How Trek developed Ballista and Velocis, its two best racing helmets ever

It’s easy to think of a bicycle helmet as a simple thing. There’s not much to it, really. There’s a hard dome — that part goes on top of your head — and a strap to keep it in place — maybe with a gizmo to tighten in. There you go: A helmet engineered.

Trek’s all new Velocis and Ballista helmets show just how far human ingenuity and advanced technology can push even the simple helmet, however. They were designed with different goals in mind. The Velocis is Trek’s lightest and coolest (temperature-wise; vibe-wise is up to you) helmet ever. Ballista is, quite simply, the fastest. The story of how they came to market shows just how limitless good science can be.

“After we develop a helmet or a bike, I’m like, ‘Oh man, it’s gonna be hard to get the next one to be faster because I feel like we did everything we could on this one,'” says John Davis, Trek’s aerodynamics lead. “But technology helps us expand. And what we did with Ballista and Velocis was look at multiple positions and multiple speeds. And as we can simulate more things and simulate them better, we’re going to continue to have a better understanding.”

Looking at where Trek’s engineers ended up, it’s hard to fathom how much more they can improve. The new Velocis — the official race helmet of both Trek-Segafredo and Trek Factory Racing — is empirically lighter (at 265 grams), faster and keeps your head 38 percent cooler than the previous generation when compared to the original Ballista. The new Ballista is the fastest helmet Trek has ever produced by a full order of magnitude, with savings of 10.1 watts (approximately one bike length difference over the course of an 8-second sprint) compared to the new Velocis.

In addition, Trek’s helmets are very good at … well, being helmets. Both utilize Mips Air safety systems and carry five-star safety ratings from Virginia Tech’s third-party testing facility. And both Velocis and Ballista share a host of improved quality of life features, including secure sunglasses storage, a flexible BOA 360-degree fit system with two lace height positions and a beveled front lip for improved visibility. 

That’s a lot of features adding up to make a simple “helmet” something so much more. How the new Velocis and Ballista came to be so robust is a long story. It began four years ago when Trek engineers sat down with one of the most valuable resources for product feedback at the company: Trek-Segafredo riders.

Michael Cech, the lead engineer on the Ballista, recalls meeting with the team at training camp in Mallorca and talking to them about what they liked and disliked about the Bontrager XXX road helmet. 

“They wanted it lighter, they wanted it better ventilated, they wanted it, of course, more aerodynamic. And then there were a lot of little details like sunglasses storage,” Cech says. “We almost had a year or two of XXX information that really went into the Ballista.”

From there, Trek engineers hit the lab.

Davis ran thousands of computer models — what the engineers call “CFD,” which stands for “computational fluid dynamics” — to help come up with the absolute best viable designs to accomplish the aerodynamic and air flow goals for both helmets. From there, they built physical prototypes and began the next phase of testing and polish. Enter: The wind tunnel.

For very good reasons, real life riders aren’t brought in right away to test the prototypes. Helmets need to pass stringent standards before they can be used during an actual bike ride. Instead, the engineers brought in their good friend “Manny,” who is incredibly good at sitting still for long stretches so that engineers can test how wind interacts with helmets at various speeds, angles and body positions.

You see, “Manny” is actually a specially designed mannequin (haha) for the express purpose of strapping a helmet on it and putting it through a battery of tests.

Manny was crucial to the development of both helmets. Because for as far along as the technology behind CFD have come, Trek’s engineers couldn’t extract all the data they needed from computers alone. They needed to run real-life tests to make their final adjustments. And it’s through wind tunnel testing that the Ballista’s engineers made their biggest breakthrough with a thin trough just behind the crown of the helmet called the “air trip.”

The air trip is what gives the Ballista the biggest aero benefit over any helmet previously developed by Trek. In layman’s terms, it works like the dimples on a golf ball. On a perfectly smooth helmet, air would stick to the surface until a point towards the back, at which moment the air detaches from the helmet and becomes a swirly mess of turbulence that creates drag and slows down riders. The air trip, according to Davis, “will kind of trick the air,” causing it to artificially “trip” into turbulence before it would naturally, and then suck back down to the surface of the helmet before eventually detaching with less drag.

Even once the Ballista engineering team decided they wanted to use the air trip, however, it still took a lot of trial and error to perfect. The team made multiple prototypes, hoping to find the perfect width, depth and location of the air trip to make the helmet soar. Finally, on their last trip to the wind tunnel, on one of the last prototypes that they made, the engineers had their eureka moment.

“It was almost the last helmet design that we kind of just threw in there,” Cech says. “We tried to make it as good as possible. And that last helmet design just blew everything away. It made this huge improvement of 50 counts of drag. And we were like, ‘Finally.'”

The engineers tested the air trip on Manny both in the drops and on the hoods, and found that the air trip made riding faster in both positions. No matter how someone rides — even at sub-pro peloton speeds — Ballista can give them a boost.

“The whole design brief for the helmet was we wanted to make sure that it was robust,” Davis says. “You can really optimize a helmet to be good in one little position, but as you’re moving your head around, the air won’t be able to hang on and stick to the back of the helmet. It’ll separate, and it’ll create a big wake of drag behind your head.”

For Velocis, becoming more aerodynamic was a tertiary goal behind becoming lighter and cooler, but in accomplishing those goals it achieved aero savings, too. After all, “cooler” is largely a way of saying “better air flow,” and with less material used in its design, it also carries a smaller, more aerodynamically friendly profile.

