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Giro Manifest Spherical helmet review

All day comfort and protection

Our rating 
4.5 out of 5 star rating 4.5
GBP £250.00 RRP | USD $260.00 | EUR €260.00
Giro Manifest Spherical mountain biking helmet

Our review

A seriously expensive, but incredibly comfy trail helmet that offers superb venting, loads of safety tech and a host of well-considered features
Pros: Well vented; really comfy fit; decent coverage; great safety features; lots of well-considered, useful extras
Cons: Massive price hike over the Giro Tyrant, which uses the same safety tech
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By our estimates, Giro’s Manifest Spherical is the priciest trail helmet on the market. In fact, it’s bang on £100 more expensive than the popular Montaro, which was, up until the Manifest was released, Giro’s top-tier mountain bike helmet.


So why does it cost so much?

Giro Manifest Spherical helmet construction details

According to Giro, the Manifest isn’t just a really safe helmet, it’s one of the best vented too, even rivalling some of its top roadie helmets.

At the Manifest’s core is Giro’s Spherical Technology, which was designed in conjunction with MIPS (Multi-directional Impact Protection System). This isn’t new, though, we’ve already seen it used in Giro’s Aether road helmet and more recently its Tyrant MTB lid.

Giro describes this design as using a ball and socket construction, whereby the outer liner is able to rotate around the inner liner during a crash, redirecting the crash force away from the brain on angular impacts.

Unlike the Tyrant and Aether helmet, the Manifest’s outer liner doesn’t fully envelop the inner liner, leaving the sides of the inner liner exposed.

Then there’s the different EPS foam. Giro has used a less dense EPS on the inner shell that sits closest to your head because it’s better at dealing with low-speed impacts. The outer shell features a denser foam which is better suited to handling high-speed impacts.

There’s also the Aura Reinforcing Arch. This is an impact-resistant polycarbonate band that spans the width of the Manifest’s outer shell to bolster the helmet’s structural integrity.

Thanks in part to this, Giro was able to put some seriously large vents into the Manifest (along with some internal channelling) making it a claimed 7 per cent cooler than the Montaro MIPS helmet.

It’s worth noting that the Spherical design means there’s no need to include a regular MIPS liner under the padding, which is a big help when it comes to getting air moving over the top of your head.

Overall weight for my medium sample is 363g, which is lighter than both the Montaro MIPS and Troy Lee Designs A2 helmets.

Giro Manifest Spherical helmet features

As you’d expect for the money, there’s a host of other neat details too.

Giro’s Roc Loc Trail Air retention cradle is one of the comfiest and easiest to use, and features thin, rubber padding on its internal edges to help bolster comfort against the head even further. The indexed dial, which lets you tailor fit, is easy to use one handed too.

The Manifest Spherical’s peak doesn’t have pre-designated positions like some helmets, instead it’s able to stop anywhere within the 15 degrees of movement Giro has given it.

This means there’s still enough room underneath it to stow goggles if you’re not wearing them, but no chance of the peak creeping up so high it starts to look like some kind of head-mounted air braking device.

At the rear of the helmet, Giro has included a textured rubber panel, designed to grip onto goggle straps to better keep them in place.

If goggles aren’t your thing, then there are also some neat glasses-related features too, including two grippers that sit just inside the two, larger front vents. These are designed to grip onto the arms of your glasses if you want to stash them on your helmet while climbing. It’s a tidy little feature and works well on the trail too.

Finally, the FidLock magnetic buckle helps with getting the Manifest on and off a little quicker. It’s bulkier than a standard clip buckle and has sharper edges, though.

Giro Manifest Spherical helmet performance

I’ve been putting the Manifest Spherical through its paces since its launch back in May.

On the trail, there’s no getting away from just how breezy the Manifest feels. Even at slower speeds, you really can notice the air flowing in through the large port above the brow of the helmet and across the top of your head.

Compared to the TLD A2 and Bell 4Forty helmets, which I rode it back to back with, the Manifest is noticeably cooler, even at slower speeds. It feels lighter too, despite the weights being relatively close.

While helmet fit is subjective, I found the Manifest to be incredibly comfortable and secure (just as I did the Montaro and Chronicle), without needing to ratchet the new Roc Loc retention cradle up brain-squeezingly tight to keep it in place.

The tension around the head feels nice and even and I never suffered any hot spots or pressure points, even on long rides on hot days.

Giro’s padding manages to be thick enough to not just keep things comfortable, but also absorb enough sweat to prevent it dripping down into your eyes when you’re really working hard. It’s not overly thick like some can be either, so doesn’t feel excessively plush or hot.

Unlike other helmets I’ve used that feature a FidLock closure, I had no issues with the Manifest’s. In the past, I’ve found that due to the size of the buckle it sat too close to my neck and irritated. Thankfully that didn’t happen here and I’ve not had to readjust it mid-ride to keep it feeling comfy, which is always a plus.

When worn with glasses, it’s important to remember that, just like a road helmet, you’ll need to wrap the glasses’ arms over the helmet straps because the straps sit close to the face.

In use, I had no issues with riding in various glasses (including Smith Attacks and 100% Glendales), and they seemed to cause zero interference with the helmet.

While I can’t say whether or not the new Manifest is safer than the Montaro MIPS or not, it does score a full five stars on the Virginia Tech helmet safety rating.

Manifest Spherical bottom line

Overall, the new Manifest Spherical might be a lot of cash but it’s one of the best vented trail helmets I’ve ever used and packed with numerous neat and very useful features as well as lots of safety tech.

There’s a decent level of coverage and, considering the construction, it’s impressively light too. Plus, unlike early samples of the Giro Tyrant, which also features the Spherical technology, there’s no creaking should the inner and outer liners move ever so slightly over one another while riding.


I regularly ride in a TLD A2 or a Giro Montaro MIPS because they suit my head shape really well and I find them both really comfortable. So I think it speaks volumes that I’ll now regularly grab the Manifest instead, with it being so comfortable to wear on longer rides.

Product Specifications


Price EUR €260.00GBP £250.00USD $260.00
Weight 363g (M) – as tested
Brand Giro


Features Sizes: S (51-55cm), M (55-59cm) , L (59-63cm)
Protection: Spherical Technology
Fit system: Roc Loc® Trail Air Fit System
Vents: 19 Wind Tunnel™ vents with internal channeling
Colours: Matte Black, Matte Black Hypnotic, Matte Blue/Midnight, Matte Grey, Matte Grey Green, Matte Olive, Matte White
Helmet type Mountain bike open face