How to solve helmet hot spot problem

Discussion in 'Equipment' started by S21FOLGORE, Sep 7, 2018.

  1. S21FOLGORE

    S21FOLGORE Been here awhile

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    This was originally written for Ducati Monster Forum.
    It (the style) may not fit well into ADV rider forum crowd, but the info is probably useful for those who have dreaded hot spot problem.

    ========================================================
    How to solve the helmet hot spot (pressure point) problem

    Some people are lucky.
    “Helmet? Just about any manufacturer’s size M would fit me fine.”
    I’ve heard (read) comment like that.
    If you are one of those people, consider yourself being lucky.
    I’m writing this for those who are feeling like 
“It’s virtually impossible to find the helmet that won’t give me a painful hot spot. Pretty much every helmet I have tried starts hurting after an hour or so ...”

    I started wearing motorcycle helmet in the early 80s, and yes, in the past, I had always had hot spot problem, until I found out what was causing it.
    Seriously, ill fitting helmet can make you feel like you are wearing medieval torture device.
    Isn’t it nice if you can wear helmet for long hours continuously, without feeling pain, yet it (the helmet) doesn’t slip around on your head every time you do the head check?

    [​IMG]


    Know your head size and shape(not just “round, intermediate, long oval ...”)

    “If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in every battle.”
    ― Sun Tzu(544BC - 496BC) , The Art of War


    So, following one of the greatest strategist and philosopher, we are going to figure out about ourselves (our own head) and, ...
    the enemy... the helmet hot spot (what it really is, and how it happens).

    The very first thing you need to do is to know your own head size and shape, before start looking at bunch of helmet reviews at Revzilla and Webbikeworld.

    When you look at the user review of the helmet on the net, some people say Helmet XXX runs small and some say opposite, some say helmet ZZZ is narrow and some say it’s round. This happens because a lot (if not all) of them actually don’t know the “real” shape of their head.
    Majority of the people just “think” they have intermediate oval / neutral shape head.
    The word “intermediate” , “neutral” is a very slippery word.
    Some are roundish, some are more oval-ish, some have bump, some have large flat area (usually forehead or the back of the head), all these small things can cause painful hot spot.

    Now, rather than writing down the long and tedious generic theories about helmet fitting, I will use my own head as an example, to demonstrate how to get rid of the painful hot spot.
    That way, you probably understand better “how to” solve the problem.


    Taking measurement

    So, take a tape measure, and measure your head circumference size, like a picture below.
    But, everyone knows this already, right?
    [​IMG]

    Note.
    It is better to have someone to take a measurement, than trying to do by yourself.

    Take a few measurement, and use the largest one.

    Next, take a measurement of your head, front to back, side to side, using something like this
    [​IMG]

    That's called sculpture’s caliper. You can find them at your local art supply store.

    (In case you can't find it locally, here's where you can buy this thing.
    https://www.sculpturehouse.com/p-21-sculptors-aluminum-caliper-12.aspx)

    Alternatively, you can use the closet door (sliding door). Lay down on the floor, place your head between the door and the frame.
    (If you do this, be careful when to do it. Try not to be witnessed by your wife/husband, girlfriend/boyfriend. They may start worrying about you.)

    Next, run your finger tips on your head, to see if there’s any irregular bumps, large flat area, corners, etc.
    This step is very important.
    In my own case, this is the main reason of having the hot spot even though I’m wearing the correct size, correct shaped helmet.


    Head shape

    These days, most everyone who sells the helmets knows that they come in different internal shapes.
    (If they don’t know, or seems like they are not willing to spend some time with you, don’t buy from them.)

    I assume, if you are reading this, you already did the homework and know about the basics,(long oval, intermediate oval, round, etc, etc), so I believe you are not trying to squeeze your long oval shaped head into the round helmet (or, the other way around.)
    Thus, I’m not going to talk about those basic mistakes.
    And, if you have the helmet with wrong internal shape, nothing really helps. You have to start with the helmet that has , at least, the internal shape that is close to your head.

