When out helmet shopping, there’s one question that always comes up: what’s the difference between polycarbonate, fiberglass, and carbon fiber helmets? Which is safest and which is the most comfortable?
Polycarbonate vs Fiberglass vs Carbon Fiber Shell Motorcycle Helmets
What shell material is the best or preferable in certain situations has always been an incredibly tough question to answer among motorcycle riders. All you need to do is see how many crash tests there are out on YouTube right now.
And though this is certainly the most important aspect of the best motorcycle helmet and we’ll touch on this, we also wanted to go a bit further to see if there’s any difference in riding comfort if we collect all our road test results.
Polycarbonate vs Fiberglass vs Carbon Fiber Safety
As far as safety goes, all 3 materials will be safe. A thermoplastic or polycarbonate motorcycle helmet-like, for example, the Shark Evo-One 2 can get to the 4-5 star range from SHARP just as well as any other fiberglass or carbon fiber motorcycle helmet. In this case, it got 4 stars, which is excellent.
The main difference for safety is the helmet’s weight and the material’s behavior in an impact. Polycarbonate is more susceptible to abrasion so you will need more of it to provide an adequate level of protection. So, as a result, you’ll end up with a heavier helmet.
But, the flip side of this is the helmet will absorb impacts across the outer shell better. So, polycarbonate performs better at lower speed impacts. Some examples of a polycarbonate helmet include the Shark Evo One 2, Nolan N87 Plus, or the HJC i90.
With fiberglass motorcycle helmets, you’re getting a stronger material that, alongside composites, will be a bit more flexible in its impact absorption. This is where you usually see most middle to high-end touring helmets with extra features like drop-down sun shields. Examples of fiberglass helmets include the Arai RX-7V, Schuberth C4 Pro, and Shoei X-Spirit 3. So, there is a real range of applications here.
As far as the material itself goes, fiberglass will be lighter than a polycarbonate helmet. But, since it is harder, it will absorb less energy across the shell. This means the helmet will need a bit more EPS to absorb this extra energy.
Lastly, we come to carbon fiber, which you generally see in any top-range helmet. For example, this is where you see helmets like the AGV Pista GP RR or the X-Lite X-803 RS Ultra Carbon. That’s because it is even stronger than fiberglass, which again means you get an even more lightweight helmet.
Thanks to its high rigidity, it is also going to perform very well in high-speed impacts, which is why it’s often used in high-speed racing helmets. But this does mean it won’t perform as well for lower speed impacts as a material like a polycarbonate.
Generally, this same order of polycarbonate, fiberglass, composite, and carbon fiber is the same for the safest shell materials if you look at SHARP. However, since helmet safety is much more complicated than a simple yes or no, the best thing to do in this case is to make sure you’re buying a quality helmet from the website bestmotorcycleriding.com, make sure it is ECE or DOT rated, and you can also check out SNELL and SHARP for a second opinion.
Also, look at what material is specifically used, since you have different levels within each shell material category. For example, the Lexan polycarbonate that Nolan uses in their helmets will do better than ordinary polycarbonate and so on.
How do different shell materials perform on the road?
We have received questions about the difference between the two shell materials in terms of how they do on the road and how well they stop the noise. We were curious too, so we went back to our road test results and crunched the numbers. Just as a reminder, we conducted all our tests on the same bike traveling at about 130 km/h (or about 80 mph) on the highway.
For our measurements, we used a decibel meter placed in the ear of the helmet, a thermometer placed in the EPS liner’s grooves, and an anemometer mounted on the bike for the day’s airspeed. We’ve taken our data from 49 helmet tests from brands including AGV, Arai, AGV, Schuberth, Shoei, Nolan, X-Lite, Shark, Airoh, and Schuberth. For the purpose of categorization, we included Shoei and Arai in our fiberglass category, but you can expect them to do better than ordinary fiberglass since they actually use composite material.
Shell Material Results
When we looked at all our helmets together, we were not particularly surprised with the results. Ultimately, polycarbonate came out as the worse for both weight and noise, since it earned 3 and 2.5 stars respectively. The interesting thing is that fiberglass and carbon fiber helmets actually earned the same 3 stars for noise, and there was a half-star difference for weight. So, that’s 4 stars for fiberglass and 4.5 for carbon fiber.
These results aren’t very surprising for a number of reasons. First, this is simply the nature of the helmets we were able to test. Most polycarbonate helmets are going to be more budget and will have less going into them in terms of comforts like weight and noise isolation than fiberglass or carbon fiber helmets.
You can see this reflected in the other categories like ventilation and comfort, which are also slightly lower. And, when you get up to this higher helmet range, so much goes into making these helmets quiet that you actually end up at about the same noise level.
For weight, the results also are what you’d expect polycarbonate is heavier than fiberglass and fiberglass is heavier than carbon fiber. The only thing to keep in mind with weight is that depending on the helmet you may also find that you experience a bit more buffeting with a lighter helmet.
Pros and Cons of Polycarbonate, Fiberglass, and Carbon Fiber Helmets
So, to summarize briefly, polycarbonate helmets will be more inexpensive since the manufacturing process is much simpler. As a result, you often get a good variety of graphics and the material itself is strong in low-speed impacts since it is less rigid and can disperse the energy across the shell.
The downside of polycarbonate will be its higher weight since you need more of the material. Since this is also the material of choice for budget helmets, this also usually means you’ll only get budget features. And, as a related point, it will also generally be a noisier helmet.
For fiberglass, the pros are that it is lighter than polycarbonate, and not as rigid as carbon fiber so it can still disperse some of the impacts, though not as well as polycarbonate. It will also be much less expensive than carbon fiber thanks to a less intensive manufacturing process.
The cons of fiberglass are that it is less rigid than carbon fiber and not as good at dispersing energy across the helmet shell. So, you need a bit more EPS to make up for it. Lastly, they’ll have a higher price than a polycarbonate helmet.
For carbon fiber, the main pros are its high rigidity, which is why you mainly see it in sports applications, its very lightweight, and its performance in high-speed impacts. However, its cons are that it is less durable in an impact since it has higher rigidity.
So, you’ll definitely see the signs of an impact on the helmet. Carbon fiber helmets also generally come at a much higher price and, since the carbon fiber skin is generally so sought after, you also usually get fewer graphics.
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In the end, we more or less see how the conventional wisdom has remained just that. The weight results for these helmets were to be unexpected. And once you get to the more premium fiberglass and carbon fiber helmets, companies will put in the extra effort to compensate for additional noise. For safety, it really depends on a case-by-case basis since some polycarbonate helmets can have just as many SHARP stars as a full carbon fiber one, even though these helmets tend to be safer.