Trail and enduro bikes are lighter and faster than ever. They climb like cross-country race bikes used to, and offer enough suspension performance and confidence-inspiring geometry to produce break-neck speeds, literally. Troy Lee Designs, who has offered the incredibly popular A1 trail helmet since 2013, saw a need to up the ante when it came to protection to keep the heads of those aggressive trail riders safe. The new iteration of the A1 is the result, complete with features that not only absorb catastrophic impacts but also reduce the risk of concussion from all impacts, whether direct or rotational.

Tech features:

The A1 is designed to look great and protect riders in all trail-riding situations. It features a polycarbonate shell with impact-absorbing EPS foam and a large visor with 1 inch of vertical adjustment. New for this generation of A1 helmets is the MIPS system, which features an inner liner that’s designed to allow the head a bit of movement in the event of a crash. This extremely thin bit of yellow material keeps the head from jerking violently in a crash and is said to improve concussion protection in both high- and low-speed impacts.

To keep riders cool, the A1 uses 16 vents in all: six intake, six exhaust and four directional. Specially designed passages in the shell allow incoming air from the vents in the front to flow across your head, and the inner liner is made with “nanowick” material. The helmet’s snugness can be fine-tuned with a multiple-position, cam-lock-adjustable rear stabilizer, and the thin, nylon retention straps are fastened by a contoured snap buckle.

Special touches include anodized aluminum hardware and a breathable helmet bag. Our size-large test helmet weighed 393 grams and retails for $215 in several color options. The A1 MIPS is also available with the same features with less fancy paint schemes. This version is called the Drone. It weighs the same and retails for $189 without the helmet bag.

Field test results:

The A1 helmet offers more protection than a cross-country lid and less protection than a full-face DH lid. When it was first introduced three years ago, it was one of the only enduro-specific helmets out there. Now, there are many more of these 3/4 helmets to choose from. The new A1 offers more protection than the original A1, because it includes protection for low-speed and rotational impacts with a MIPS system.

The TLD A1 helmet fits most riders like a glove with a shape that’s neither too round nor too narrow. The retention system works perfectly, and the straps and snap are very comfortable, so there’s no need for a break-in period. The rear stabilizer dial is easy to use, even on the fly, and keeps the helmet from rocking or shifting when you’re charging a rock garden or heading down a steep chute. The liner’s padding is very comfortable and wicks moisture better than most. The A1 features extra coverage, and that doesn’t necessarily mean it turns into an oven on the trail; however, it isn’t the coolest or best-ventilated helmet we’ve tried. Troy Lee pushed the designers to maximize ventilation while still meeting the desired safety standards, and the result is a well-designed system that combines open vents with channels molded into the shell that pull air through the helmet. Considering the helmet’s protection and coverage, it’s on par with most other enduro helmets in its class.

The MIPS system is a welcome addition to the helmet, offering better protection in more crash situations. The MIPS system is deceptively simple, with a thin layer of yellow plastic material surrounding the liner of the helmet. This provides a low-friction connection between your head and the inside of the helmet and allows precious millimeters of movement that keep your skull from being violently shaken. Don’t think of it as additional padding, because it’s not. It’s designed to prevent the violent rotation on impact that can cause concussions in even low-speed crashes—the ones that standard EPS foam helmets do little to protect against. The execution of the A1 MIPS version works well and does not affect ventilation or overall comfort. It does, however, affect the sizing, so if you were between sizes with the original A1, you may have to go up to the next shell size. While we didn’t have the chance to put the MIPS system to the ultimate “crash test,” we can say that we felt more secure knowing it was there if we needed it.

The A1 helmet has seen tremendous success, partially thanks to the success of TLD’s full-face helmets, but also thanks to the nice execution of a true enduro or all-mountain 3/4 lid. The A1 is comfortable and stylish and now offers the added protection of a MIPS liner for extra peace of mind. The helmet isn’t compatible with many riding glasses, but most A1 riders will probably prefer the full-enduro goggle anyway. Bottom line: this is a top-notch helmet designed to work for trail riders of all kinds.

THERE ARE SO MANY WAYS TO GET MOUNTAIN BIKE ACTION