    One thing I would like to talk about the head / helmet internal shape, is that the vagueness of the term, such as 
“long oval”, “intermediate”, etc.

    Take a look at the picture below.

    fig.1
    [​IMG]

    What people call “long oval head” is either “long elliptical” or “long sub-elliptical” head.

    What referred as “intermediate” “neutral” is anywhere in between “elliptical” and “short-sub-elliptical”.

    What called “round” is,... well, “spherical”.


    Now, take a look at the measurement we took.


    My own head measurements are

    Circumference 56.5 cm
    Width (Side to side) 17 cm
    Length(Frond to back) 19 cm

    Width (side-side) : length (front-back) ratio is 0.89 : 1. (I will talk about this later.)
    Side to side measurement is about 10% shorter than front to back measurement.

    Judging from these numbers,my head shape seems like so called “round-oval”.

    The catch is, it is NOT.

    What these numbers don't tell you is that my head is pretty narrow at front(S size), the back side is a lot wider(M size or between M and L).
    On top of that, my head has pointy corners at the top/back.

    And that’s why lid-picker or helmet fitment data base on the internet (such as webbikeworld) never helped me.

    Take a look at the picture below.

    fig.2
    [​IMG]
    fig.3
    [​IMG]


    SO, my head at crown area (section X-X) is a “short, short sub-elliptical” head.
    Widest part of the head is closer to the back of the head, rather than in the middle (around the ears, temple area), front half is smaller than the rear half, narrow at forehead area, wider at the back.

    However, at section Y-Y, near the top of my head, it ends with square-ish corners at each side.

    Looking at from the back (section Z-Z), it looks like I have square shaped head at the top.

    (Note: Keep in mind, the shape in the drawing is exaggerated so that you can see it clearly.)


    So, these pointy corners at the back of my head start hurting after an hour or so, because some of the weight of the helmet is on these two “points”, rather than evenly spread over the large surface area.

    And, if I go up one size larger helmet, wrongly thinking that the pain comes from “too tight” fitting helmet, things get worse.
    Because with the loose fitting, the crown area can no longer support the weight of the helmet, and all of the weight will be on three points, on top of the head and two corners at the end.

    fig.4
    [​IMG]

    As you can see, too small helmet would be pinching the side of my head, and it becomes a torture device after an hour or so.
    (And if I get stuck in the heavy traffic, it really is a torture.)

    Unfortunately, there aren’t many helmets with egg shaped (narrow at front, wide at the back) internal.
    Even if I wear right size, typical “round-oval” helmet still gives me hot spot after 45min to 1 hour.

    The solution is NOT to compress EPS liner with spoon, golf ball, or baseball bat, like some people do.
    You need to change the thickness of the comfort liner padding.

    fig. 5
    [​IMG]


    ... the end of part 1
    to be continued
    #1
  2. S21FOLGORE

    S21FOLGORE Been here awhile

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    Changing the thickness of the crown pad
    Okay. Let’s take a look at fig. 5 in the last post again.

    [​IMG]

    In order to reduce the pressure on those corners on the back / top of my head,
    one thing I can do is to add more thickness to the back pad.
    As you can see in the picture, this will move the head forward inside of the helmet.
    Thus, creating more room at the back.

    Most of the time, this is the first thing I would try.
    (On my X-14 JDM (photo shown at the top of this thread, the one with fire unicorn on the side), replacing the back pad to thicker one, side pads to thinner ones are all I needed to get the correct fit.
    Goes to show how important it is to start with the “right” internal shaped helmet. Also, I should note that, as of this writing, X-14’s liner system is one of the best design out there as far as adjustability (for fine tuning the fit) is concerned.
    ※ I will explain more about this later.)

