Seven years after entering the mountain bike helmet market, Smith have finally added a full-face option to their lineup. The Mainline is aimed at enduro racers and riders in search of a lightweight, DH certified full-face with enough ventilation to keep it from becoming uncomfortably hot while climbing.
Smith worked closely with their athletes during the development process to create a helmet that met the criteria on their wish list, which included protection, a comfortable fit, good airflow, and goggle compatibility, all reasonable requests for a high-end helmet like this.
There are two additional color options other than the black version shown here; a sage/red, and the green color used by the Rocky Mountain enduro team. The Mainline is available in sizes S, M, and L, and retails for $300.
Smith Mainline Details
• Weight: 802 grams (medium)
• 21 vents
• Koroyd impact protection panels
• MIPS liner
• Sizes: S, M, L
• Colors: black, sage / red, green
• CPSC, CE EN1078 and ASTM F1952 DH certified
• MSRP: $300 USD
My head measures 58cm, which puts me smack dab in the middle of the 57 – 59cm range that Smith recommends for a medium helmet. There's no twist-dial retention system in the Mainline, but three thickness of cheek pads, two thicknesses of neck pads, and two different crown liners are included. It's worth taking the time to experiment with different combination to ensure the best fit. When I tried the helmet on right out of the box it didn't feel all that comfortable, but within 10 minutes I'd found a pad set up that greatly improved the fit.
I ended up using the thinnest check and neck pads, and the thicker of the two crown liners. I'd put the overall comfort level in between the Troy Lee Stage helmet and the Fox Proframe. The Stage is the best fit for my head shape, while the Proframe is a little tight at my forehead. Of course, helmet fit will vary from rider to rider, but these points might be useful if you have a more oval-shaped head like mine.VENTILATION
One of the key features I look for in a lightweight full-face is how well the chinguard breathes. Most enduro races have at least some climbing in them, and the last thing you want is to to feel all the hot air you're expelling get blown back into your face. The chinbar opening on the Mainline is well placed, and I didn't experience any goggle fogging or stale air recirculation. It's also wide enough to spit through, a feature that comes in handy surprisingly often during a race or hard effort.
As far as overall ventilation goes, the Mainline does a decent job, although the Koroyd doesn't allow as much airflow as a completely unobstructed opening would. That can make things a little steamier on slow, humid climbs, but at speeds faster than crawl I was quite comfortable.WEIGHT
My size medium weighed in at 802 grams, a touch more than the 770 gram claimed weight. The TLD Stage and the Fox Proframe are both lighter at 711 and 756 grams respectively, but the Mainline is lighter than the 887 gram Bell Super DH and the 852 gram Leatt DBX 4.0. In other words, it's not the absolute lightest out there, but it's still a very reasonable weight for this type of helmet.
On the trail, it feels reassuringly solid without being heavy – I don't have any weight-related complaints. SAFETY
Smith were one of the first companies to use Koroyd as a form of impact protection in their helmets, and that material is present in the Mainline as well. Koroyd looks like a bunch of plastic straws that have been trimmed and glued together, and it's designed to crumple during an impact to help reduce the force that's transferred to a rider's head.
Koroyd isn't the sole material providing impact protection in the Mainline, though; the bulk of the helmet is still EPS foam, with a polycarbonate shell over the top of it. There's also a MIPS liner, which is designed to help reduce the force from rotational impacts. The Mainline is CPSC, CE EN1078 and ASTM F1952 DH certified PRICE
The Mainline's $300 price tag is right in the ballpark for this style of helmet. For comparison, a Bell Super DH helmet is $300, the TLD Stage is $295, and the Fox Proframe is $250 USD.
A variety of pad sizes are included so riders can achieve their ideal fit.ADDITIONAL FEATURES
Other features include a D-ring chin strap closure, and an adjustable visor. Along with the previously mentioned assortment of pads for adjusting the fit, the Mainline also comes with a cloth drawstring sack.
The Mainline is designed to work well with goggles, which makes sense given Smith's extensive eyewear collection. There weren't any fit issues with the Smith Squad XL goggles I used, which are on the larger side of the spectrum.ISSUES
Just like with the TLD D4 I recently reviewed, the MIPS liner in the Mainline can make a distracting creaking noise as it rubs against the inner portion of the helmet. This was more noticeable when climbing – once I put my goggles on to descend the the helmet rotated a little less on my head, and the noise subsided slightly. Humidity and head shape can play a role in how much noise MIPS makes, but still, I wish it was quieter. There are other versions of MIPS out there that have a soft fabric sticker between the plastic liner and the foam – perhaps that could be the ticket to quieting down future versions of the Mainline.
Comfortable, customizable fit +
Very reasonable weight