How to solve helmet hot spot problem

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

  1. Sepooli

    Sepooli Adventurer

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    Dude You are awesome.
    Sorry for my late reply, I thought I would get notifications if you post anything.
    I measured my own head by putting my head in between a sliding door.
    but I will also try to make the caliper you just posted for better measurementS for both the helmet and my head.
    So do you think I should return the hjc rpha 11 Carbon until I find a better fit helmet with your help? I dont have much more days for the return window. i really was hoping that I would keep it specially due to its weight being so light.
    my current helmet is shoei QWEST (i believe it is for round heads) and its not a good fit at all, i bought it 5 years ago when i did not have any knowledge of head shape. but I think i can live with it a bit longer until I find the right helmet, since having a comfortable helmet is my only reason for buying a new one.

    By the way I always wear a bandana before putting my helmet. So I will try to also measure my head with the bandana.

    i appreciate your help again.
  2. markk53

    markk53 jack of all trades... Super Supporter

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    Caliper measurement will get you in from the ball park to the infield. One problem - measuring the padding and matching it to your head will not give a good fit if you go size on size. The padding will seat in and the helmet will be loose. The caliper measure will give you the shape, but not the size. You can figure if you have an egg shaped head or round head, you can even figure the rough proportion of length to width. But it will not give the size needed. There needs to be firm pressure uniformly around your head. It should be firm as possible without causing a headache. Only way to get that fit without being stuck with a bad helmet is to try it out before going riding...

    To reach home in the game you need to do what I call The TV Test. You put on the helmet for an hour while watching TV or the like at home, so you don't get bug splatter all over a new helmet you may need to return. In this time the new helmet should feel tight, but uniformly snug all over the scalp. If it presses hard front to back or side to side you will feel it, the helmet shape isn't quite right. It will be obvious if the helmet is just plain too small. The helmet should be returned and a different size or style should be picked.

    Ask the retailer if you can return a helmet if it is a bad fit. Absolutely recommend you test a helmet at home before going riding, getting it sweaty inside and bug splattered. Make sure it is tolerable for an hour or so. That way if you have to return it, it's not trashed.

    With some helmets if you get a good fit front-back you can get different size cheek pads to make a better fit. Arai is one that is really adjustable in that way, going as far as having thin shims to fit behind pads. I think Shoei and Bell can be done too, not sure about HJC. Kind of fine tuning the fit. Many helmets with removeable liners can have cheek pad sizes changed out for the next smaller or bigger.

    Sometimes a helmet fit is near perfect but on spot maybe 1" diameter is the hot spot. Many hot spots are specific spots where you may have a small rise/bump on your head that presses harder against the helmet liner than surrounding area. The helmet may initially fit like a glove, but after 20 minutes to an hour you start feeling that one spot that is burning. That one spot causes the pressure between the skull and the helmet to pinch the skin there. From a bit of reading - the closing of capillaries in the skin are what causes the hot sensation.

    For example I had picked up a Shoei helmet (1988) and found it to be too round for my head, pinching between the front and back, while having way too much space in the sides. Had to return it for a more oval head fit. I picked up a Marushin (no longer in the US, was Snell rated) and it fit like a glove... except for that one spot I mention above. One small spot... sanded and fixed.

    That one small spot is where some will compress the EPS with a spoon or round object, personally I just took some coarse sand paper and sanded the spot, which was only about 1" diameter, removing maybe 1/16"-1/8" of EPS in that one small spot. The small bit of modification, especially sanding, will affect the safety of the helmet appreciably.

    I think times have changed and the padding in the new helmets is better quality than that of the 80s. Seems it holds up better, not breaking down to a loose fit. Even with the hot spot in the Marushin, eventually the padding broke down to become too loose of a fit. In the past years I've had a KBC, an AGV. a couple HJC, and a Joe Rocket. Padding in the newer helmets over the past several years has held up far better than the first Bell Star I had (1975), the next Bell Star (1982), and Marushin (1988).

    I think the better thicker padding avoids having the hot spots of old, I haven't had to modify a helmet to suit my fit for a couple decades. Plus even if the padding breaks down and the helmet loosens up, now I can buy a new liner kit.