    Raising the helmet position

    Another thing I can do is to raise the helmet, a little bit.
    (and / or tilt the helmet forward / backward)

    fig.6
    [​IMG]


    With Arai helmet, this is very easy to do.
    Pull out the comfort liner, and adjust this tub.

    photo.1 Helmet sits lowest with this setting
    [​IMG]

    photo.2 Helmet sits highest with this setting
    [​IMG]

    Sometimes, raising the helmet position, or tweaking the tilt is all you need to get rid of the hot spot.
    ※ I will explain how to add foam to the comfort liner, etc , later




    Now, does your hot spot problem sound like this?

    1.The hot spot you feel pain / pressure is above your crown area.
    eg: at the top end of forehead, around hair line (or slightly above hair line)

    2.The helmet feels nice and comfy, snug but not too tight, in the beginning of the ride.
    But, at around 45 min. to 1 HR. mark, the pain starts kicking in, and it rapidly gets worse.


    fig. 7
    [​IMG]

    Her skull shape is lightly drawn with blue pencil.
    Blue pencil hatching area is where your head support the helmet most.
    Do you have hot spot on cross hatched with red pencil area ?


    Then, the cause of the hot spot is more of a “weight distribution”, rather than “tight fitting”.

    Next time when you are out riding, and start feeling the pain, try this.

    fig. 8
    [​IMG]


    Hold the bottom edge of the helmet, push it upward.
    If you feel the pain / pressure momentarily going away, then, you know it’s the “weight” that’s causing the pain.

    “Slightly loose” fitting helmet, “not enough support around the cheek” helmet, “close but slightly off” internal shaped helmet,
    can all cause this. Often, the front part sliding down as you keep riding.

    ...end of part 2
    to be continued
    #2
  3. S21FOLGORE

    S21FOLGORE Been here awhile

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    Let’s check out one more thing while we are talking about the helmet position on your head.

    Go for a ride, after 45 minutes - 1 hour, look into the mirror.

    How much space do you see between the eyebrow and eye port edge?

    fig.9

    [​IMG]

    When the helmet is worn properly, with modern day full face helmet, typically you should see about two-finger space between your eyebrow and the edge of the eye port.

    If you look like fig.9 - A, chances are ...

    You may be wearing too large helmet.

    Your helmet may be slightly loose, or the fit is slightly off, it slips down on your forehead as you riding.

    You may simply be wearing the helmet in a wrong way.


    The thing is, it is possible that, even though the helmet is the right shape and the size, it can still sits too low on your head. (Depending on your skull structure and the helmet internal shape.)

    To do the experiment (of the helmet height adjustment) is easy.
    You can use just about any piece of foam that’s about the same size as your helmet’s center pad, with the thickness about 5 - 10 mm (it is not so important at this stage).
    Or, if you don’t have a piece of foam handy, you can even use folded bandana for the experiment.

    Once you know raising the helmet position makes difference, you can add some foam to the center pad.



    This is how "SHOEI's personal fitting service" is done. (Sadly, this service is only available in Japan, and some euro countries. Not yet available in US.)

    Take the measurement of your head, front to back, side to side, and circumference

    [​IMG]

    Add some form, to where you need,

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    Can you see where the extra foam is added?

    [​IMG]

    [​IMG]

    You get the idea how to work on the comfort liner?

    You will need to add some foam around the hot spot (but NOT on the spot) to reduce the pressure to that point, (so that the pressure would be spread evenly, all across the head), NOT to depress the EPS liner in the hot spot area , or cutting off the foam(to make the foam padding thinner in the hot spot area), which, will make the matter worse.

    You can find foam at local craft store, hardware store.
    But if you want something more professional like result, buy open cell foam from the company like this.
    That way, you can choose the foam with the thickness and the density you want.
    https://www.foambymail.com/open-cell-foam.html


    [​IMG]
    [​IMG]

    As for adhesive, I recommend 3M super 77. (Available at your local art store, or industrial plastic store. It is also available from the link above.)
    https://www.foambymail.com/3M/3m-super-77-spray-adhesive.html

    [​IMG]

    BUT, don't use the glue until you are completely satisfied with the result.
    Carry a small piece of foam and small leatherman with scissors and go for a test ride.
    As you start feeling pain (or noticeable pressure point), stop, take off the helmet, cut the foam, add or subtract the thickness, and get back on riding. If you need, use (non permanent) double sided adhesive tape to hold the extra foam in place.

