How to solve helmet hot spot problem

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

  1. nxcong.x14

    nxcong.x14 Adventurer

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    Thank for sharing....
    #61
  2. workerB

    workerB Adventurer

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    Helpful thread, thank you S21 and others for your info! I'm a motorcycle noob, just got my Icon Airmada from a local shop summer 2019. The salesman and I thought I had a somewhat oval shaped head. I'd read Wes Siler strongly recommending Ece rated helmet, icon was. Salesman strongly recommended tight fitting size Medium, said it would relax, breakin after use. That didn't happen for me. I just recently figured out I could order thinner cheek pads, considering that as current ones squish my cheeks a lot.

    But, first, I wanted to figure out my hotspot, middle of my forehead. My head circumference is 22 3/4 inches, about 58 cm. Using this thread, I figured my ci to be .81 ratio, which S21 labels as mesocephalic intermediate, not oval like Revzilla says the Icon is.

    I m trying to make this helmet work if safely possible. I tried extra padding on top of my head. Separately, I tried 3 different thicknesses of additional padding to the left and right of my forehead center. Still had hotspot. Put aside all extra padding. Tried markk53's sanding idea, sanding away estimate of 1/16 to 1/8 inch thickness from eps from the center forehead 4 inch area of the helmet. Still had center forehead hotspot. Most recently, sanded total of 1/4 inch from the center of the above center forehead section, about 1 inch wide side to side by 1.5 inches high. First ride, about 40 minutes, seems like this helped. I want to try a longer ride to be sure.
    #62
  3. workerB

    workerB Adventurer

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    20200409_125644.jpg
    Here is picture of inside of my helmet after sanding.
    #63
  4. workerB

    workerB Adventurer

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    It seems like I have a forehead that protrudes a lot. However, I said all the above to explain this question. If the 1/4 inch I've sanded out works for my hotspot, does that much sanded off the eps make my helmet much less safe in case of impact? I absolutely appreciate any feedback you all may give me. Trying to think if I should invest in thinner cheekpads to make this helmet more comfy, or look to a different helmet altogether to better address my hotspot.
    #64
  5. S21FOLGORE

    S21FOLGORE Been here awhile

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    If you have read this thread, you know now that both Arai & SHOEI offer fitting service in Japan.
    They also do custom fitting for racers.

    Do they modify EPS liner to do the fitting service?
    NEVER.
    Even back in the 1980s, they didn't do that.


    Also, EVERY SINGLE helmet manufacturer tells you
    NOT to modify shell & EPS liner.

    Why?
    Well, you have draw your own conclusion.

    Some say removing / compressing small amount of EPS liner has no negative impact on the helmet's safety,
    DESPITE the warning from ALL helmet manufactures.

    Some say it is okay to shoot +P+ ammo in J-frame.
    Would you?

    Be very careful when you read something on the internet.
    #65
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  6. markk53

    markk53 jack of all trades... Super Supporter

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    Sanding will take off probably less than 1/8 inch of material and if you figure it proportionally based on the material crushing that would knock off probably less than 10%, depending on the thickness of the EPS. So yes it may lose a bit of capability in that one spot, but it would be well worth it for the reduction in distraction of the hot spot. It is also better than crushing the material.

    So what are the odds of hitting that spot in a crash? Find one of those diagrams and some crashed helmet images and you will see the odds of hitting that slightly reduced area of the helmet is extremely low. Low enough that it doesn't rate having a specific zone marking with a percentage. Seems most are some variation of the chin and the sides not showing an area of direct front or rear. So sanding that 1/8" out seems to be a good choice when compared to the distraction of the hot spot.
    #66
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  7. workerB

    workerB Adventurer

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    S21FOLGORE, thank you for this thread and the further feedback. Markk53 thank you as well for your feedback.
    #67
  8. markk53

    markk53 jack of all trades... Super Supporter

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    Most hot spots in the best fitting helmets don't take much sanding to get comfort. I maybe took off 1/16" in a very small area to get the fit right.
    #68
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  9. Pressingonward

    Pressingonward Looking forward to what is ahead

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    If you truly sanded 1/4" off of a ~1" thick liner, you have FAR less protection in that specific area.

