MO Tested: KLIM F5 Koroyd Helmet Review

Ryan Adams
by Ryan Adams

Lightweight, more breathable, and safer

Since receiving the KLIM F5 Koroyd, I’ve put a lot of miles into this lid. Long freeway miles and multiple days back-to-back in the dirt, in both hot and cold climates. The F5 Koroyd has performed very well, thanks in part to the technology and development that has gone into this helmet. As KLIM has done with many other products throughout its lineup, the F5 Koroyd is a collaboration between KLIM and other leading companies in an attempt to truly make the best helmet possible.

The DOT/ECE rated F5 Koroyd’s standout features can be broken down into three parts: light weight, ventilation, and safety. The first of which has been achieved with the use of premium construction materials and class-leading technology.

The F5 Koroyd’s outer shell is made up of KLIM’s Karbon Fiber. In an effort to keep weight down with the lightest material currently being used across the market, this helmet is also available in three shell sizes to keep the helmet as physically small as possible coordinating with the user’s helmet size.

Those sections of welded green tubes are Koroyd panels integrated into the EPS.

The use of Koroyd technology in this new F5 actually adds to all three of the features mentioned above. Constructed from sections of welded tubes, Koroyd claims its material provides 48% more energy absorption than other standard EPS style foam liners on the market. First developed for the commercial airline industry, Koroyd is now being used in many different helmet applications across industries such as cycling and construction and also in items such as elbow and knee pads, back protectors, and even skis.

The Koroyd tubes work extremely well for ventilation. A key element of the F5 in its original iteration was to provide ample venting to allow heat to escape while working in more technical terrain at lower speed. Koroyd takes this to a new level. While moving, the helmet expels heat with the best of them, but its while working hard in tight terrain and while stopped that the F5 shines. It instantly flows heat from the back and top of your head through the vents and welded tubes to provide excellent heat dissipation in hot climates. I have used this helmet on plenty of long trail rides in the desert and in tight conditions where I’m working up a sweat. I’ve never kept a cooler head, literally.

The ventilation is fantastic and the Fidlock HOOK 25 fastener makes pulling the helmet on and off a breeze.

Of course, if you’re stopped to chat for a minute between trails, it’s also incredibly easy to throw this helmet on and off. My second favorite feature of this helmet aside from the ventilation is the use of the magnetic Fidlock helmet strap fastener. Fidlock’s website offers a nice demonstration of how the system works which can be seen here. The Fidlock HOOK 25 aluminum fastener lets users pull the helmet on and off quickly with the magnetic closure easily giving a positive lock and releasing effortlessly when pulled the correct way. I wish I had more helmets with this fastener.

Koroyd, MIPS, and KLIM have come together to bring a safe, lightweight lid that can be used on-road or off.

Koroyd isn’t the only safety enhancement for the F5, this version also comes with MIPS multi-directional impact protection system. MIPS was developed by the Swedish brain surgeon Hans von Holst and is designed to add protection against rotational motion transmitted to the brain from angled impacts to the head. MIPS is now being used by many bicycle and motorcycle helmet manufacturers, with applications in the snow and equestrian industries also. Between the Koroyd layer and MIPS technology, the KLIM F5 Koroyd is one of the most technologically advanced helmets on the market in terms of safety. We applaud KLIM for bringing together Koroyd and MIPS within this new helmet in an effort to really make a safer product for us riders.

But wait, there’s more! Though the KLIM F5 Koroyd works well in hot climates, KLIM hasn’t forgotten where they come from. Cruising fast through the mountains on a sled, you may not want all of that ventilation open all the time. Along with a nice helmet bag, the F5 Koroyd comes with a Gore Windstopper skull cap that can be fitted between the removable Drylex liner and the Koroyd layers above it, blocking ventilation for chilly days. Also included is a cloth plastic-reinforced breath deflector for keeping your face warmer in cold weather, and an extra peak with hardware should you need it.

The F5 Koroyd isn’t bad on-road either. That being said, if I know I will have a long haul on the pavement before I get to the dirt, I would remove the peak for longer highway blasts and put it back once I’ve reached my dirtstenation.

My only complaints are that the helmet feels somewhat larger physically and that there is no additional protection, removable or not, for the nose. The fact the helmet looks and feels somewhat large doesn’t bother me though since it’s lightweight. My helmet tips the scales at 3-pounds 3.5-ounces, but I would still like a little more nose protection. If you’ve ever been hit in the tip of the nose with roost or the odd rock, you know what I’m talking about.

Overall, I am very happy with the KLIM F5 Koroyd. I look forward to using it as temperatures rise out here in the California desert. At $649.99, it’s not cheap, but with the collaboration of companies that have come together to make a great product, we think it’s more than worth it.

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Ryan Adams
Ryan Adams

Ryan’s time in the motorcycle industry has revolved around sales and marketing prior to landing a gig at An avid motorcyclist, interested in all shapes, sizes, and colors of motorized two-wheeled vehicles, Ryan brings a young, passionate enthusiasm to the digital pages of MO.

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Join the conversation
  • Spiff Spiff on Jan 26, 2019

    Kind of seems like the next gen of helmets. I will consider this if I end up with a dirt bike.

  • Old MOron Old MOron on Aug 26, 2020

    Good review, Ryan. We've been using styrofoam to protect our noggins for so long. This new technology is very interesting. Any idea why they use koroyd only on the center line of the helmet, and not on the sides?

    • Ryan Ryan on Aug 28, 2020

      According to KLIM, the main reasons that Koroyd isn't used entirely at this point in time is shape, comfort, and cost. The shape of the Koroyd isn't tapered at all so it can only handle a certain amount of curvature. Comfort-wise, EPS still provides a softer "feel" where the head may more consistently come in contact with the material. The Krios Pro ADV helmet does actually use more Koroyd though than the F5 so who knows what we may see in the future.