Helmets: Where to spend your money

What you should — and shouldn't — pay for when buying a brain protector

Helmets Tech
The first thing to focus on when selecting a helmet is its shape, and how it fits your head, which varies depending on the manufacturer. Photo courtesy of Art's Cyclery

The first thing to focus on when selecting a helmet is its shape, and how it fits your head, which varies depending on the manufacturer (click to enlarge). Photo courtesy of Art’s Cyclery

Editors Note: This article was written by Art’s Cyclery web content editor Brett Murphy, who uses his mechanical engineering background to explain the latest industry advances and breakdown component design. The original post can be found here.

With cycling helmets ranging wildly in price, you might be wondering what the heck’s the difference between the Giro Saga ($65) and the Giro Synthe ($270). Both helmets have to pass the same impact testing standards, and are even constructed from similar materials. So how do you decide which is best for you?

The first thing to focus on is shape, and how the helmet fits your head, which varies depending on the manufacturer. Art’s Cyclery uses a comparison system for classifying helmet shape, or ovality, across brands. Each helmet is categorized as having an oval, intermediate or round fit, expressing the ratio of the width of the helmet to the length. While two helmets can both be sized for the same head circumference, one could be much wider and shorter than another.

Road cyclists will be far more concerned with the aerodynamics of a helmet than mountain riders. More expensive road helmets (such as the Giro Synthe) often have extensive design, engineering, and testing involved to reduce aerodynamic drag. The video below gives you an inside look at design process of that wind cheating brain protector.

Next, consider the helmet retention system, which includes straps that run in front and behind your ears and clasp together under your neck. The helmet will also have some sort of a ratcheting mechanism that adjusts to the circumference of your head. Each type of ratchet offers different advantages. If you like to make adjustments on the fly for instance, Lazer offers helmets with a small dial on top of the helmet for easy and quick access.

While helmet features like these are important to consider, the real reason to wear a helmet is to protect your brain. Magnetic snap-on eye shields are awesome, but useless if the helmet doesn’t provide adequate protection in a crash. That leads up to the main structural technologies that protect your noggin in a worst-case scenario.

Most helmets are made of EPS (expanded polystyrene) foam liner bonded to a harder shell. Helmets have not strayed far from the proven foam liner/hard shell design since EPS foam was first used in the mid-1970s.

EPS foam helmet liners begin life in the form of small beads of styrene that are later paired with an expanding agent. As the beads are heated, they expand, and are then packed into a mold of the helmet shape. Less expensive helmet models will feature a shell that’s taped or glued to the outside of the EPS. In-mold technology, seen on higher-end models, allows the foam and shell to be molded together.

This process allows for more aggressive and aerodynamic features to be incorporated, along with increasing the helmet’s impact absorption capabilities. In-mold also allows for more ventilation while maintaining structural rigidity. Helmet shells protect the foam from abrasion due to regular wear and tear, and vary from polycarbonate to carbon fiber. Shell material, ventilation, and engineering costs will also play a role in determining price.

Composite Fusion Plus Cutaway
 
Kali cone-head construction (click to enlarge). Photo courtesy of Art’s Cyclery

When your helmeted head hits the ground, the helmet you are hopefully wearing will absorb most of the impact force. This happens through a combination of the shell and EPS foam deforming, engineer talk for getting crushed, with the foam absorbing most of the force. Denser foams require more force to cause deformation, which some manufacturers interpret as a reason to make very dense, thin helmets, which still meet the safety testing requirements. Critics point out that dense foam creates more impact resistance in the helmet, but actually passes more impact force on to your head.

Some helmet companies, such as Kali Protectives, use multiple density EPS construction. This allows for much more control over how the forces are distributed through the helmet. Kali’s Cone-Head technology allows multiple-density designs with lower density foam closer to the head and higher-density foam closer to the shell. This creates crumple zones within the helmet for more effective dispersal of impact forces across more of the helmet, which does a better job of keeping the forces from being transferred to your head.

Continue to page 2 for more helmet buying advice and an explanantion of MIPs technology »
About the author: Arts Cyclery

This article was originally published on the Art's Cyclery Blog. Art's Cyclery is dedicated to offering free expert advice, how-to videos, and in-depth product reviews on ArtsCyclery.com to help riders make an educated decision when selecting cycling gear.


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  • Kevin says:

    I just picked up a Smith Overtake MIPS helmet. It is light and feels good on my head. Used it on a few rides in 80/90 degree weather and it kept my head cool without letting sun light hit my head and heat-up and burn my scalp.

  • Don Cafferty says:

    This article does not answer the question of where to spend your money.

  • froze says:

    I read this article with much interest, even clicked on the Kali Protectives site to read more, in the end of my reading I had a question that came to my pea brain. Crush zone sounds good, it works in cars really well, problem is with a helmet you only have 1 inch of crush area at the most vs at least 48 inches in a car. Knowing that there is only 1 inch of crushable area in a helmet how much is that area really going to effect slowing down the effects of an head impact at say 14 mph (average speed of the average rider) to zero in 1/4th of a second? I think it’s nil vs other types of helmet construction; a point could have been made if the crush zone was say 12 inches thick inside the helmet but that would make the helmet to bulky. Unless I can see independent crash results proving that the Kali Protectives crushable zones work better than a standard helmet I’ll have a difficult time believing it, in the meantime I’ll call it hype like a lot of stuff sold on the cycling market.

    So where to spend your money? I say the sweet spot in a helmet to get quality materials is $90 to $100, find it on sale for $45 to $55 and you got a great helmet as long as it passes the federal CPSC rules.

  • Marco Monteiro says:

    I felt from my bike at 63 Km/h and hit my head straight into the asphalt with my body weight on top of it. Everything was black for a moment and when I recovered I saw the damage on the helmet and couldn’t believe I was still alive. It was a 25 usd helmet from a ordinary approved company. I have a very hard time believing that a 300 usd helmet will do any better than that in similar situation. Definitely an overpriced piece of Styrofoam in most cases.

  • john riggs says:

    I can’t believe manufacturers are STILL only using EPS foam with all the material breakthroughs lately. This is OUR HEADS we’re talking about. It dosen’t take much to protect your cranium in a fall which is why I use a 20$ helmet from Wally World. They ALL have to meet the same ASTM ratings no matter the brand/size/price point. But I’m bewildered why more companies aren’t using a variation of densities that would decelerate better and dissipate energy better than the same stuff found in a cheap, disposable cooler.

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