Giro Manifest Spherical Review

Since their inception, Giro has been at the leading edge of helmet technology, and the Manifest Spherical — with its dual-shell rotational impact protection — represents their latest innovation. While the designers at Giro have used the Mips Spherical technology before in their ski and full-coverage mountain bike helmets like the Tyrant, the Manifest is their first crack at packing the tech into a lightweight half-shell trail helmet. After hours in the saddle wearing the Manifest, we think they did a mighty fine job with it. We immediately found a lot to like, and we really had to dig to find complaints with this model.

Impact Test

The Manifest Spherical performed reasonably well in this portion of our review and also met the requisite standards set by the official governing body, which are required of all helmets sold in the US.

Slow Impact Test Results

When dropped from a lower height, the Manifest performed decently, but nowhere near as well as the highest-scoring model. In the graph below, the higher the line in the graph, the more g-forces and the lower the score.

Fast Impact Test Results

For the fast impact test, where we dropped the dummy head wearing the helmet from a higher set height, the Manifest again scored okay, but far from as well as the top-scoring helmet in the pack.

The Manifest's rotational impact protection system is fairly unique among half-shell trail helmets. Like its beefier full-coverage sibling, the Giro Tyrant, the Manifest consists of two separate foam liners connected by small elastomers that make up the rotational impact system. The two shells are designed to rotate against each other in the event of an impact, with the goal of reducing rotational forces on the head. In addition to the rotational impact protection, the Manifest Spherical offers above-average head coverage and a secure fit.

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Comfort

As soon as we tried on the Manifest, we could tell that Giro put a lot of care into designing a comfortable helmet. Like most Giro helmets, the protective foam liner contours nicely to a wide variety of head shapes without creating pressure points. During testing, we had several riders try out this helmet, and none of them had any complaints about the shell shape. The shell's interior features padding that is fairly minimalist, but well-placed enough to make it feel like you're putting on a well-cushioned ski or snowboard helmet rather than a lightweight mountain bike helmet.

Like any high-end mountain bike helmet worth its salt, the Manifest also offers a ton of adjustability to allow a wide variety of head shapes and sizes to find a secure, comfortable fit. The Roc Loc Trail harness has a huge range of adjustment with tiny indexed positions for micro-adjustment. Tightening it down pulls tension around the entire circumference of your head rather than just pinching at the back. The result is a snug fit that doesn't irritate over the course of a long ride. The harness can also be adjusted vertically across three different rear mounting points molded into the shell. Simple, adjustable ear splitters keep the Manifest's straps flat against the side of your head, and the chin strap has a small rubber loop to keep excess strap from flapping around and distracting on the trail.

Ventilation

You know a helmet is well ventilated when even on a slow, hot, stifling climb, you can feel air moving across the top of your head, and that's exactly what we experienced with the Manifest. Nineteen external vents that lead to internal channels in the protective foam shell allow the wind to move through your hair and almost make it feel like you're not wearing a helmet at all at times. The ventilation was the first thing we noticed when we took this helmet out for a ride. It's one of the airiest helmets any of our testers have ever used— comparable to the 100% Altec that we tested.

When things inevitably got a little bit hot on long climbs, we found that the Manifest's internal padding does a good job of absorbing sweat and keeping it away from your eyes. We didn't have any issues with sweat running down the lenses of eyewear or stinging our eyes. We would absolutely recommend this helmet for anyone riding in a hot climate or spending long hours in the saddle.

Usability

We examined this metric by sizing up each option's features and ease of use over the course of several weeks. This option scored very well, coming in at the top.

Unlike some of the other Giro models that we tested that were a little light on features, the Manifest is loaded with little details to make your ride a little bit easier and more enjoyable. The exterior packs a fully-adjustable visor with a wide enough range of movement to allow goggles to sit on the front of the helmet while climbing. It's mounted to the outer shell with hex-head bolts that can be tightened down if you want to lock the visor in one position. There are textured rubber pads at the rear of the helmet to hold a goggle strap in place, along with similar grippers in the interior of the liner air channels to hold sunglasses in place on the top of the helmet. We found the eyewear grippers especially useful to avoid fogging up sunglasses lenses while huffing and puffing our way up the mountain.

The Manifest's interior holds the already-discussed Roc Loc Trail harness, airflow channels, along with antimicrobial padding that discourages bacteria growth and keeps the helmet smelling fresh. The padding is held in place by small velcro patches and can be removed easily for cleaning. The list of features is rounded out with a Fidlock magnetic chin buckle. These buckles are getting more and more popular on modern high-end mountain bike helmets, and we're quickly growing to like them. It's super easy to buckle and unbuckle the helmet once you're used to the system – you can even do it one-handed, and the top side of the buckle contours nicely to the underside of the chin for a little bit of extra comfort.

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Weight

Given the dual-shell design and ample weight-adding features, we were surprised that the Manifest is among the lighter helmets in the test.

When considering its scores in other metrics, this helmet outperforms its weight.

Should You Buy the Manifest Spherical?

We weren't sure what to expect from this dual-shell trail helmet, but the Manifest Spherical did not disappoint in our field test session. It came in at or near the top of almost all of our scoring metrics and edged out some fantastic helmets to become a tester favorite. Despite the high price, we would recommend this helmet to anyone looking for a daily driver for anything from lunchtime laps on the local trails to all-day backcountry epics, though you'll have to pay a pretty penny. The Manifest Spherical is a top-shelf helmet, and it comes at a top-shelf price. After countless hours on the trail, we think it's absolutely worth the money.

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