Did you know that studies have shown that up to 25% of people are in the wrong size helmet? According to a video Jay Leno did with Arai that was released in 2013, that number is as high as 8 out of 10. Unfortunately, I can’t find properly cited concrete numbers, but based on the hundreds (if not 1000+ at this point) of helmet fitments I’ve done, it definitely seems to be more than half.
If I were to guess based on my experience, the main reasons for this are that 1) people tend to judge how tight a helmet is based on how difficult it is to get on instead of how it feels once it’s on, 2) they don’t account for the helmet breaking in, and/or 3) they choose the wrong shape helmet for their head, causing them to compensate with incorrect sizing.
Cheek pads break in and helmets get easier to take on and off over time. The polystyrene impact layer breaks in up top as well. There is really nothing that can be done about the wrong shell size or shape once you’ve chosen a helmet though.
Helmet brands vary pretty drastically in internal shapes. There are many cases where people bring a helmet to me that’s the right size, but it’s wrong shape for their head. This isn’t quite as bad as having a helmet 1–2 sizes too big, but it’s still not going to be nearly as effective as one that’s both the correct shape and size. In these cases, I have the person put the helmet on and physically show them why it isn’t the best fit for them.
One thing to remember is that aside from safety, the correct shape and size helmet is also usually the most comfortable helmet. They will move around the least and won’t cause headaches due to uncomfortable pressure points.
The helmet you should choose is the one that is best for you — not one that your friend recommends because they like it, or the one that’s blowing up in your newsfeed from retargeting ads. The helmet you should choose is the one that’s best for you. Period.
For now, I am only going to cover fitment and consequences of improper fitment here. Helmet quality and construction is an entirely different subject that we’ll save for another day.
Before we get into the smaller details, let’s start with a basic step-by-step helmet fitment guide:
1) First, grab the straps of the helmet you’re trying on and open them up like this to get your head inside it:
I can’t tell you how many people plop the helmet on top of their head and just pull or push it down by the outer shell. Don’t do this:
If you don’t pull the straps apart to open the helmet up, you’re going to be fighting the cheek pads. It’s going to feel way too hard to get on, which will deter you from choosing the correct size.
Do yourself a favor and pull those straps apart. It will help the cheek pads clear your ears and make entry much easier. Do the same when you’re taking the helmet off.
2) Once you have the helmet on, you want to see that the trim of the eye port is about 1.5–2 fingers’ width worth of space above your eye brow. If the helmet goes on too easy and ends up sitting right at the eyebrow, then the helmet is too big.
It’s rare that people will be drawn to a helmet that sits too high up because it’s usually way too tight if it does that. In other words, I wouldn’t worry too much about it sitting too high, but sitting too low is a quick giveaway that the helmet is the wrong one for you.
If you look at my Arai, Scorpion, and old Bell helmet, they all have a sufficient amount of room above my eyebrow:
There are a couple reasons I don’t use the Bell helmet anymore though. Even though it has proper spacing, it actually fails the…
3) Roll test. While the helmet is on, tilt your chin up slightly and push up on the back of the helmet with gradual increasing pressure. If the helmet is right for you, it should move your scalp and face skin then rebound back to its original position. My Arai XD4 and Scorpion VX-16 both pass this test very well:
What’s even more telling is that I don’t even have to pump up the air fit cheek pad system in the Scorpion, so it has a firm hold on my head solely based on how well it fits just the crown of my head.
If a helmet feels like it’s loose up top but it doesn’t move because of how tight the cheek pads are, that’s still incorrect. When I suspect this is the case with someone, I will usually add more upward pressure to the back of the helmet to discover that the helmet easily rotates down once friction has broken loose from the cheeks.
My Bell helmet is a perfect example of a helmet that looks okay at first but completely misses the mark. I bought it when I didn’t know any better, and look at this:
Good spacing above the brow, decent pressure on the cheek pads, and yet it moves way too much and fails to rebound back into place after a roll test. This indicates that it is the wrong shape helmet for my head. In the event of an impact, it could have come down and broken my nose or come off my head entirely given a strong enough hit.
