Smith Mainline MIPS Review
Compare prices at 4 resellers Pros: Breathable, more robust than other enduro-focused options, lightweight
Cons: Not suited for frequent bike park duties, a little expensive
Compare Similar Products
Our Analysis and Test Results
Smith has a long-running history of producing quality mountain bike helmets. Until recently, they did not have a full-face offering in their lineup. The Mainline is their first entry into this realm and they hit a home run. This helmet delivers high levels of comfort and ventilation and offers a nice level of protection that should suit most riders and applications.
If there is one area where the Mainline really stands out, it is comfort. We found this helmet to be supremely comfortable and we are confident calling it the most comfortable full face in this review.
We felt the out-of-the-box fit of the Mainline was pretty dialed. The fit of our large test helmet was more or less true to size. If you are on the cusp of sizes, we would recommend trying one on before you buy and potentially sizing up. After sweating into this helmet for hours on end, the pads don't seem to be compacting or packing out. Smith includes additional pads in the box that allow you to fine-tune your fit if needed. We didn't find pad adjustments to be necessary for our testers with large heads.
When wearing this helmet, we found the ear pockets to be well executed. There is plenty of room for your ears and they are not being pressured into the side of your head. The cheek pads have a secure fit without too much pressure or any discomfort. The crown of the helmet fits smoothly against the top of the head. We won't harp on this superb fit too much as every head is different and certain users may have slightly different opinions on fit. One area of concern could be in front of the helmet above the brow. If there was one area where we could see there being a pressure point, it's right there.
The Mainline is comfortable to wear and we had no problems leaving it on while hiking up freeride lines, sessioning a chute, or even pedaling for extended periods. This is not the helmet you will be dying to take off immediately at the end of each run. Given its intended application of enduro racing, the manufacturer expects riders will be wearing this helmet for significant amounts of time throughout a race day. As a result, comfort is important, and we feel that Smith nailed it.
The Mainline posted a solid score in the protection metric. Among enduro-focused helmets, this was our favorite. It feels significantly more robust than some of the super-light options, and we feel is an excellent blend of weight and protection. The additional ounces that the Mainline has compared to other similar options helps give it a more substantial feel and made us more confident at high speeds or in the gnar.
The Mainline is DH certified and carries CPSC CE EN 178 and ASTM F1952 certifications. This helmet uses Smith's Aerocore technology which they claim to be the best blend of weight and protection. This uses a thinner shell paired with the Koroyd honeycomb material which they claim provides superior energy absorption while still allowing air to pass through. Coverage felt great, and we didn't feel like any part of our head was exposed.
This helmet also features the MIPS system. MIPS stands for Multi-directional Impact Protection System. This is a yellow and gray layer of what looks like plastic under the padding of the helmet. This is a slip layer that allows the helmet to rotate slightly in the event of an angled impact and is claimed to reduce the rotational forces that reach the rider's brain. It also features a D-ring strap for additional security in the event of a crash. Sure, the D-ring isn't quite as quick to use as a plastic buckle, but we feel it adds to this helmet's protection.
The Mainline in the size Large we tested weighs 27-ounces. At this weight, this helmet is on the heavier side of the spectrum for enduro-focused helmets. That said, it is still a very lightweight helmet and we are only talking about a couple of ounces between these helmets. The tradeoff is that it has a more substantial and robust feel, comparatively speaking.
Ventilation is quite impressive with the Mainline. It has 21 vents that allow air in and out of the helmet. All of the vents on the front, top, and back of the head have Koroyd beneath them. Koroyd is a porous, honeycomb-like material that provides coverage and impact protection while still allowing air to pass through. Between the outer shell and Koroyd are channels that allow air to flow from front to back. Three intake vents are located on the front of the helmet where cool air flows in. There are also several vents on the top and back of the head where warm air is allowed to escape.
The chin bar has five large, open vents, to allow for great airflow when you are standing up and hammering on the pedals. These chin bar ports aren't quite as gigantic as some of the enduro-focused helmets. That said, they are wide open and air flows freely through them to the mouth and chin.
On the trail, we found the ventilation to be excellent. We climbed, hiked, and shredded this helmet and firmly believe it has top-notch airflow. On cooler days, there is no reason to take this helmet off to climb back up the hill. You can really feel the air passing through the helmet and the open chin bar allows plenty of air to reach the rider. This is a breathable helmet and you can get away with leaving it on for quick climbs, but it is still a full-face. It is never going to offer comparable ventilation to an open-face helmet.
The Mainline has an adjustable visor and is a perfect size. It isn't too long or too narrow. The end of the visor is approximately 6.75-inches wide. The visor is adjustable. A center thumbscrew loosens the visor which has a relatively narrow range of adjustment. It can be moved up and down approximately one inch.
This helmet works well with goggles and could be used with sunglasses as well. Some enduro-style riders like to store the goggles above the brow of the helmet when climbing. The small adjustment range of Mainline's visor doesn't accommodate this sort of move. Riders will need to store their goggle around their neck or turn them around backward on the helmet to store them when not in use.
Throughout our testing process, we observed no signs of abnormal wear and tear on our Mainline helmet. The quality of craftsmanship appears to be excellent, and we have no serious concerns about durability. The shell, foam, and Koroyd are all in excellent condition, and the padding looks as good as the day we got the helmet aside from a few sweat stains. The thumbscrew and side mounting screws on the visor are still tight and holding strong.
The Mainline comes with a drawstring helmet bag and extra pads. The extra pads are different sizes than the ones that come stock in the helmet and allow you to fine-tune the fit as needed.
We feel the Mainline is a good value. Yes, it is a little more expensive than some of the other enduro-oriented full-face helmets, but we feel that the quality and comfort level helps justify the price tag. We also feel that the Mainline is practical in a huge number of situations which enhances its value.
The Smith Mainline helmet combines a lightweight shell with excellent breathability and a protective feel. Outside of true enduro racing, this helmet should work well in a ton of situations including pedal-y shuttles and gnarly hike-a-bike trails. Yes, it is a little pricey, but we feel the design, build, and overall quality justifies the cost, and we feel this is an excellent option for the rider seeking a well-ventilated full-face.
— Pat Donahue
Ad-free. Influence-free. Powered by Testing.
GearLab is commited to honest, objective, reviews. Our experts test thousands of products each year. We buy all the products ourselves. We won't accept manufacturer's freebies. No ads. No "sponsored" content. Just real, honest, side-by-side testing.Learn More