    Do the calipers, figure your head shape, find the head shape of the helmets of interest, figure the size needed, do the test, get a good fit.
  3. S21FOLGORE

    S21FOLGORE Been here awhile

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    I suggest,

    #1
    making cardboard caliper, and measure your head again, then measure the internal of HJC RPHA 11.
    That way, you will have clear idea, if the the helmet's internal shape is "close enough" to your head shape.

    #2
    If it turns out that your head CI and helmet's target CI is way off, (for example, your head CI =77, helmet's target CI =80)
    then, you should know that the shape (of the helmet) is not right for your head.

    #3
    Whether to return it or not, ... I really can't tell you. You have to decide.
    BUT ... here are a couple of things that (probably / hopefully) help you to make decisions.

    overall situation about the helmet internal shape

    If your head CI is less than 80, or more than 86, chances are, there aren't many options.
    The majority of the helmet manufacturers are shifting to so called "intermediate" , " neutral" shape,
    and stopped making "long oval" and "round" shaped helmet.
    You may find some that are more compatible with your head, but they may not be the ones you like.
    (For example, ICON, LS2 make many models for long oval head, but you may not like them ...)
    So, first, understand and accept the situation.
    You don't have that much to choose from.

    size & CI

    Don't listen to the people who tell you
    "Always go for smaller size. They (helmet internal) will stretch / mold onto your head".

    That is based on the assumption of both the size and the shape are spot on.

    If you go one size down while the shape is off, you are going to have hot spot.


    To figure out if you can make it work, or to return it ...


    Take measurement of the helmet internal with and without center pad (crown pad),
    In other words, measure EPS liner's shape.

    Then, check out if HJC offers thinner / thicker option crown pad.

    Make some cardboard "thickness gauge".
    (Cut them down to 1" wide, 10 - 13" long)

    Remove the cheek pads from the helmet, and put it on.

    Try to stick the cardboard thickness gauges between your head and crown pad.
    You may be able to stick them from the bottom, you may have to do it from the eye port opening.

    How many cardboard thickness gauge you can slide in ?
    How freely they slide in?

    Look at the size chart again.

    You may be able to make it work with

    ... going one size up (and add foam to the side)

    ... going thinner crown pad (and add foam to the side)

    ... or do both. (But, check out how many shell sizes they make first.)
  4. S21FOLGORE

    S21FOLGORE Been here awhile

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    You can cut up some dish washing sponge or old T-shirt, stuff them in the bandana, instead of working on the helmet liner.
    That may be the easiest way to go.
  5. Sepooli

    Sepooli Adventurer

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    I think helmet liner would be easier and better for long term. I can manage that.
    thanks
  6. Sepooli

    Sepooli Adventurer

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    Thanks a lot for you reply both.

    i made the caliper you advised S21FOLGORE and measure everything again:

    my head:
    162/210 = 0.77

    helmet with padding:
    129/186 = 0.69

    helmet without crown padding:
    160/220=0.73

    The one I bought is the size xl and is the largest shell they have, they make 3 shell sizes for this one.
    But i believe the xxl size is also the same shel, but has thinner padding.


    Sorry i did not fully understand the cardboard gauge thing. I understand how to create it and how to test it.
    But i dont think even one gauge will slide in from the front or back with the padding on the helmet.
    So I should get the xxl and then do the gauge thing from the sides to add more paddings on the side?
    Thanks again.
  7. S21FOLGORE

    S21FOLGORE Been here awhile

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    No.
    If you can't slide a strip of cardboard, then, there's not huge gap on between your temple area and the helmet.
    Your helmet is close enough for your head shape and size, it seems.
    Judging from your measurement, I think, the helmet is "just a little bit" too short front to back, for your head.

    Check if they(HJC) offer thinner crown pad for RPHA 11.
    If they do, that 's where I would start.

    If they don't, get a punch set, and punch out some holes on the crown pad forehead area where you thing it's offending.
  8. S21FOLGORE

    S21FOLGORE Been here awhile

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    Almost forgot ...

    You can (should) also experiment with helmet (sitting) height.

    Go back to page 1, post #7 shows the photo of dish washing sponge on top of the helmet, to raise it a little bit.
  9. Sepooli

    Sepooli Adventurer

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    Thanks a lot S21FOLGORE

    I am planning to return this one and get the XXl size which has the same shell size but 3mm thinner liner. Then I will try to adjust it by adding foams as per your advise.
    I will post an update after.
  10. Sepooli

    Sepooli Adventurer

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    The picture below shows my helmet the size xl

    is the gap on the side normal? I could slide one piece of cardboard gauge to the side of my head? I assume it will be even more when i buy the size xxl.
    Is it okay when I go to xxl size and fill these sides with foam?

