The new Klim F5 Koroyd helmet and the technology that sets it apart

In short, it's because of the technology.

The technology

Two main features set the new F5 apart from other helmets: The Koroyd liner and Fidlock chin strap closure.

The new F5 Koroyd is the first motorcycle helmet that replaces entire sections of its internal impact absorption liner with Koroyd welded tubes. According to the Koroyd website, the tubes compress under pressure, dissipating the energy from an impact and reducing final trauma levels. At this point you should be saying to yourself, “Well, OK, but that works like the EPS liners in other helmets on the market. How is this different from my current helmet technology?”

Koroyd is claiming advantages in ventilation and weight, as well as being a leader in reducing the amount of force transmitted to one’s head in the event of a crash.

Because the tubelike structure is completely hollow, it allows air to flow freely in the helmet with minimal obstruction. While the design helps increase airflow to the head while riding, the real benefit is the amount of hot air it allows to radiate away from the head while sitting still.

Because the final structure of Koroyd is 95 percent hollow, it is extremely lightweight. As you can see in the graphic above, Koroyd is used in the center portion of the helmet. Traditional EPS is used on the sides and it's all encased in a carbon fiber shell. With this combination, Klim set out to keep the weight down while maintaining enough rigidity to pass DOT regulations, thus making this dual-sport helmet street-legal.

Koroyd claims a reduction in Head Injury Criterion or HIC. HIC is a measure of the likelihood of head injury arising from an impact. In addition to reducing the g-force transmmitted to the head in a direct impact, Klim also utilizes a Multi-directional Impact Protection System (MIPS) liner to aid in the reduction of rotational force transmitted to the head. MIPS, however, is nothing new. Rather it has been implemented by multiple big name helmet manufacturers at this point to aid in the reduction of rotational impact injuries.

The Fidlock chinstrap closure also makes its debut with this helmet. (While I've seen this before on a snowmobile lid, this is the first time I've seen it on a motorcycle helmet.) Think of Fidlock as two magnets that easily lock together but can only be separated if pulled apart in one specific direction. The result is a helmet strap that is extremely easy to lock into place or remove in a hurry.

Testing the F5 Koroyd

Over the past two months I have logged roughly 1,000 miles with this helmet in a combination of on- and off-road situations.

I first used it at the KTM Rally East in Snowshoe, West Virginia for a combination of dirt and paved roads. I was pleased to find that there was minimal peak lift when riding at street speeds. Even though it has a shorter peak than found on other dirt lids I own, it was rare that I found myself wishing it was longer.

At AltRider’s Conserve the Ride, Jeremy LeBreton, AltRider’s charismatic leader, was rocking the F5 Carbon without Koroyd. He raved about the Fidlock system, which is found on the base F5, as well. I can’t imagine it’ll be long before you see this technology work its way into other helmets in Klim’s lineup.

All of CTR was spent riding in extremely high temperatures and I welcomed the additional venting. Two weeks after that, I headed up to Canada to participate in the Dacre Challenge, a long-distance, off-road ride in the wilds of Ontario that pushes riders to the limits. Temps ranged from the mid-50s to the mid-80s. While I was happy to have this lid in the slow-moving, swampy single-track, it flowed almost too much air during the long, cold stretches on the main roads. (There is a windstopper liner but I did not have one with me to try out.)

Lastly, I participated in the NE 24-Hour Endurance race. It was my first official race and my first time riding a two-stroke dirt bike. I had one good crash, luckily landing on my head, not my bad knee. I was able to continue, unfazed. So, from what I can tell, it did its job from a impact perspective.

Ups

• The F5 Koroyd is easily the best venting helmet I’ve ever used. If you are like me and tend to overheat easily, this is definitely technology to consider. I am interested to see how this can be incorporated into a street helmet.
• The Fidlock system is a game changer, plain and simple. I have talked to a few riders who have used it and they all love it. I can’t imagine we’re not going to see other manufacturers adapting this technology to their helmets sooner than later.

• It utilizes MIPS technology for rotational impact protection. I’ve hit my head pretty bad in two separate off-road crashes and both times I was in a helmet with MIPS. While I can’t say for certain that’s what saved my noggin, I can say I wasn’t mad I had it. MIPS is not available on the base F5.

• It is street-legal. Which is perfect for all of you adventure and dual-sport riders who prefer riding in a full dirt bike helmet as opposed to a street-oriented adventure lid.
• I love how easy it is to get the cheek pads in and out. I am constantly installing different cameras and com systems in my helmets and these pads have a rigid backing that helps them hold their shape and snap into place easier than most.
• Fit and finish are on par with what you’d expect from a $650 helmet.

Downs

• At three pounds in a Large, the F5 Koroyd weighs six ounces more than the regular F5 Carbon, which tips the scales at two pounds, 10 ounces. The additional weight is attributed to the extra material used in the MIPS system as well as changes made to get the Koroyd to pass DOT regulations. The base F5 is not a street-legal helmet, which is only a concern if you are using your bike on the street, as well as the dirt.

• It takes a few rides to get used to the Fidlock system. There were a couple of frustrating moments in the beginning when I was stuck in my helmet, cursing as I was trying to get it off my noodle.
• Sizing is off. I am typically a XL in brands like Shoei and Arai. I had to size up to a 2XL to get this to fit correctly. Because there are only two shell sizes, folks in those middle sizes are going to end up with a physically bigger helmet than they would in other brands with more specific shell options.
• It’s not designed to easily accept a traditional com system mount. In order to use my Sena 20S clamp mount, I essentially had to pull the helmet liner apart from its carbon fiber shell. I would imagine this is not something that a lot of folks are going to want to do on their brand-new helmet.

Conclusion

Like I mentioned at the beginning, we tend to shy away from product reviews on Common Tread. We have plenty of product information elsewhere on the site, so we highlight products in Common Tread only when we think they represent a significant variation from the norm that's newsworthy.

Regardless of whether you ride in the dirt, the technology introduced in this helmet is sure to have a lasting impact on the helmet industry as a whole. I am interested to see where it goes from here. I would readily buy a street helmet for summer use that utilizes these same features.

As for my personal Klim F5 Koroyd helmet? It has taken the place of my old Shoei VFX-W as my go-to dirt lid in my arsenal of noodle protectors.