    Repeat the test ride - fine tune with foam until you are satisfied.

    ... end of part 3
    To be continued
    #3
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  4. S21FOLGORE

    S21FOLGORE Been here awhile

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    How to check and adjust the fitment

    So, how do you check the fitment?

    Maybe you have tried the helmet at the store for 15 - 20 minutes before purchasing it, to make sure it won’t be too loose or too tight, yet, that helmet still gives you dreaded hot spot after an hour. You are now not so sure about the fitment.

    Maybe you are in the market of the new helmet. You have narrowed down to two models, but can’t tell which one fits better. Trying them back and forth just confuses you more...

    Or, you are in between the sizes. ( I am.) You tired both sizes, and still can’t decide which one to get.





    In those situations, the simplest and the most effective way to figure out the fitting is,
    to remove the cheek pads then try the helmet.

    This will allow you to focus more on the crown area fitment.

    The feeling of the cheek pads pressing against your face can give you the false sense of tight fitting helmet.
    (Especially if you have ... err ... ample flesh on lower half your face...)

    Fig. 10

    [​IMG]


    Pay attention to the feeling around the crown area, and how the helmet is sitting on your head (height and angle).

    If it’s sitting too low, and / or, if you feel the EPS linger pressed against your head above crown line, place something like folded bandana between the center pad and your head.
    If it’s tilted down, place it slightly forward.

    Check if it makes any difference.

    Gently turn your head left - right, tilt up and down.

    How does it feel, in the area cross hatched with red pencil, in the fig. 11?


    Fig. 11

    [​IMG]

    Ideally, you should feel the red cross hatching area is "holding" your head with even, light pressure, rather than the helmet is clamping your head by a couple of "points".
    With cheek pads removed, you shouldn’t feel any pressure point. (Because, the helmet is literally just sitting on your head, like crown.)
    If you think you are feeling uneven pressure on your crown pad area with the cheek pads removed, you most probably need some adjustment.

    (Before we go into how to add extra foam to the crown / center pad, just make sure you are not wearing too tight helmet.
    Helmet is NOT a fashion item. I know a lot of people say, “ I don’t want to look like bobble head figure.” But, if you are thinking smaller helmet shell makes you look good, think again.
    Watch the movie clip below. 0:45 - 0:54.



    That’s Vincent D’Onofrio wearing AGV AX-8 Evo, in “CHiPs 2017 movie. And, look how big his face look like.
    If you wear too small helmet, when you open the face shield, your face look awful and small shell makes your face much bigger than it actually is.)

    Okay, let’s get back to the subject.

    (to be continued.)
    #4
  5. S21FOLGORE

    S21FOLGORE Been here awhile

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    This video shows (a little bit) about Arai’s fitting service.
    Basically the same job as SHOEI’s Personal Fitting System.

    The sponge work starts from 1:38.





    Adding foam to the top and the back

    [​IMG]

    Left is original, adding extra layer of foam to the right side

    [​IMG]
    [​IMG]


    Arai RX-7-X comfort liner (stock), comes with two-layer removable sponge at the temple area.

    [​IMG][​IMG]




    SHOEI X-14 with added foam on top

    [​IMG][

    Well, I’m in the middle of moving. (Which means, I have to pack up my drafting table, scanner and everything ...)
    It will take a little while till I can post next one.

    To be continued ...
    #5
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  6. Chaostrophy

    Chaostrophy Been here awhile

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    This looks super good, I'm very happy with the fit of my Arai Signet X, but I think I'll look at some tweaks.

    Sent from my Nexus 6P using Tapatalk
    #6
  7. S21FOLGORE

    S21FOLGORE Been here awhile

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    The example

    Dish washing sponge
    [​IMG]


    Cut into half
    [​IMG]


    Place on top of the head (between the center pad and EPS liner
    [​IMG]


    But, that’s going to block air flow (of the top vent system). so ...

    punch some holes through the sponge ...

