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

Since a helmet's main role is to protect its wearer, we gave this metric 30% of the total score of the Manifest. We examined this metric by partnering with the ACT Lab and conducting impact tests in a controlled environment, ultimately performing two drops: one from 2.3 meters on one side of the helmet, and one from 1.0 meters on the other side. We collected data from g sensors integrated into a fake head.

Slow Impact Test Results

When dropped from 1 meter, the Manifest performed pretty good, but not as well as the highest scoring Lazer Coyote Kinecticore. In the graph below, the higher the line in the graph, the more -g-forces and the lower the score.

Fast Impact Test Results

Finally, we distilled our findings into a more digestible rating from 1-10. This helmet came in about average in the lineup.

With a score of 6.5, this helmet did fairly well in the impact test metric, and it also passed the requisite standards set by the CPSC, which is required of all helmets sold in the US.

We also investigated other aspects of each helmet's protection, though we didn't include those findings in this metric's score. The Manifest's Mips Spherical 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 EPS foam liners connected by small elastomers that make up the Mips Spherical 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. The two shells have varying EPS foam densities to protect from both high and low-speed impacts. This system eliminates the need for the plastic interior liner found on most Mips-equipped helmets, and according to Giro, is scientifically proven to reduce rotational motion from angled impacts. In addition to the rotational impact protection, the Manifest Spherical offers above-average head coverage and a secure fit.

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 EPS liner contours nicely to a wide variety of head shapes without creating pressure points. Over the course of testing, we had a number of different riders try out this helmet, and nobody 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 EPS 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 EPS 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 gave useability 15% of the total score of the Manifest. 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 EPS 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 EPS 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 are 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.

Weight

We gave this metric 15% of the total score of the Manifest, simply weighing it on a scale and making comparisons to the rest of the lineup. This helmet came in towards the top.

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.

What Other Mountain Bike Helmets Should You Consider?

If you're looking to save some coin without sacrificing too much performance the Fox Speedframe Pro or Specialized Ambush 2 are great options that compete with the Manifest. If you're looking for a top tier budget option, the Lazer Coyote Kineticore boasts excellent scores for half the price.