What’s happening is that I put my long oval head in a shorter rounder helmet, resulting in this scenario if you were to look at the top of my head inside the helmet:
The front and back of my long oval head are holding it in place, but there’s not enough contact around the rest of the helmet.
Most people in the mid Atlantic region of the US have a similar shape as me, so I see this issue with Bell helmets so frequently that I rarely sell them. All of their MX-9s — both ADV and standard — as well as their lower end street helmets, like the Qualifier, share this shape. This doesn’t mean that they’re necessarily bad helmets. It just means that they’re bad helmets for a long oval shape. (Many Asians and Hispanics have much wider heads that actually fill in these helmets very well.)
People with round heads can often find themselves in the opposite situation where the head sits in an intermediate or long oval helmet like this:
Once again, this scenario will fail a roll test every time because there is not enough friction to hold it in place. The sides will basically act as pivot points while the front and back are just kind of floating out there.
4) Pressure on the cheeks. New cheek pads should lift the cheeks up a bit and feel like they’re making you bite your cheeks as you talk. These tend to break in quite a bit, so it should be pretty tight out of the box. As long as it passes the previous two checks (spacing above brow and roll test) and the helmet moves with you side to side without delay, then the helmet is likely a good fit for you.
5) Check how much space is between your mouth and chin bar. You should be able to push pretty hard on the chin bar and still not be able to reach it with your face. If you can stick your jaw out and touch the chin bar or push it into your face with moderate pressure, that helmet could knock your teeth out. You want enough space where the cheek pads and front of the impact liner on top would absorb an impact to the front — not your face.
As mentioned before, I have a long oval head. I can actually fit into a large Arai XD-4, but my face was too close to the chin bar. I experienced the same problem with the Scorpion XT9000 in size XL. I also tried an XL Klim Krios, but being an intermediate oval lid, it created the dreaded forehead hotspot and didn’t pass the roll test. The Shoei hornet sort of fit okay, but it still felt like I was between sizes.
As a solution, I went up to an XL in the XD-4, got the thicker interior liner (10mm) to fill in the top, and went up 3 sizes in cheek pads (from 15mm to 30mm) to fill in the space around my somewhat narrow jaw. Arai is the only brand I’m aware of that has enough customization options to do this much of a variance with the fitment. Each helmet has 3 interior sizes and 6–7 cheek pad sizes (ranging 12mm–40mm). This allows their helmets to fit the largest variety of head shapes and sizes without any compromise.
Arai also offers three different shaped helmets in their street line — Intermediate, round, and long oval. Their off-road line is a somewhere between intermediate and long oval, with customizations allowing you to capture all but the roundest of heads. From what I’ve heard, they alter it to fit differently in different countries though, so a VX-Pro4 from Europe may be a different story than one sitting on the shelf in the US.
One of the big reasons I’m a fan of Arai as a salesperson is because if a friend recommends Arai to someone, I rarely ever have to talk them out of one. I can almost always get a perfect fit with all the customization options they provide. It’s one less obstacle I have to overcome and the person is usually happier because they were able to go with their friend’s recommendation — win, win. (They’re also the safest helmets IMO, but that’s another story.)
With that being said, the Shoei X-Fifteen gets an honorable mention for being pretty much just as customizable as an Arai (though still lacking a variation of head shapes). Scorpion’s Airfit system is an innovative design for cheek pad adjustments too.
Now that you’ve gotten a general idea of how to fit a helmet, let’s discuss what can happen if you get this wrong. Once again, the diagrams below are very simplified and exaggerated for conceptual purposes, but the principles remain.
