Limited appeal for riders with average-shaped heads, but a potential revelation for outliers.

Helmets might seem like an odd place to use additive manufacturing until you consider all the people who can’t find the right fit from an off-the-shelf model, and how comparatively simple it is to make one-offs using a 3D printer (theoretically speaking, of course). KAV Sports’ new 3D-printed Portola helmet isn’t the best helmet on the market in terms of traditional metrics like safety, weight, or ventilation, so it’s a tough sell if a standard model fits you well. But if nothing has ever felt right to you in the past (and you’re willing to stomach the cost), it might also be exactly what you’ve been hoping for.

Conventional helmets are made using expanded polystyrene foam liners with co-molded polycarbonate shells. In contrast, KAV prints each Portola at its California headquarters using only a nylon-based and carbon fiber-reinforced “tri-blend thermoplastic”. Those strands are arranged in a honeycomb-like cellular structure that absorbs impact energy via wall deformation (similar to Koroyd or Bontrager’s WaveCel design) — sort of like stomping on an empty beer can. According to KAV Sports, there’s no need for a separate component to handle rotational forces; that sort of shear deformation is supposedly built into the cellular structure (just like WaveCel).

Instead of a separate shell, the fibers in the Portola are the shell. The surface isn’t glossy-smooth like what you might see on a traditional helmet, but it’s not far off from some matte finishes. KAV Sports has done an impressive job of refining the surface roughness, especially considering the helmet is printed in sections that are joined together later. There’s one consequence of the integrated “shell”, though: the Portola is only offered in black.

KAV Sports prints the strap sliders from the same material, and the pads are rather unique, to say the least. Instead of the usual chunks of fabric and foam, each is made of a swatch of skin-friendly foam rubber applied to a printed nylon base that floats on a pair of plastic coil springs. According to KAV, this boosts comfort by minimizing contact area and essentially suspending the helmet off of your head. There’s also enough pad travel to accommodate things like winter or summer caps, or even seasonal changes in hairstyle. 

Interestingly, the Portola does without a supplemental rear retention system of any kind, instead relying more on the exactness of the fit to provide a stable hold, together with a traditional four-point nylon webbing harness and a fancy Fidlock magnetic buckle.

“The retention system in a few-sizes-fits-all helmet is required to eliminate slack between the inside of the helmet and your head,” explained KAV co-founder Whitman Kwok. “Without it, the helmet would wobble on your head during casual riding and would likely roll off your head during an accident. The Portola benefits from removing this extraneous hardware. The combination of a made-to-measure helmet and automatically adjusting fit pads obviates the need for a ratcheting system so you have one less thing to fiddle with, less weight, nothing to interfere with or catch your hair, and one less thing to break.”

Each Portola helmet is fully custom-built. Once someone places an order, KAV Sports sends out a measurement kit, which is then used to build out the custom headform after an online follow-up consultation. For special cases (or if there are any questions), a custom printed “fit cap” is also sent to the buyer to first verify the fit before production begins. Claimed target turnaround time from when a fit is finalized to when a complete helmet heads out the door is just a couple of weeks.

Although each helmet takes a long time to print, there’s supposedly almost no waste produced, and since each helmet is custom-made, it’s not like the company has a bunch of finished product sitting on warehouse shelves eating up raw materials, either. 

Currently, the Portola has received CPSC certification so that it can be legally sold in the United States, but approval for other regions is still pending and independent test results from Virginia Tech aren’t expected until the end of the year. That said, the company claims the Portola is “at a minimum 25% more impact resistant than what is required by industry standards.” Take that as you will. 

Either way, KAV backs the Portola with a 30-day money-back guarantee, along with a five-year warranty that includes a one-time, no-cost crash replacement. That sort of coverage is better than average, but then again, the Portola is anything but inexpensive. Current retail price is a whopping US$390. 

If you feel like you’ve seen something like the Portola before, you’re right. British brand Hexr got into the 3D-printed bike helmet game back in late 2018, using a similar hexagonal honeycomb structure. Hexr uses a separate snap-on shell, though, as well as a different printing process that uses laser sintering to produce the entire liner in a single part instead of the Portola’s multi-piece design.

