, and it will tolerate the slightly oversized head (56.5 cm) without problem, even if your head has some irregular bumps, bulges, etc.

BUT, if you are in between M and L, then, you’d better get L.

“Why? I don’t want a bigger shell size ! You just said “L” size helmet use the same shell as XL an XXL, that would make me looking like a bobble-head figure!!”

Well, I (sort of) understand the feeling, but take a look at the fig.20 again.

RT-33 in size M comes with the 2nd thinnest (9mm) comfort liner. (thinnest being 5mm on XXL).

Size M comes with the least amount of tolerance(extra space), besides XXL, for irregular shapes and oversized head.

If your CI is 88 for example, and circumference is 58.5 cm, I can almost guarantee you that you are going to get painful hot spot on the side of your head if you wear size M.

IF. your head shape is slightly off (eg: CI 87, 88) BUT the correct size (between 57 and 58 cm), then M will work.

Or, if the head shape is correct (CI 85, 86) but circumference is slightly greater (58.5 cm), them M will work also.

However, when both the shape and the size are off at the same time, you can’t go for smaller size.

So, I hope you now understand the “multiple shell size” is NOT for the looks, but for function.

Also, I hope you understand now, that why some helmets cost more than the others.
(Just making 4 different sized molds for shell, and 5 different mold for EPS liner would easily make X-14’s production cost more than twice the production cost of RT-33.)



Oh, by the way, the same rule applies for multiple shell sized helmet, when it comes to sizing.

If you happen to be in between the sizes, you can go for a smaller one
ONLY IF your CI is close enough(±1) to the helmet’s target CI.

Otherwise, you’d better order the larger size.




One method that works (for only Arai and SHOEI) for size checking is to use genuine issue boonie hat.
Go to the military surplus store and try them on.



The brand doesn’t matter, as long as it’s made to proper specification which is MIL-H-44105B.

For example, the size 7 is 55.9 cm. If the size 7 feels too tight, but next size which is 7-1/4 (57.8 cm) fits alright, you should get M, instead S.
If 7-1/2 is too tight, you should get XL, not L.

You know, boonie hat does not stretch, so you should be able to tell clearly if it’s too tight.

 

[lam@barf]

and I will be posting links to your thread all over other moto forums.


.

 

[Reli]

Y

Would bang


Seriously though, thanks for the great work!

 

[mosquito]

Thanks for sharing this! Great descriptions AND illustrations!

FWIW, I think it could also be printed up and sold.

 

[S21FOLGORE]

SHOEI X-14

One last thing I may add.

Why SHOEI X-14 is so great, in terms of adjustability?

Because it offers more range of adjustment for many different types of the head shape.

You may have forgotten, but my head (looking from the back) has two corners at the top
(almost like I have horns on the back of my head.)

Well, the hair is deceiving. It covers the corners, the irregular bumps on the head.



(It also (kind of) acts as buffer zone, between your helmet and skull.)

It looks goofy, but this is how the center pad sits on your head.



If you are having hot spot problem and trying to fix it, then, you really need to take off the liner and wear it,
look into the mirror, figure out which part is pressing hard on your head.

This is the most important for my particular head.
See the gap between the top pad and the side pad (where I am pointing)?



This is how mine is set up.



See the huge gap there? That’s where my horns go through.



Now, if I close that gap there, like this ...


... then, it will give me some very annoying pressure point ...



... even though it is exactly the same helmet with the same liner ...

If you ever decide to try X-14, don’t disregard it just because it doesn’t fit exactly right
when you first try at the shop (or purchasing from online store.)

Pull out the center pad (which is very easy) and try closing / enlarging the gap between each pads.

You can also do it on the road side if you want to experiment.




Snap off one side at the back...



Snap off the other side ...



Pull the front portion out from the eye port opening ...



... can you see better?



Then, just pull out the entire center pad



No need to mess around with cheek pads or chin strap.
This is one of the best design out there.

 

[Butch]

very interesting read. subscribing to find it later.

That. You deliver. I've seen those head caliper things before.