    I personally would not do that, but I do see what others are saying about the odds of hitting that spot in a crash, and the value of a comfortable helmet. My recommendation would be to buy a new helmet that fits if you can afford to do so.
    #69
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  10. markk53

    markk53 jack of all trades... Super Supporter

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    I know I am not talking about sanding a major area down to resize a helmet. I am talking about the quarter to half dollar size spot that makes a small hot spot.

    An area the size of a half dollar. Far less safe? I think not. Personally I've done that, then oddly enough crashed with that helmet. Went high side slammed face down onto a hard pack gravel road. No problems other than a scuffed up helmet. Head was fine.

    Now if you think that is so dangerous how do you justify those air flow grooved liners many manufacturers are using? They cut a heck of a lot more material out than my little spot sanding yet they seem to still be safe. Then, worse yet, they stick in those internal flip down mini tint shields. How is my recommended sanding anywhere near as bad at that?
    #70
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  11. lacofdfireman

    lacofdfireman Long timer Supporter

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    I know there was a link for some foam padding to buy but has anyone found or sourced foam locally anywhere? Anyone used anything that’s more common to find than buying online?
    #71
  12. S21FOLGORE

    S21FOLGORE Been here awhile

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    CI 81 is NOT long oval head, at all.
    A friend of mine who's Scandinavian (Norway) has CI 75 head, which is definitely long oval.

    If your helmet / head shape are way off, and/or the size is wrong, you really can't make it work.
    If you have to modify EPS liner, you are better off buying a new helmet that fits your head properly.

    I am not going to engage in "if it's okay to sand down / compress EPS liner" discussion.
    And I won't tell you what you should do and what you shouldn't. You decide it by yourself.

    But, I will tell you one interesting story.
    Back in the early 80s, none of the full face road helmet had "vent".
    In 1983 or 84, SHOEI came up with the idea of putting two inlet vent holes on the forehead, two exhaust vent holes on the back.
    [​IMG]

    You can see two black oval thing on the forehead. (Vent holes.)

    Then, Arai helmet officially announced that drilling the holes on the forehead is going to reduce the helmet's ability to handle the impact,
    they will NEVER, EVER drill holes on the forehead.
    That's how they came up with "brow vent shutter" system.

    [​IMG]

    After some 35 years or so, they still refuse to have holes on the forehead of their helmets ....

    Arai also use "one piece, multiple density" EPS liner.
    Which means, their EPS liner's density is different depending on the portion.
    The reason behind is ...
    (Okay, I have to get back to work now. I will write later.)
    #72
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  13. S21FOLGORE

    S21FOLGORE Been here awhile

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    ... so, Arai helmet refuse to drill vent holes on the forehead portion of the helmet.

    Their reasoning for this is,
    #1: The probability of you getting involved in crash and hitting forehead may be less than hitting other part of the head,
    BUT IT'S NOT ZERO.
    It can happen.

    #2: The helmet's forehead part is more difficult to design. Because it has to handle the impact with smaller surface area.
    That's why they change density of the EPS liner depending on the position.

    Some helmet use multi-piece EPS liner, in order to change density.
    Some helmet's EPS liner has different thickness for different part of the helmet.



    I have read people saying, "Why Arai doesn't make drop down visor helmet?", " I wish Arai would make modular (flip-up front) helmet "
    ...

    Well, ... it's not going to happen.
    That "brow vent shutter" story is only a small part of the story.

    Arai helmet is, very, very unique, because the company is not driven by marketing.
    The company is driven by one man's passion and opinion (which is, very strong, and quite often, biased.
    This company can exist only in Japan (probably).


    When BMW system helmet came out, Arai announced that they are not going to make flip-front helmet, because they don't believe having hinged chin bar is safe enough.
    (Well, the truth is, CEO, Michio Arai, doesn't like the idea of having hinge on chin bar. And his "like / dislike" is all that matters.
    He doesn't care what market wants. He doesn't care what is "trendy".

    The same story goes with drop down visor.
    Arai is not going to make it. Because drop down visor system requires to make cavity space in the forehead area of the helmet.
    And Michio doesn't like it.
    For the same reason they don't drill holes on forehead.


    That's how they came up with "Pro Shade" system.

