Mainline Mips Full-Face Helmet

What Our Gearhead® Experts Are Saying:

"I've raced the Mainline MIPS on full enduro stages and dedicated downhill runs, and it's the first full-face I've used where the ventilation genuinely removes the temptation to swap to a half-shell on hot days. The Koroyd crumple zones add a layer of impact management that goes beyond what standard EPS foam delivers, and combined with MIPS the protection stack here is serious for a helmet at this weight. The modular fit system is worth taking time to set up properly — getting the right cheek pad and crown liner combination makes a meaningful difference in how securely the helmet sits under load."

Full-face helmets have historically demanded a compromise: accept the heat and weight in exchange for the coverage, or reach for a lighter lid and accept the reduced protection. The Smith Mainline MIPS Full-Face Helmet is Smith's answer to that compromise — a helmet engineered from the ground up to deliver ASTM-certified downhill protection in a construction light and ventilated enough to wear through a full enduro race day without becoming the reason you slow down. Smith has spent years developing Koroyd technology across their helmet lineup, and the Mainline MIPS represents the most aggressive application of that system in a gravity-focused full-face.

The shell uses Aerocore in-mold polycarbonate construction with integrated Koroyd crumple zones — a co-polymer welded tube structure that collapses in a controlled manner on impact to absorb and disperse force more efficiently than traditional EPS foam alone. This architecture allows Smith to meet the demanding ASTM F1952-15 downhill certification standard at a claimed weight of 1 pound 15.6 ounces in a large, a figure that sits well below most helmets at comparable protection ratings. A MIPS layer adds the rotational and oblique impact management that addresses the angled crash mechanics most associated with serious head injury, rounding out a protection stack that operates at multiple levels simultaneously.

Thermal management is handled by the AirEvac ventilation system, which channels airflow through 21 ports distributed across the helmet to create consistent through-flow during both high-speed descents and slower uphill efforts. The result is a full-face that breathes at a level typically associated with half-shell designs, removing the comfort penalty that has historically made full-face helmets a reluctant choice for warm-weather enduro riding. An adjustable visor adds versatility across varying light and trail conditions. The fit system is genuinely modular — three cheek pad sizes, two crown liner sizes, and two neck roll sizes allow the interior to be configured precisely to the rider's head geometry rather than relying on shell size alone for fit. Anti-odor removable and washable pads support long seasons of use without degrading comfort. The D-ring chin strap closure keeps the fastener lightweight and reliable under load. As with all Smith helmets, the Mainline MIPS carries a limited three-year warranty, and the helmet runs small — sizing up from a standard helmet size is strongly recommended for the best fit and most accurate protection positioning.