The Kask Defender Offers Lightweight Full Face Head Protection [Review]

The Kask Defender full face mountain bike helmet is lightweight, well-vented, and pricey.

As a kid, I remember thinking that all helmets looked goofy — except those designed for motocross. The folks who rocketed through the forest trailed by a ribbon of blue smoke were the coolest, and their bright and shiny protective gear was the only kind I wanted to wear.

The Defender full face MTB helmet from Kask has a shape and aesthetic reminiscent of those head protectors, with a far lighter 916g total weight (sizes L-XL) and laughably more ventilation than any moto lid I have tried. The full carbon fiber shell is said to drop the weight of the size medium lids to 750g, but you’ll pay the price for that weight savings with a startling retail tag of €600 ($595 MSRP, available at JensonUSA for $500 currently).

The Defender meets both CE EN 1078 and ASTM F1952 safety standards, and the lid is held tight in place by a classic double-D-ring buckle. While this closure style is popular for downhill racing helmets that prize protection above all else, it’s definitely not my favorite. It’s frustrating to remove in a hurry, the gloves usually have to come off, and the strap has to be adjusted every time you pull the lid over your dome. A pre-adjusted Fidlock buckle is far more convenient, and none of the magnetic buckles I’ve tested have opened up on impact. I also haven’t heard of that happening to other folks. If you have a unique helmet strap preference or experience please share it in the comments below.

The cheek pads can easily be removed in case of emergency, and you can dislodge them for increased airflow while climbing in an enduro race. Some folks like to store the pads under one side of their goggle strap while climbing, with their gloves tucked in the opposite side for a solid Bullwinkle antler look. All of the other padding can be removed and cleaned or replaced, including the chin-guard air filter.

In addition to its carbon fiber featherweight, the Defender is notably breathable. There are 18 vents in total, but it’s the channels that connect them inside that make the difference. There is a full-on duct system inside this thing, moving air directly from the front vent holes to the rear like a roadie helmet. It seems the Kask product designers studied H-VAC before taking a job in the mountain bike industry. This is one of the most breathable full face buckets I have tested to date, rivaling some with far more open holes like the iXS Trigger FF.

Size large and XL helmets share the same shell with different size pads, and the XL is quite tight on my 61cm cranium. It offers a great fit for 5-15 minute spurts of safe gravity riding, with a secure grab on my head that definitely isn’t going anywhere. The lower portion of the internal foam layer is covered in a hard plastic that I find uncomfortable. It presses against the base of my skull enough that I’m happy to slide the helmet off at the bottom of each run and throw it on the handlebars. The defender wouldn’t be my go-to lid for enduro races where I would have to wear it all day, though for folks with smaller heads this may not be an issue.

Goggles get a nice little cubby under the visor, with several clicks of height adjustment to move it up and out of the way. The visor itself is rather flimsy, and I managed to break one without even crashing. The helmet fell a couple of feet from a shelf to my floor, snapping the little plastic arm that holds the bill in place. While it’s good to have these pieces break to keep the visor from rotating your neck in a crash, these seem overly fragile.

The field of vision is appropriately broad, with ample space for large goggle frames. When looking ahead and tracking your line the helmet frame disappears from view just as it should.

I have yet to crash wearing the Defender, but it seems like a solid safety unit. The hard carbon and inner foam liner take care of direct impacts, though there is no rotational impact system like MIPS to speak of. I bet the brand will have an update to this early 2020 release that covers those rotational impact forces.

Goggle-strap grippers on either side.

At €600 a pop I would have a hard time recommending this helmet to anyone, unless they make wheelbarrows of money and just really love the motocrossy looks. It is a good looking and well functioning lid with top-notch ventilation for anyone who doesn’t spit out their smoothie after seeing the price tag.

Check out our mountain bike helmet buyers guide and our picks for the best mountain bike helmets.

⭐️ Find the Kask Defender helmet at JensonUSA and Amazon.