    [​IMG]

    [​IMG]


    Done

    [​IMG]

    That’s good for the experiment, or temporally fix.
    That sponge on top of your head may be good enough to be permanent fix in some cases.

    If you need more fine tuning, here’s the basic guidelines. (what shape of foam, what density (hardness), where to put the foam)

    [​IMG]



    Adjust the top (helmet height) first.
    Then, side (temple area),
    forehead last.

    If you want just a little bit less pressure in the certain area, instead of buying multiple different thickness and density foam,
    you can punch hole(s) through the first layer of the sponge pad.
    Punching holes makes the same effect as lowering the density (perforated area springs back less than solid part.)

    You can find a punch set at your local craft store.
    https://www.joann.com/realeather-mini-punch-set/10208106.html

    (in my sketch, I drew a single big hole, which you can cut out with craft knife or sissors. But you may get better result with multiple small holes. It all depends on “how big the area you want to reduce the pressure”, “how tight the space is”,”how much pressure you want to reduce”, etc.)
    #7
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  8. rider1150gsadv

    rider1150gsadv Long timer

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    Great info! :thumbup
    #8
  9. TomServo

    TomServo Been here awhile

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    This is awesome. I posted up a link from my website, motorcyclewords.com, that points here. Great job and I love the illustrations.
    #9
  10. S21FOLGORE

    S21FOLGORE Been here awhile

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    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
    [​IMG]

    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
    [​IMG]

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

    fig.15

    [​IMG]

    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

    [​IMG]

    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
    [​IMG]




    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.
    #10
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  11. Pressingonward

    Pressingonward Looking forward to what is ahead

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    Most excellent! I scoured the web a couple years ago looking for in-depth helmet fitting advice and didn't find much. This is exactly the kind of detail I was hoping to find. Thank you!
    #11
  12. GS2Trout

    GS2Trout Adventurer

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    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
    #12
  13. eakins

    eakins Butler Maps

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    Locate the spot in the helmet. Use the back of a spoon and work the styrofoam in to fit better.
    #13
  14. 9Realms

    9Realms Drawn in by the complex plot

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    Someone's pretty handy with a pencil and paper. Compliments to the artist, well done.

    I can't even draw stick people :(
    #14
  15. S21FOLGORE

    S21FOLGORE Been here awhile

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    I will.
    I was in the middle of the moving (major pain in the b&%t), so I had to stop for a while.

    It is interesting that you brought up your "round head" problem (pain in the temple area).
    Because that's exactly I was going to do next.

    I am going to explain about it (I have rounder head, too).
    I think I can post the next part by Wednesday or Thursday.
    #15
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  16. Kayakgk

    Kayakgk Long timer

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    If there was a award for useful threads this would win one.
    #16
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  17. S/W

    S/W Been here awhile

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    I solved my "hot spot" problem by getting a BELL "Custom Fit" helmet. They laser scan your head and make the helmet for you. It will fit perfectly!! First helmet I have owned since the sixties that fit correctly. The helmet is approved by Snell.
    #17
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  18. FMFDOC

    FMFDOC IBA #63181 Super Supporter

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    How much might a fella expect to pay for that little service and where might one have to go to do such?

    Asking for a friend...
    #18
  19. Chaostrophy

    Chaostrophy Been here awhile

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    A search says $650 for the helmet, and $450 for the customization. Easy to find in a search, but they seem to have a traveling scanning service, you need to email to find out details.

    Sent from my Nexus 6P using Tapatalk
    #19
  20. FMFDOC

    FMFDOC IBA #63181 Super Supporter

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    Thank you.
    My Google-full is weak that late at night.


    edit: So I called and said, "I have a funny shaped head and have great difficulty finding a helmet that fits properly. I don't care what it costs; I will go to the place where I can get one made. Where do I need to go and who takes the money? I'll take one."
    They stopped doing that 2 years ago. :baldy
    #20
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