Hexr also uses a plant-based renewable material for its printing powder (it’s made from castor beans, like some sunglass frames), there’s an option for a Boa-based retention system at the back, and while the Portola only comes in black, Hexr’s use of a separate snap-on shell allows for a white option, too (and, at least the possibility of additional colors later).

Pricing is similar with the Hexr pegged at £300, not that anyone will be comparison shopping, though. Hexr’s helmet is certified for European markets, but not US or Australian ones.

So yes, the two helmets are similar, but still different.

“Other than being 3D-printed, we’re completely different,” insisted Kwok. “Hexr outsources manufacturing using existing printers, off-the-shelf nylon, and comes in a handful of shell sizes that they then fill in for a custom fit. KAV utilizes a fully integrated customization platform which gives us more control and increased performance. We developed our own carbon fiber composite polymer, wrote all our own software, and redesigned existing 3D printers to make a fully custom helmet. So rather than taking one of a few fixed shell sizes and filling the space, we take your head dimensions and build out. The difference is like picking between a few different frame sizes and adjusting your seatpost, stem, and handlebars to fit your bike, versus having a custom frame builder build your bike frame from scratch. The latter allows us to tune every aspect of the helmet, removes excess material, and keeps the offsets consistent across all our helmets for the slimmest and most aero profile possible.”

To say the Portola isn’t like most other helmets on the market would be quite the understatement. It’s made differently, it fits differently, it looks different, it feels different. In fact, there are almost more differences than there are similarities.

Nevertheless, the Portola acts like a good conventional helmet in many ways when you’re using it.

For one, it’s quite comfortable to wear — as it darn well should be considering it’s custom-fit to your own noggin — although that’s not just because of the uncannily perfect shape. Those goofy spring-loaded pads feel weird when you first put the helmet on, but as promised, they evenly suspend the Portola a few millimeters off of the surface of your scalp, leaving just a handful of points of gentle contact behind. Perhaps it’s due to this minimal contact that the Portola feels sometimes barely-there, but whatever the reason, the end result is the same.

Appearance-wise, the Portola is pleasantly trim and low-profile, hugging the contours of your head just as it should. Ever feel like off-the-shelf helmets turn your head into a mushroom because they stick out so much? That shouldn’t be an issue here.

By conventional measures, the Portola should be a bit of a sweatbox. There aren’t a ton of vents, there’s virtually zero internal channeling, and previous experience with other cellular-type helmets such as from Smith Optics and Bontrager have repeatedly demonstrated less-than-optimal airflow. But surprisingly, the Portola is pretty good in this respect.

You can feel a lot of air whooshing across the top of your head even at moderate speeds, and I expected the Portola to be much more stifling on slower climbs than it actually is. I’ve certainly worn helmets that felt much, much warmer than this one.

The Portola’s curiously good ventilation performance is likely related to how the helmet is semi-suspended off the top of your head. This seems to make up for the lack of dedicated internal channeling by creating airspace between your entire scalp and the helmet liner for air to pass through from front to back. In some ways, the Portola reminds me of Giro’s Vanquish aero helmet, which has minimal exterior venting, but such efficient internal channeling that it’s far cooler than it looks. 

Riders who don’t shave their heads like I do might not experience the same thing as I did, however, since that cooling mechanism won’t be nearly as efficient once the space is filled with hair. And either way, sweat management is entirely non-existent. Those springy pads may do wonders for how the helmet fits, but they’re entirely non-absorbent so perspiration has nowhere to go but drip down. Some sort of cap or sweatband (or a dedicated widget like a Sweat Gutr, Halo headband, or Veo strip) is an absolute must, even in cool conditions. And thankfully, those springy pads accommodate a typical cycling cap with no issues at all.

I obviously didn’t personally test the impact-absorbing capabilities of the Portola, but one element of its design still gives me pause. Although coverage is pretty good around the rear of the helmet, the front and sides are cut quite high. Even the models on KAV Sports’ own web site have an awful lot of forehead showing. The Portola may proudly wear a CPSC certification decal, but when the primary purpose of a helmet is to protect the wearer’s head and brain, coverage isn’t an area I like to see corners being cut.