 

[S21FOLGORE]

About "replacing helmet after 5 years" thing

So, you have the helmet that you can happily wear for hours without pain, but doesn't slip around on your head.

Do you have to replace it after 5 years, as some people say?

I was kinda hesitant to post this, (because this may "open up the whole can of worms"), and it's not directly related to hot spot/ fitting problem.
,but, in the end, decided to post against my better judgment. (I originaly wrote this for ADV rider’s thread, regarding the helmet’s “sell by date”.)

First of all, I want all of you to understand that this is what SHOEI North Amarica, who is a distributor, NOT the actual helmet manufacturer, says.
(Yes, yes, I understand that for us who live in US and Canada, SHOEI North America IS SHOEI (since SHOEI Helmet in Japan won't directly communicate / do business with us), but still, you have to understand that what they(SHOEI North America) say is NOT exactly the same as
what SHOEI Helmet in Japan (as a manufacturer) says.


Now ,...

Let's get clear about the fact that SHOEI North America NEVER said the helmet is not safe to use after 5 years from the date of manufacture.
What they say, is

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

(exempt from here

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:
1. The helmet was subjected to an impact.
2. The comfort padding or the retention system has become loose due to heavy use or display signs of deterioration. Test: with the retention system fastened, the helmet turns to the side when you gently shake your head.
3. The EPS liner has come away from the helmet shell.
4. The EPS liner shows signs of wear and is beginning to break up, or if it has been exposed to heat or a solvent and has melted. There are indentations in the EPS liner and/or white scratches can be seen on surfaces with black paint.
5. Even if none of these is applied, we, SHOEI, recommend replacement in 5 years after it's first purchased at retail.  )

The "5-year" time frame is NOT based on the research (of how much deterioration happens over the years).
It is decided that way for the sake of convenience (5-year limited time warranty).
(Arai North America, Schuberth North America, they all do the same. 5-year limited time warranty, recommending the helmet replacement after 5 years of use.)

You know what Arai and SHOEI (and OGK) say, in Japanese domestic market?

Let's take a look at the manuals of JDM version.

Arai

SHOEI

Yes, I know you can't read them.
But, you can see "SG" (ＳＧマーク= SG mark = SG sticker) in both Arai and SHOEI's manuals.
You can also see "3" in SHOEI's manual.
(In Arai Manual, it is writeen in Kanji character,  "三" (means 3)).

What they are telling you is that they recommend to replace the helmet
AFTER 3 YEARS from the date of purchase.




Yes, 3 years.

They are telling their customers in Japan to replace their X-14 after 3 years from the date of purchase.

WHY?

Because of these.

Close Up

Can you see this ?

This is the sort of "insurance" system they have in Japan that expires after 3 years from the date of purchase.

These things have "SG sticker" ...

These things (folding walking cane) have SG sticker ...

They (the manufacturers of motorcycle helmet, boys baseball helmet, walking canes ) have to pay fairly huge amount of money and get their products certified. Otherwise, the products cannot be sold as "motorcycle helmets" or "baseball helmets" or "walking cane".
(Without certification and SG sticker, these things can be sold only as "for decoration", it's illegal to sell them as motorcycle helmet / baseball helmet / cane / cooking pot / whatever ....)

So, they tell their customers (in Japan) that they recommend to replace the helmet after 3 years, based on this system.
Not because the helmet gets deteriorated and becomes unsafe after 3 years.



As far as I could remember, this (3-year time frame for recommending helmet replacement) has not changed from all the way back to the early 1980s (when I started wearing motorcycle helmet).

So, the helmet manufacturers NEVER said the helmet is unsafe to use after 5 years from the date of manufacture.
The distributors (SHOEI North America, Arai North America, Schuberth North America, etc etc) NEVER said that either.

 

[Butch]

Great post. I love Capitalism.

 

[S21FOLGORE]

Just a heads-up.

You can no longer buy Arai and SHOEI helmets from oversea vendors.
(They may still sell other brands, buy won't sell Arai and SHOEI (and their genuine accessories / parts) to US customers.)

More details in here.
https://www.bayarearidersforum.com/forums/showthread.php?t=544509