Troy Lee Designs Flowline SE MIPS Review

Troy Lee Designs is no stranger to helmet manufacturing, they produce a wide variety of protection for both motocross and mountain biking. Complimenting a full line of full-face and half-shell mountain bike helmets, the Flowline SE is a mid-range trail riding half-shell that boasts some stellar safety certifications and creative features. Notably, this helmet carries an NTA-8776 Certification for use on e-bikes as a result of its dual-density EPS foam core. The inside of the helmet features the quick-adjust MIPS B-Series Rotational Impact Brain Protection System and an anti-microbial, quick dry liner. Cool features like a 3-way adjustable visor and a Flidlock magnetic buckle make it feel full-featured and high quality.

With an abundance of features, it scores well against our lineup of the best helmets on the market. We generally liked the comfort and performance of the helmet but felt like its bulk and warmth wouldn't make it a first choice for daily trail rides. Ultimately, it was bested by better ventilated competitors, but we'd still recommend it, especially for someone wanting that little bit of extra protection for e-bike speeds.

Performance Comparison

Protection

The Troy Lee Flowline offers a high level of protection by combining extended coverage, an adjustable MIPS B-Series liner, and dual-density EPS foam designed for low and high-speed impacts. The rear half of the helmet drops low for a relatively deep fit providing good coverage toward the bottom of the skull.

It's not the most coverage we've seen on a half shell but is above average amongst our test helmets. The full wrap in mold construction has only 14 vents resulting in more of your skull being covered by foam than vents.

The expanded polystyrene foam in the Flowline SE is dual-density, featuring a softer EPS foam on the inside and a harder EPS foam next to the shell. Supposedly this works to manage impact energy at both low and high speeds. This was a feature that we, fortunately, didn't test but according to the NTA which is a Dutch safety standard for e-bike helmets, this helmet is certified for use on e-bikes where crash speeds are typically higher. The helmet also boasts a 5-star safety rating from Virginia Tech's Helmet Safety Rating Lab.

The Flowline SE features a next-generation MIPS liner that protects against the forces of rotational impacts. The B-Series liner moves a little more than we're accustomed to even when secured with the boa-style retention system in the lowest setting around the bottom of the occipital ridge. While we're glad to have the extra layer of protection, we found the external movement of the helmet a little distracting on occasion.

While we consider this an extra coverage half shell, it has nowhere near the coverage of the Fox Dropframe or the Giro Tyrant. Those 3/4 shell helmets provide far more coverage at the temporal lobe and beyond. The Flowline SE gets its extra level of protection from the dual-density foam which may benefit you in higher-speed collisions but only in the coverage zones.

Comfort

We were generally impressed with the overall comfort of the Flowline SE. The antimicrobial padding is supple and lines most of the MIPS liner. The fit of the helmet is deep and somewhat round giving more space on the sides than we experienced fore or aft. It's available in three sizes, but there is no overlap in sizing so some users on the cusp of sizes may feel like they're asking a lot of the internal retention system.

As with many other helmets, the Flowline SE has a fit retention system used to snug and secure the helmet on your head. It is tightened or loosened by a large glove-friendly knob at the back of the helmet that controls the harness. That harness can be adjusted up or down to three separate positions to customize the fit.

The straps of the Flowline SE sit flat and contribute to the comfort of this helmet. They are secured under the chin with a fidlock magnetic buckle that is particularly friendly to gloved digits. The chin strap attaches to a pentagonal-shaped plastic yoke under the ears that splits the webbing and does a great job of keeping the straps flat. The strap splitter design is becoming more common on higher-end helmets and is far more comfortable and less bulky than other configurations.

Ventilation

With substantial coverage and just 14 vents, the Flowline SE isn't huge on airflow. While we weren't impressed with its ventilation, the helmet stayed comfortable throughout our long rides and we found the padding to be impressively absorbent.

It has six vents on the front half of the helmet that act as an intake as you ride, including two eyebrow-sized vents on the forehead. The top of the helmet has two medium-sized vents that also work to draw air in. The vents on this helmet aren't inadequate but the inner channels where air moves toward the rear exhaust vents are narrow and shallow resulting in minimal airflow.

The helmet exemplifies a tradeoff between coverage and ventilation and perhaps e-bikers looking for extra protection at higher speeds can sacrifice a bit of airflow. Additionally, the case could be made that e-bikers aren't generating as much heat with their battery-assisted rides and don't need the same cooling capacity as those powering their bikes themselves.

Features

Beyond the features previously covered in the protection and comfort sections, the Flowline SE has a 3-position adjustable and screw-less visor. Eyewear integration doesn't appear to have been planned with this helmet but we were able to store some of our riding glasses in the vents above the temples. Glasses with curved earpieces didn't hold securely while those with straighter arms stowed without too much play.

The rear of the helmet has a relief that can be used for goggle straps but if finding a goggle-compatible helmet is your aim, you can do better with a helmet that's actually designed for goggle use. The adjustable visor, which attaches without screws moves up in 3 positions for about two inches of total range.

Weight

At 429 grams or 15.13 ounces for our tested XL the Flowline SE is on the higher end of the weight spectrum for half shells. The weight isn't a surprise looking at its coverage but we noticed a bit more movement on our heads while riding the bumpiest of trails, even with the retention system at full grip, that could be due to its weight.

Durability

Durability isn't an issue with the Flowline SE. We used this helmet on more than a dozen rides, had it bang around the back of the truck a few times, and encountered quite a bit of adverse weather but it looks no worse for wear. The straps are visibly dirty, and there's some mud in hard-to-reach places but it still looks great. The rigid full-wrap in-mold polycarbonate shell isn't prone to denting and it really does cover the EPS foam everywhere but inside of the vent holes. The fit adjustment system had no issues and the MIPS liner slides just as freely as it did on day one. All Troy Lee Designs Bike Helmets carry a 3-year warranty.

Should you buy the Troy Lee Designs Flowline SE

While certainly not cheap, the Flowline SE feels like a good value and it packs in some deluxe features. If you're prioritizing safety and coverage over airflow, especially for use on an e-bike this helmet is an excellent choice. It's comfortable, offers excellent protection, and has user-friendly features. While not enthused about the airflow it provides or the lack of eyewear integration, we had no major gripes with this helmet and if it represents a higher level of safety, we'll be pleased to see it on more heads. We feel like the helmet is a solid product for e-bikers and its coverage and durability outweigh the faults.

What other mountain bike helmets should you consider

Those wanting similar protection at a lower price point might want to check out the Flowline for $120, it has all of the safety features as the Flowline SE but sacrifices the nice liner and magnetic buckle. Oddly the cheaper version of this helmet scores better in the Virginia Tech Helmet Safety Lab safety ratings. Should you do most of your riding in hot climates or push yourself flat out on the e-bike you might appreciate a bit more ventilation as we find in the Poc Kortal Race MIPS.