“We made the Portola for modern road and gravel riding and so we wanted to provide additional coverage to the backside for all the reasons MTB helmets do,” Kwok explained. “We didn’t find in impact testing that the front or side height had any adverse issues (and exceeded any certification requirements for coverage) and had a few benefits. On the front, ventilation improves with a slightly higher drip line. On the side, we found increased compatibility with all the sunglasses cyclists wear.”

Regarding of what KAV’s testing shows, my particular test helmet may very well highlight one of the pitfalls of a custom-made helmet. Although CPSC guidelines expressly prohibit this, I’m able to torque the Portola completely off of my head if I push hard enough from the front. Basically, once the rear of the helmet is past the occipital bone, the fit security goes seriously downhill — and that’s with the harness adjusted so that I can barely fit a finger between the strap and my chin. 

From what I can tell, this issue is primarily related to that high cut up front, and perhaps also how the forward straps are anchored in the helmet body slightly further back than average.

Either way, this isn’t something I can do with any other helmet I’ve ever tested (and I’ve tested a lot of helmets in my day).

“There are six retention tests for CPSC and we exceeded all of them coming in below half the threshold of allowed movement,” Kwok said. “As far as I know from doing comparable tests with existing helmets, we compare favorably to your standard foam helmets.”

The Portola is also noticeably heavy with an actual weight of 354 g, which is even more of a bummer given my smaller-sized head and the lack of a traditional retention system. Riders with larger heads who may have historically struggled to find high-performance helmets that fit well will be most likely to be drawn to the Portola’s custom-printed concept, and those helmets will obviously be substantially heavier. 

Other complaints are more trivial.

The Portola’s shape looks nice enough, but it’s somewhat ironic that a helmet touted as being entirely customizable for fit isn’t at all customizable for something as basic as color. Lots of riders prefer black helmets, anyway — but lots of riders don’t.

The lack of sweat management obviously makes it challenging to wear sunglasses if stuff is dripping down into your lenses. The outer forward vents on the Portola are well positioned for stashing your eyewear, but their small size makes for a tricky target while riding, and without any gripper material on the helmet surface, glasses don’t always want to stay put. 

Finally, there’s the sky-high cost. That’s not to say the price isn’t justified all things considered, but the Portola is almost 60% more expensive than a new Giro Eclipse Spherical, which — potential fit issues notwithstanding — also happens to be a better helmet in every regard. Granted, KAV Sports backs that price up with a five-year warranty as well as a one-time, no-cost crash replacement within that period, but it’s still a big chunk of change.

One thing that shouldn’t go unmentioned is KAV’s rate of product development. According to KAV, my test helmet (which was just made less than two months ago) is internally classified as v68; the company is already on v75. KAV can’t make massive changes without having to have the helmet re-certified, of course, but since the company does everything in-house, smaller changes are quicker and easier to do — so hopefully some of my complaints can be addressed sooner than later.

The Portola is a good helmet in many respects: it’s decently ventilated, the fit is perfect by definition, it’s comfortable, I think it looks good, and it’s made with cutting-edge production methods. But if you ignore the custom fit aspect, just being good isn’t nearly enough to justify the price of entry in this incredibly competitive market. It’s heavy, the ventilation is good but not great, the sweat management is non-existent, the coverage isn’t as comprehensive as I’d like, and it only comes in black. 

That’s assuming an off-the-shelf model fits you, though.

If you’ve struggled in the past to find a helmet that fits the way it should, the Portola may just be a godsend. After all, even the best helmet on paper isn’t worth much if it doesn’t fit you. And for riders who’ve never been happy with anything else, just being “good” may as well be flat-out amazing if there aren’t any other options. 

But aside from outlier buyers, the Portola carries too big a price premium and too many compromises for it to be a sensible pick over other options that just perform better. 

More information can be found at www.KAVsports.com.