Starting with a long oval in a round helmet (like my head in a Bell MX-9), look what would have happened if I’d taken a hit on the front:
Pretty much all of the impact would go right into my forehead rather than dispersing around the entirety of my head. Now, if I’d taken a hit from the side:
It would have directed all the force to these two spots on the side of my head, possibly also squeezing my head. In an extreme case, the helmet could have flexed so much it caused a secondary impact to the side too.
Let’s talk about the other scenario now — round head in a more elongated helmet. An impact to the side would look like this:
Once again, basically direction all the force to one spot instead of spreading it out evenly. Not good. A frontal or rear impact could potentially be even worse because the helmet could shift and ricochet back at the rider’s head, amplifying the hit with a secondary impact as demonstrated below by the yellow arrows:
A rapid shift of the helmet with your head inside can be catastrophic. I am also convinced that in either incorrect shape scenario — if hit at just the right angle — the helmet could also cause a secondary twisting force where it shifts, picks up rotational velocity, and then “re-grabs” your head in a violent manner, potentially resulting in a neck injury. That would look something like this, with the red arrow representing the initial hit, the yellow oval and arrows representing how the helmet shifts, and the faded red lines representing where it catches:
This is actually why I’m not 100% sold on MIPS. I’m not against it and do believe it does more good than harm; however, I often wonder how much it’s just compensating for an improper fitment and lack of helmet education. It’s much easier to throw MIPS in a helmet and market that as your saving grace than it is to make several different helmets and try to educate an entire customer base on how to choose the best one. MIPS doesn’t do anything for blunt force impacts either.
Every MIPS helmet I’ve seen also has stylistic lines on the outside, which act as potential catch points that can cause rotational forces to occur. It kind of completely contradicts everything that MIPS represents.
If you’ve ever noticed Arai’s round egg shaped helmet shells, well… that’s by design. It’s so they can’t catch on anything in a slide or hit in any way that twists your neck. All of those aerodynamic flares and stylistic shapes on other brand helmets may look cool, but they are all potential rotational force hazards. (I know I know… said I wouldn’t discuss safety features here, but some was bound to pour out.)
Anyways, a proper fitting, correct shaped helmet should disperse impacts across the most surface area, making the helmet safer. I darkened the background and added a yellow glow to represent how force would distribute over a perfect fit below:
The more you spread out impacts over space or time, the better off you will be. Those are really your only two options for staying safe — either spread out changes in velocity over time or over space (surface area). If you’re using your helmet, then you’re probably out of time, so you better have something that disperses force over the largest amount of space possible. This is why I cannot emphasize fitment enough.
Lastly, lets go over the most common mistakes I see people make:
1) Choosing too big of a size because your face is wide. Just because you have a wide jaw does not mean you need a huge helmet. Please understand is that your head shape is separate from your jaw line. Cheek pads can often be swapped out to thinner ones in many cases, but it needs to fit you correctly up top.
2) Thinking your head is round because your face is rounder. Again, cheeks and jawlines have nothing to do with head shape. Look just above your ear — is the side of your head flatter or more curved?
3) Thinking your head is round because it’s wide. This is incorrect because it’s possible to have a wide head that’s also intermediate or even long oval in some cases. (Again, how flat or round is your head just above the ears?)
4) Dealing with pressure points on the forehead or sides because they don’t know better options for their head shape exist.
5) Being fixated on a particular brand because of their marketing or because all your friends are wearing them. Those pros are not you. Your friends are not you. Get what’s best for you.
For a general idea of how different helmets fit, check out my quick reference guide.
There will never be a substitute for having a trained professional fit you for a helmet in person. If you have the option, then go get fitted. I understand that not everyone has access to that where they live though and many shops lack the knowledge and/or resources to do so, so my hope is that this article can at least help you make a better decision for yourself. A better fitting helmet is always a safer helmet, so learn what you can and get the best lid you can afford. Action sports are awesome, but you have to be smart about your approach to them if you want to participate for a long time. Have fun and be safe!
