Jetstream TT Helmet

What Our Gearhead® Experts Are Saying:

"I've raced the Jetstream TT across both dedicated time trials and triathlon bike legs, and the dual protection stack of MIPS and Koroyd sets it apart from aero lids that treat safety as an afterthought. The VaporFit adjustment holds the helmet in place through aggressive position changes, and five vents do a better job managing heat than you'd expect from a helmet this aerodynamically focused. The magnetic visor system is genuinely fast in a transition context, and the ChromaPop lens makes a noticeable difference in contrast and depth perception on technical descents."

Time trial and triathlon racing demand a helmet that can operate at both extremes of the performance equation — aerodynamically optimized for speed and structurally engineered for the kind of protection that matters when something goes wrong at race pace. The Smith Jetstream TT Helmet is built to hold both of those requirements without trading one for the other. Smith has spent years refining helmet construction around real-world impact science, and the Jetstream TT applies that development directly to the demands of the clock-racing disciplines.

At the core of the protection system is a polycarbonate shell paired with a Koroyd liner, a co-polymer welded tube structure that absorbs and disperses impact energy more efficiently than traditional EPS foam by collapsing in a controlled manner on contact. That foundation is reinforced by a MIPS layer — the Multi-directional Impact Protection System — which allows the helmet to rotate slightly relative to the head during an angled impact, reducing the rotational forces transmitted to the brain. Together, MIPS and Koroyd create a layered protection stack that delivers meaningful safety performance without requiring the bulk that typically comes with high-impact resistance. The polycarbonate shell keeps the overall weight to 410 grams in a large, a competitive figure for a helmet carrying this level of protective technology.

The aerodynamic profile is supported by a low-profile y-strap divider that minimizes drag while maintaining structural positioning, and five ventilation ports are placed to generate airflow across the head during high-output efforts — a balance point that addresses the heat management challenge inherent in closed aero helmets. The VaporFit adjustment system provides 270-degree wrap-around fit tuning, allowing riders to dial in a secure, stable fit that holds through position changes between the aero tuck and standing efforts. An ionic anti-odor lining manages moisture and freshness across long training blocks and multi-day race weeks. The magnetic visor attachment system accepts both included lenses — a standard clear shield and a ChromaPop performance lens — with a tool-free swap that works cleanly in a triathlon transition context or between morning and midday start windows. ChromaPop lens technology enhances color contrast and visual definition, which adds meaningful depth perception on fast descents where reading the road surface quickly matters. The Jetstream TT meets U.S. CPSC and EN1078 certification standards and is backed by a limited three-year helmet warranty.