Still, testing for the Velocis was a more delicate balance than for the Ballista. The latter had one goal: “Go fast.” The Velocis needed to strike a balance of temperature, weight and speed, ideally without sacrificing one trait for another.

“The main thing with Velocis is keeping riders’ core temperature down during the hours and hours that they’re riding,” Davis says. “And so we’ve looked more at that relaxed position, where they’re going to be riding in the peloton for a long period of time, and optimized the drag so they use less energy for that position. And then we also optimize the cooling. But then we also study the more aggressive position there, too.”

The Velocis had one other hurdle: The fact that the old Velocis is still a really good helmet.

“We were looking at the smallest changes,” says Jesse Garrison, the lead engineer on Velocis. “The team hadn’t specifically asked for a new helmet outside of the fact that they were always looking for improvements. They said, ‘Can we make it lighter? Can we make it more aerodynamic? Can we make it better ventilating?’ That’s what we heard in our ongoing conversations. And once we decided what we thought we could improve, then we set up our R&D, and that’s when we really started interacting with the team.”

Somehow, the latest generation of Velocis improved in all aspects. Once again, the wind tunnel was the engineers’ litmus test. Garrison designed a special head form for Manny that allowed the mannequin to receive temperature readings across nine different zones on its noggin.

Velocis’ big breakthrough came in its construction. The helmet integrates carbon fiber thanks to production advances since the last helmet came out, which allowed the engineering team to eliminate components and create a sleeker helmet. 

“We leaned pretty heavily on our carbon experts in Waterloo,” Garrison says. “Brands have used carbon before, but we aimed to do it in a very different way. We incorporated more carbon than is typically found on other road helmets and we’re really happy with both the look and performance.“

Garrison is particularly proud of the Velocis’ fit pads. Riders had complained in the past that the pads that help keep the helmet comfortable on their heads also create a sort of greenhouse effect inside the helmet when combined with the plastic layer above it. The new Velocis incorporates that plastic layer into the fit pads, eliminating the mini oven atop riders’ heads while also shedding a few more grams of material.

Garrison also worked with Mips to add perforations to the back of the fit pad, allowing sweat to evaporate more easily, creating even better cooling and a better overall experience for all riders. The results from on-road testing were definitive: Riders reported a vast improvement.

“When you put it on a rider to ride for testing, which we did, whether it be pro riders or people inside the building, it made a very noticeable difference empirically of old versus new,” Garrison says. “The fit pad reduces sweating on your face, which is just more comfortable, but also actually cools you better, and it also weighs less. So all of those things are working in tandem, which is awesome.”

The fit pad system worked so well that it was also adopted by the Ballista engineers. The two teams worked closely together to optimize each other’s work. As a result, both helmets accomplish much more than their primary goals. The Velocis is still a very good aero helmet, and the Ballista is still light and cool enough for everyday use.

“It was a really good collaboration between the two projects, of taking research from one, utilizing that to springboard the research for the next, and then sharing some of the knowledge and the parts,” Garrison says. “And we worked with Trek-Segafredo more extensively on this and the Ballista than I think we ever have in the past, and I think it shows in both those products.”

Throughout the engineering process for both helmets, athletes were kept abreast of progress. They got to see every step of development so that engineers would always know they were on the right track, even if that meant revealing a few early warts.

“Early on, we had a really rough model to show to Mads [Pedersen], and Mads’ reaction was like, ‘That thing looks ugly,'” Cech laughs. “At that point, we had industrial design jump in. They really give the helmets the nice appearance we think of — the graphics and the styling — and then the next time we were able to show Mads the full renderings from ID, he loved it. He was like, ‘Wow, I like that thing.'”

Pedersen was one of the Trek-Segafredo riders that engineers most wanted to impress. Not only is the former World Champion talented, but he’s versatile as a classics specialist who also tackles the varied terrain of marquee events like the Tour de France. The perfect helmet for Mads would have to suit him for daunting mountain climbs as well as full-gas sprints.

“Mads has been really great to work with. He’s definitely into aerodynamics and getting as much speed as he can,” Cech says. “It was kind of nice seeing that progression as we were making little improvements, showing him renderings, getting him to really like how it looked. And then when he was finally test riding early versions, he was continuing to like it more and more.” 

Both helmets were given to riders during the offseason after passing strenuous internal and external certification standards. At that point, the engineers held their breath as they waited for the final feedback on the few elements they could still change before launch, and hoping — maybe praying, more likely — that the riders had no unsolvable gripes after a year and a half of research and development and four years of brainstorming.

Instead of critiques, however, the engineers heard the best sound of all: Nothing. 

“When we actually gave them real helmets and they were test riding, it was almost like no news is good news,” Cech says. “We didn’t hear complaints. Usually, if you hear feedback, it’s about things that are wrong with it. In this case, we didn’t hear much. It was just, ‘Everything’s good.'”

And that was that. Trek athletes have been enjoying the fruits of Trek engineering’s labor for several months, and now, starting today, you too can see what all the fuss is about. And though volumes can be written about the development of the new Velocis and Ballista, there’s no need to think about it too hard. Just strap in and feel confident that a lot of sweat, passion and good old-fashioned science went into making sure you have the absolute best and safest ride possible.