    [​IMG]





    BTW, after having used Schuberth C3 Pro, I got to the conclusion that flip-up chin bar and drop down visor are both "fashion / trend" thing.
    So I went back to RX-7-X. (Then, X-14.)
    I don't need modular, I don't need drop down visor.

    Of all the helmet that I have owned / used in the last 37, 38 years (or so) was ...

    [​IMG]

    Arai Rapide SR (from around 2005, this was JDM only model) size;S, fitment on my head was spot on, shell size was like 20%smaller than current helmets (well, maybe not by 20%, but helmet shell was noticeably smaller back then.)

    X-14 is close second. (After swapping pads on the side and back, the fit is excellent.)
    #73
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  14. markk53

    markk53 jack of all trades... Super Supporter

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    I don't believe Shoei was first in the crown venting (above the face shield), based on personal experience. I was selling bikes in a Honda dealership in the 80s and the first vented helmet that we could get our hands on was a Marushin. A Japanese helmet company. I know. I was specifically looking for a cooler vented helmet and the first that showed up was the Marushin. Most only had maybe a chin vent, if that. I had been watching the developments and looking at the big dealer trade show that was in Cincinnati back then.

    The other interesting thing was the development of an air conditioned helmet, but it never panned out, I think AGV bought the rights, but it never went far. Apparently the weight and the fragile circuitry were the problems.

    The Tucker Rocky rep, who sold us Shoei helmets came in with a Marushin one day. I asked to take a ride wearing it. The venting worked great, centered just above the eye port clearing the top of the shield with good flow, especially for the times. It was impressive, I bought one shortly after that. I don't remember when the Shoei helmets with vents showed up. I know when they did, the owner of the shop bought one. He had a Shoei head shape. I didn't as I later learned. I wore Bell helmets until the Marushin, then AGV after that.

    So in our market the first vented helmet that showed up was the Marushin. They stopped importing a few years later, apparently they could not break into the market here in the U.S. It was a great helmet, I had two of them. It was a bit later that Shoei helmets with vents in them were available - at least that were available to us. I don't remember when Arai came up with their shield venting.
    #74
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  15. DareYou

    DareYou n00b

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    Does anyone know what the CI for Scorpion ADX-1/AT950 is? I have a circumference of 56,5cm and CI of 86. When trying a medium, I immediately get two strong pressure points on top of my head (probably horns too). I'm thinking of getting one, but I'm not sure if I'll be able to make it fit, trying all the tips and tricks in this awesome thread. Thank you for the info.
    #75
  16. workerB

    workerB Adventurer

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    I found a sponge under kitchen sink, sliced in half with bread knife for use in top of helmet, for height adjustment. Had some foam from previous craft project leftover for forehead hotspot fine tuning. Got from Wally world and Crafts store 2000 20200421_090312.jpg 20200421_090249.jpg 20200421_090220.jpg
    #76
  17. S21FOLGORE

    S21FOLGORE Been here awhile

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    #77
  18. spuh

    spuh Been here awhile

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    I don't need modular, I don't need drop down visor.

    Of all the helmet that I have owned / used in the last 37, 38 years (or so) was ...

    [​IMG]

    Arai Rapide SR (from around 2005, this was JDM only model) size;S, fitment on my head was spot on, shell size was like 20%smaller than current helmets (well, maybe not by 20%, but helmet shell was noticeably smaller back then.)

    X-14 is close second. (After swapping pads on the side and back, the fit is excellent.)[/QUOTE]

    All this worrying about holes at the forehead and space for a sun visor and you go and plop your helmet on the mirror?!! Apologies if your favourite helmet is not actually perched on the mirror; what IS holding it on the bike?
    #78
  19. lacofdfireman

    lacofdfireman Long timer Supporter

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    #79
  20. S21FOLGORE

    S21FOLGORE Been here awhile

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    [​IMG]

    My beloved Valentine One, put gloves on top of V-1, then ...

    [​IMG]

    [​IMG]


    I normally don't put helmet here. These photos were taken for explanation purpose of
    "How I hide my V-1 when getting pulled over by LEO".

    99% of the time, people automatically assume the helmet is on the mirror, even though there's tiny CRG lane splitting mirror on the left bar end.
    #80