    Also another problem i found with the current size is that it really pushes hard on my cheeks and jaw.

    Attached Files:

  11. Sepooli

    Sepooli Adventurer

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    Do you think i should order arai signet-x and play around with it or the same helmet with thinner liner?
    Arai one is heavier and much more expensive.
  12. S21FOLGORE

    S21FOLGORE Been here awhile

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    Yes, it is normal.
    Some manufacturers intentionally make this "gap", so that people can slide eyeglasses easily.

    Cheek & jaw discomfort may be fixed with thinner cheek pads.
  13. S21FOLGORE

    S21FOLGORE Been here awhile

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    This, I really can't say which way you should go.
    Like, I cannot tell you which girl to go out with, which one to dump.

    When people decide to buy a helmet, there are some factors...

    such as...

    Budget limitation

    Personal preference (that includes, "brand" preference)

    When you have been riding 30 years, 40 years, your priority list changes.

    (At that point, you care more about proper fitment and comfort while you are actually riding with that helmet on, than "brand name preference (which is based on internet talk, not based on real life experience), graphics, "coolness" image you have about particular model / brand, etc, etc.)

    So, for example, my experience with Arai helmet goes back to early 80s. I have nearly 40 years of riding experience with Arai helmet.
    On the other hand, I have zero personal experience with HJC.

    If I were in your situation, I would try Signet -X first. BUT, it's based on my personal history stated above.

    Don't overly get caught on the "spec data" before you actually try something.
    (For example, the extra weight of Arai may look like a big deal on internet talk, but it may not be a problem at all when you actually wear it and ride.)
  14. Sepooli

    Sepooli Adventurer

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    Thanks a lot for your help again.

    I will update you with my results.
  15. Sepooli

    Sepooli Adventurer

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    so i ordered and tries one size larger the hjc rpha 11 XXL, but i think this one still needs modification.
    When you asked to try to put a sponge on top and try to raise the helmet, i think my problem is actually the other way around and the helmet does not fully come down on my head! Another interesting thing I found is that, this helmet actually kind of hurts my ears, and I believe it is because of the two parts on the side for clasping under the chin and also because the helmet is not coming does fully on my head. I felt like the Pockets for speakers do not match my ear position.

    so this helmet also left a red spot on my forehead shown in the picture and also had a big relief on my ears when i removed it after 40 minutes of wearing it at home.
    Also i think the back of my head is abit to big and that is why it puts pressure on the forehead . you can also see a picture of the side of my head attached.

    F7EFAC15-D20B-4672-A596-ED4EAEB67C9C.jpeg

    33E73FA6-6FBC-496C-B735-94B3F653EE49.jpeg
    i then tried a bit if modification like the drawing you showed earlier and wore the helmet for almost an hour. I folded and added paper towels on the 2 points shown in the picture below. The forehead problem i think was a bit better.
    B3854995-B5A4-4F74-BC6C-1B3EC0C9CA91.jpeg

    I will try to do a bit more modifications and will update it here. I think I will also buy the signet-x in size XL and see how that goes.
  16. RandomRider007

    RandomRider007 n00b

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    I have a question about putting holes in the forehead liner? What size holes should I use and where specifically should I make them in the forehead liner.

    I have a CI of 0.86 and bought a helmet from Japan and it fits well except for the fact I have a bulging forehead. Moreso, just the left side of be forehead (I seem to have a bump there).

    Do I make the holes right at the pressure point? My leather hole punch has 2mm, 2.5mm, 3mm, 3.5mm, 4mm, and 4.5mm. Which is the best to use?

    Edit: If it helps I have the RT-33 in small with the wide liner (21mm front to back and 9mm side to side)

    Would it be better to get the all round 9mm medium liner and add foam to the front and back?
  17. Sepooli

    Sepooli Adventurer

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    The purpose of creating the holes is to remove some volume.
    you can start by making some small ones and then try the helmet and add more holes if needed.
  18. Sepooli

    Sepooli Adventurer

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    I ended up buying the Arai Signet-x one size larger (XL) and it feels so much better already.
    I might have to do some slight modifications if it the liner starts to loosen up after wearing it for a while.