I crashed at Leogang in 2019 and don’t remember the rock that split my helmet open. I remember the start loop, the compression before the rock garden, and then waking up in the medical tent with a headache that lasted three days. The helmet, a model I’d chosen mostly because it matched my kit, did its job. I’m still racing. But that moment changed how I think about the six inches of foam and plastic I strap on before every ride.
Most conversations about helmets focus on weight. I get it. When you’re racing ninety minutes at threshold, every gram matters or so we tell ourselves. But after that Leogang crash, I started asking different questions. Not “how light?” but “how does this thing actually protect me when I hit the ground at an angle I didn’t plan for?”
What I Thought I Knew, and What I’ve Learned
For my first few years at the elite level, I treated helmet selection like tire selection, something to optimize for conditions, weight, and sponsor obligations. I ran whatever was lightest within my sponsor’s lineup and called it good. The logic seemed sound: a lighter helmet means less fatigue on the neck over ninety minutes, which means fresher legs in the final lap.
That logic isn’t wrong, exactly. But it’s incomplete.
What I didn’t understand then and what took a concussion and a lot of reading to appreciate is that rotational forces during oblique impacts represent an entirely different threat than the linear impacts helmets were traditionally designed to handle. When you come off at speed and your helmet contacts a rock at an angle, your head wants to rotate inside the shell. That rotational acceleration is what causes many concussions, and traditional EPS foam does almost nothing to address it.
The introduction of MIPS changed this conversation. The low-friction liner inside a MIPS helmet allows your head to move slightly relative to the shell during impact, reducing the rotational energy transmitted to your brain. It’s not magic. It won’t make a catastrophic crash survivable. But for the more common scenario catching a root wrong, washing out in a loose corner, getting bucked off the bike in chunk MIPS and similar technologies represent genuine protection improvements.
I resisted this for longer than I should have. Early MIPS implementations felt bulky, and I convinced myself the weight penalty wasn’t worth it. Then I saw the Virginia Tech testing data. Their lab runs standardized impact tests across dozens of helmets and assigns star ratings based on concussion risk. The difference between a two-star helmet and a five-star helmet isn’t marketing it’s measurable reduction in brain injury probability. That data changed my mind.
The Weight Question, Honestly
I won’t pretend weight doesn’t matter. It does. But the margin where it matters is narrower than I once believed.
The contemporary helmet market spans roughly 340 grams for the lightest trail designs up to 400+ grams for models with extended coverage. Full-face helmets start around 750 grams for enduro-focused designs and climb past a kilogram for dedicated downhill lids. Those numbers matter if you’re comparing a half-shell to a full-face. But within the half-shell category? The difference between 340 and 380 grams forty grams, less than two standard gel packets is nearly imperceptible during riding.
I’ve tested this more rigorously than most people would consider sane. During a block of altitude training in Andorra last summer, I alternated between two helmets across similar rides: a 360-gram model with five-star Virginia Tech rating, and a 340-gram model that hadn’t been independently tested. Same routes, similar conditions, power data logged throughout. I could not find a consistent performance difference. What I did notice was that the heavier helmet with better ventilation kept me more comfortable on long climbs, which probably mattered more for my actual output than the twenty-gram difference.
This doesn’t mean you should ignore weight entirely. On shorter, punchier courses think Albstadt with its repeated steep kicks every advantage compounds. But the hierarchy of importance, as I’ve come to understand it, puts protection first, ventilation second, fit third, and weight fourth. Not because weight is irrelevant, but because getting the first three wrong costs you more than a few grams will ever save.
Fit Systems and the Hours You’ll Actually Wear It
Here’s something that doesn’t show up in specifications: how a helmet feels after four hours.
I learned this the hard way during a stage race in Spain. By day three, a pressure point I’d barely noticed on day one had become all I could think about. In training, I regularly log rides of three to five hours. During stage races or training camps, I might be helmeted for six hours across a day. The best protection in the world doesn’t help if a pressure point makes you want to rip the helmet off your head at hour three.
