All New 6D Alterra Helmet

6D launches a new lightweight, full face, enduro helmet today called the Alterra. We don't see a ton of 6D helmets around here, so let's first chat about the company. 6D, a company that only makes helmets, and only for two-wheeled applications, started with motocross in 2011. The name 6D comes from 6 degrees of freedom in the movement of the helmet relative to the head; hence, all helmets have a ball-and-socket two-layer design. 6D calls this Omni-Directional Suspension™ (ODS). 6D's focus is the best possible protection, even if it means the helmet is heavier and bulkier. I had a great chat with some of the 6D folks before this launch. They were fairly honest that they weren't willing to sacrifice on the protection standards they'd developed in the moto world, meaning their mountain bike helmets to date were a bit heavy, a bit bulky and a bit hot. The new Alterra helmet is intended to fix all that, so 6D can expand more into mountain biking.

Tech and Development

6D claims this new Alterra is the best bike helmet they've made. Helmet technology is still the priority, with the heart of the Alterra being the ODS System. 6D claims ODS reduces energy transfer to the brain over a wider range of energy demands, including low, mid, and high velocity impacts for both linear and angular acceleration. This is achieved through the use of a suspended dual-liner assembly that can displace and shear in any direction upon impact. 6D claims the system has been rigorously tested and proven to offer superior impact mitigation across multiple disciplines. Through constant evolution and rigorous development, they've got the weight down, the size down, and the styling down to where they think they have a competitive light-weight, enduro, full-face helmet.

Key Features:

• Patented Omni-Directional Suspension™ (ODS): Enhances impact force mitigation for both linear and angular accelerations.
• In-Molded Carbon Fiber Chin bar and Internal Roll Cage: Adds structural integrity while maintaining a low weight.
• Polycarbonate Shell: Ensures durability and impact resistance.
• Multi-Impact EPP Inner Liner and EPS Outer Liner: Provides layered protection.
• EPP Sternum and Clavicle Crash Pads: Offers additional safety features.
• lonic+ Antibacterial Comfort Liner: Maximizes airflow and maintains hygiene.
• Goggle Compatible with Under-Visor Storage: Adds convenience and versatility.
• Glasses Compatible: Accommodates riders who wear glasses.
• Directional Venting and Sub-Channeling: Optimizes airflow for enhanced cooling.
• Extra-Large Rear Directional Exhaust Vents: Ensures efficient heat dissipation.
• Large Over-Brow Ventilation Channels: Promotes airflow to keep the rider cool.
• Fidlock Closure System: Provides secure and easy fastening.
• 3-Position Snap-Away Adjustable Visor: Allows for a customizable fit.
• Travel Bag Included: For easy transport and storage.
• Multiple Comfort Liners and Pad Sets: Customizable fit options for all riders.
• 710g M/L
• MSRP: $395 USD / ~$560 CDN

Alterra Fit

I have been riding the Alterra for a couple of weeks. The helmet comes with a large array of foam pads in different thicknesses so you can tailor the fit. That said the M/L Alterra fit my 57 cm head perfectly out of the box. There is ample space around the ears, giving the Alterra an airy feel. There is good space to the chin bar, with excellent venting. The only weird thing related to fit was that the chin strap ever so slightly touched my ear due to the profile of the cheek pad. I only noticed this when checking the helmet fit at home and I didn't notice this at all while riding.

On The Trail

I've done two bigger rides in the Alterra so far. One was a shuttle / pedal day with over 800 m vertical climbing on a glorious 19°C spring day in the sun. Even though it was humid and relatively warm, I stayed comfortable in the Alterra. On some of the steeper, slower climbs, the Alterra felt hotter than an open-face helmet, but even one or two gears down on the cassette it was surprisingly cool. I liked the adjustable visor and ample parking space for my goggles.

I like descending in full-face helmets and goggles (maybe it's from the DH racing roots). I like the extra protection from the chin bar, and I appreciate how goggles don't bounce around on my face. I liked the field of view, and the goggle fit was excellent. Some MIPS / two-layer helmets can have a squeak when riding, or feel jiggly, but the Alterra felt stable and secure with no noises. I love the Fidloc chin strap, making removing and putting the helmet on as easy as possible.

Verdict

This is the best ventilated full-face helmet I've tried, and certainly a helmet I'll take on more rides where I want more protection than an open-face helmet. When descending, the Alterra melted away from my head, and that's about the best compliment I can give. While the 395 USD asking price is on the upper end of full-face helmets I do think it's fairly priced. Squeezing an ASTM F1952 DH certification into a two-layer helmet at 710 grams has taken some serious tech to pull off. Beyond that, the fit and finish of the Alterra is premium and comparable to the similarly priced Leatt Gravity 6.0 I reviewed last year. I'm impressed so far, and looking forward to spending more time in the Alterra this summer.

6d Helmets