Modern retention systems have improved dramatically. BOA dial systems allow micro-adjustment around the entire circumference, eliminating the old problem of over-tightening to prevent shifting. Magnetic Fidlock buckles let you clip and unclip one-handed a small thing, but one that matters when you’re adjusting at a feed zone or clipping your helmet to your bag before a cafe stop.
What I’ve learned to prioritize is trying helmets in person whenever possible. Published size ranges reflect nominal specifications, but head shapes vary. I wear medium in most brands, but I’ve found specific models where the medium runs small enough to create pressure points, or large enough that the helmet shifts during hard efforts. Online purchasing is convenient, but for something this important, fit verification matters.
One specific example: I tried a helmet last year that received universal praise for its protection ratings and ventilation. On paper, it was perfect for my needs. In practice, the retention system sat higher on my occipital bone than I’m used to, creating a dull ache that became intolerable after two hours. Another rider on my team wears that same helmet for every ride and loves it. Individual anatomy trumps specifications.
The Ventilation Tradeoff
That realization about weight didn’t come all at once. It evolved alongside another lesson: ventilation matters more than I’d credited.
Racing XCO at altitude Crans-Montana, the high sections of some Andorran courses present specific thermal challenges. You’re producing enormous power while breathing thinner air, and your ability to shed heat directly affects sustainable effort. A poorly ventilated helmet can push core temperature up faster than your body can compensate.
At sea level, humidity becomes the enemy. I’ve raced domestic events where the air felt like soup, and helmet ventilation mattered less than the ability to dump water over my head at feed zones.
Designs like the POC Cularis represent current thinking on ventilation, massive front scoops, strategic channeling, large rear exhaust ports. I’ve ridden similar designs and can confirm the sensation: even on cold mornings, you feel air moving across your scalp. Whether that translates to measurable performance gains is harder to verify, but I feel fresher in well-ventilated helmets during long hot efforts.
One thing I’ve changed my mind about: helmet color. I used to choose based on team colors. Now I run white whenever possible. The thermal difference in direct sunlight is noticeable. For a ninety-minute race, it’s an easy choice.
Protection Technologies Beyond MIPS
MIPS dominates the rotational protection conversation, but it’s not the only approach. WaveCel, Koroyd, KinetiCore, and newer systems like the Release Layer all manage rotational forces during oblique impacts.
I came around to this slowly. For a while, I dismissed anything that wasn’t MIPS as marketing. But after riding helmets using most of these technologies, my honest assessment is that implementation matters more than the specific technology on the box. A well-designed MIPS helmet outperforms a poorly-designed KinetiCore helmet, and vice versa. The Virginia Tech ratings confirm this meaningful variation exists within technology categories.
What I look for now is independent verification. Five-star ratings. Actual test data, not marketing claims. The brands that submit helmets for independent testing demonstrate confidence in their engineering. The brands that don’t make me wonder why.
KinetiCore deserves mention because it’s philosophically different. Rather than adding a slip layer, Lazer removes calculated sections of foam to create crumple zones that absorb shear forces. Whether this produces better outcomes is debatable, but I appreciate that it challenges the assumption there’s only one way to solve this problem.
Full-Face Considerations for XCO
Traditional XCO racing rarely requires full-face protection. The courses are technical, but consequences tend toward bruises and broken collarbones rather than facial impacts. I race in a half-shell and expect to continue doing so.
But.
Modern lightweight full-face designs have changed the conversation. Helmets like the Fox Proframe RS weigh around 750 grams barely 400 grams more than my current half-shell and offer chin protection that would have been unthinkable five years ago. For training on particularly technical terrain, or for personal riding at bike parks, that weight penalty buys meaningful protection.
I’ve started wearing a lightweight full-face for certain training sessions. Not for race simulation, but for sessions where I’m pushing limits on unfamiliar terrain. A broken jaw costs you a season. A slightly heavier helmet costs you nothing you can measure. The math is straightforward.
Convertible helmet designs with removable chin bars attempt to bridge this gap. I’ve tested several. My honest assessment is that they represent genuine compromises. The attachment mechanisms add complexity and potential failure points. The half-shell configurations lack the visual and mechanical refinement of dedicated designs. For riders who genuinely need both modes enduro racers, for instance convertibles make sense. For focused XCO racing, I’d rather own two purpose-built helmets than one that does both things adequately.
What Actually Happens When You Get It Wrong
I’ve been fortunate. One significant crash with a helmet that did its job. Numerous minor incidents that never tested my equipment seriously. But I’ve seen teammates and competitors get this wrong.
A rider I trained with briefly ran ultralight helmets exclusively. He prioritized weight above all else. During a training ride, he caught a pedal on a root, went over the bars, and landed on the side of his head. The helmet cracked through entirely. He walked away, but the doctors told him the margin was slim.
Another example: a rider who never replaced his helmet after crashes because nothing was visibly damaged. EPS foam is designed to compress and absorb energy once. After a significant impact, internal structure may be compromised even if the shell looks fine. He took a second crash on a helmet that had already done its job once. The outcome wasn’t catastrophic, but it was worse than it needed to be.
The stakes are real. Not abstract, not theoretical. Real consequences measured in recovery time, cognitive function, career interruption. I’ve accepted that being slightly conservative about head protection represents the correct risk calculation.
My Current Approach
I run a five-star Virginia Tech rated helmet with MIPS for all racing and most training. The specific model matters less than those criteria. When my sponsor releases new options, I check the independent ratings before committing. If a new helmet hasn’t been tested yet, I wait or ask questions.
For long training rides in hot conditions, I prioritize ventilation. For technical sessions on unfamiliar terrain, I consider a lightweight full-face. For racing, I trust the engineering and focus on other variables.
I replace helmets after any significant impact, regardless of visible damage. I replace them annually even without impacts, because materials degrade and adhesives weaken. The cost of a new helmet is trivial compared to the cost of compromised protection.
Fit verification happens before any new helmet enters rotation. I’ve learned the hard way that published specifications don’t capture individual anatomy. A helmet that reviews well and performs well in testing might still be wrong for my head. The only way to know is to wear it.
What I’m Still Figuring Out
Eight years in, and I don’t have this completely solved. Questions remain.
The relationship between helmet ventilation and actual thermoregulation during maximal effort isn’t well-established in the literature I’ve found. I believe better ventilation helps, but quantifying that belief with data has proven difficult. Training partners with worse-ventilated helmets sometimes outperform me on hot days. Maybe helmet ventilation matters less than I think. Maybe their heat adaptation is superior. I’m not certain.
The long-term cognitive effects of subconcussive impacts the accumulated small jolts over years of racing represent another uncertainty. Current helmet technology focuses on preventing concussions. Whether it adequately addresses lower-level repeated impacts is unclear. I hope the science clarifies this. In the meantime, I err toward more protection rather than less.
Individual variation in what constitutes a good fit remains frustrating. I wish there were better tools for matching head shapes to helmet designs without physically trying dozens of options. Maybe 3D scanning and virtual fitting will solve this eventually. For now, I budget time for in-person testing whenever I’m considering equipment changes.
The Deeper Lesson
That crash at Leogang taught me something beyond helmet selection. It taught me that the things we assume are optimized might not be optimized for the right variables.
I had been optimizing for weight because weight was easy to measure. Grams on a scale. Simple. But protection, fit, ventilation these are harder to quantify, so I gave them less attention. That asymmetry wasn’t rational. It was just convenient.
Now I try to ask harder questions about all my equipment choices. Not just “what does this weigh?” but “what does this actually do when things go wrong?” The helmet question clarified a broader approach: take protection seriously, verify claims with independent data, accept small disadvantages in pursuit of meaningful safety margins, and remain willing to change your mind when evidence warrants it.
The foam and plastic between your skull and the rock garden isn’t glamorous equipment. It doesn’t make you faster. It doesn’t improve your power numbers or sharpen your handling. It just does one thing: it keeps you racing. When you frame it that way, the choice becomes clearer than marketing would suggest.
I still crash sometimes. Everyone does. But I crash with confidence that the equipment on my head represents careful consideration rather than default acceptance. That distinction matters more than I once understood.