You pay a price for ultimate protection with Giro’s Manifest Spherical helmet

Giro’s new high-end trail helmet is packed full of tech but doesn’t come cheap

Giro Manifest Spherical MIPS mountain bike helmet

Giro’s new Manifest Spherical is a feature-packed helmet that’s designed to keep trail riders as safe as possible.

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Giro calls it a “true halo product” and its pricing certainly echoes that (£250/ $260/ €270) and makes it one of the most expensive, if not the most expensive, trail helmets on the market.

Giro wanted to make one of the safest trail helmets you can buy when designing the Manifest Spherical, but it didn’t stop at safety.

It’s put a lot of time and effort into making the Manifest Spherical one of the best-ventilated helmets too, and claims that its performance rivals that of a road helmet.

There are also a lot of other well-considered touches, which is nice to see when you consider how much this new lid will set you back.

Giro Manifest Spherical helmet construction

Giro Manifest Spherical MIPS mountain bike helmet
The Spherical MIPS means the helmet has two shells.

At the core of this new helmet is Giro’s Spherical Technology, which was designed in conjunction with MIPS (Multi-directional Impact Protection System) – as seen in its Aether road helmet and, more recently, its Tyrant trail helmet. 

Giro was quick to point out a minor tweak to the naming of the safety technology used in the Manifest.

While it’s known as ‘MIPS Spherical’ in both the Aether and Tyrant helmets, Giro has changed it to ‘Spherical Technology powered by MIPS’ because the design was developed by the helmet brand in partnership with MIPS, but not designed by MIPS itself.

What is MIPS Spherical Technology?

Giro Manifest Spherical MIPS mountain bike helmet
The two shells act like a ball and socket, with the internal one able to rotate inside the outer.

Giro describes it as a ball and socket construction, consisting of an outer and inner liner. The design allows the outer liner to rotate around the inner liner during a crash to stop your head contacting a slip-plane (just as you’d get with the standard MIPS design).

This then helps to redirect forces away from the brain during a crash and is said to make a real difference during angular impacts – the type of crash you’re more likely to experience when falling off of a bike.

Different density EPS foam liners

Giro Manifest Spherical MIPS mountain bike helmet
Giro Manifest Spherical MIPS matt black helmet.

The two liners are made from separate layers of EPS foam, each with a different density and designed to better deal with different types of impact.

Giro says that the inner liner (the one that sits against your head) is constructed from a “less dense foam”, which it claims is more comfortable and better suited to low-speed impacts.

The in-moulded outer liner (which is covered by the helmet’s outer shell) uses a denser EPS foam, which is better at protecting the head against high-speed impacts.

Large vents for efficient cooling

Giro Manifest Spherical MIPS mountain bike helmet
We think the lid looks good.

It’s the large vents that run across the top of the head combined with the internal channelling that are said to help make the Manifest rank among the coolest out there. But surely using vents of this size impacts on safety?

Giro’s Aura Reinforcing Arch

Understandably, yes, it does, but this is where Giro’s ‘Aura Reinforcing Arch’ comes in.

In between the two longest, central vents that run across the top of the helmet, there’s a semi-transparent material that bridges each vent.

This impact-resistant polycarbonate band spans the outer shell of the Manifest and is said to bolster the helmet’s strength and structural integrity without getting in the way of airflow.

Thanks in part to these massive vents, Giro claims the Manifest Spherical isn’t just really safe, but is also 7 per cent cooler than its current top-tier trail lid, the Montaro MIPS, and ranks just behind its top road helmet, the Aether MIPS, which also features MIPS Spherical Technology.

Overall weight for our medium test sample is 363g, which is lighter than the Giro Montaro MIPS and Troy Lee Designs A1 MIPS helmets.

Giro Manifest Spherical helmet fit system

Giro Manifest Spherical MIPS mountain bike helmet
Giro’s Roc Loc fit adjuster makes it easy to tune the lid’s fit.

While a helmet can be built to withstand just about anything, if it doesn’t stay on your head when it matters most, then, ultimately, it’s pretty useless.

The Manifest Spherical is held in place using Giro’s Roc Loc Trail Air retention system. The Roc Loc system isn’t exactly new technology (Giro introduced it back in 1994 – anyone remember the rather cool Supermoto lid?), but it’s been refined over the years.

The current offering is rather slick in operation thanks to the chunky, indexed adjuster wheel (the same is used on the Tyrant helmet), which makes tweaking the fit nice and easy.

Giro Manifest Spherical MIPS mountain bike helmet
The peak’s adjustable so goggles can be stored on the front of the lid.

The cradle encircles the entire circumference of the head which helps to provide a more even tension when you’re cranking up the tightness.

There are also three different height adjustments for the cradle to ensure you get it sitting just right on your head.

To boost comfort, Giro has included a rubber back and some thin rubber padding on the inside of the cradle at the rear.

In a bid to increase ventilation that bit further, Giro says that the new Roc Loc fit system is designed to provide a 3mm gap between the brow of the helmet and the forehead. This apparently helps to encourage air to flow up and into the helmet.

Increasing comfort, decreasing microbes

Giro Manifest Spherical MIPS mountain bike helmet
The liner is anti-microbial.

Aside from fit, getting the padding just right isn’t easy either. Use padding that’s too thin and it won’t be very comfortable or absorb much in the way of sweat when you’re working hard, while padding that’s too thick might be comfy but can feel really hot.

Giro has landed somewhere in the middle with the XT2 anti-microbial padding used in the Manifest, all of which Velcros into place to make it easy to remove when it does start to stink.

Finally, when it comes to fit, we need to talk about the straps.

These are anchored to the inner shell and sit just inboard and close to the head. Giro did this in a bid to create a helmet that’s compatible with a wider range of glasses (the arms will generally always sit over rather than under the straps).

Giro Manifest Spherical MIPS mountain bike helmet
The Fidlock buckle should make undoing and fastening the strap easy.

The closure is taken care of courtesy of the magnetic FidLock buckle. While there’s no doubt these magnetic clasps are a doddle to use, they are bigger than the more traditional helmet buckle they replace and not all riders get on with them.

Giro Manifest Spherical helmet details

It seems Giro has done its very best to try and cover trail riders’ needs when it comes to additional features with the Manifest.

Take a look at the rear of the lid and you’ll spot a textured, rubberised gripper strip about halfway up the helmet. This is designed to cling onto goggle straps and help keep them securely in place.

Giro Manifest Spherical MIPS mountain bike helmet
Goggle straps are less likely to slip down with the Goggle Gripper.

Like many of Giro’s other trail helmets, the Manifest’s peak is adjustable and can be shifted up far enough to stow goggles underneath it.

The peak won’t shift up as high as on the likes of the Montaro or Tyrant though, which can end up pointing skyward and acting like an air brake.

Instead, the Manifest’s visor has 15 degrees of adjustment but doesn’t have incremental detents, like those found on some other models from Giro. This means you can move the peak anywhere within that 15 degrees of adjustment rather than pre-defined locations.

It should also help to avoid you leaving your peak wonky after adjusting it.

Giro Manifest Spherical MIPS mountain bike helmet
The glasses grippers should help reduce the chance of stowed-specs falling off the lid.

Another nice little touch is the small, textured glasses grippers, which sit inside the inner liner, just under the front right and left vents.

These are designed to help hold onto your glasses’ arms when you stow your specs on top of your lid and should be really handy on humid days when your glasses are constantly fogging on slow, sweaty climbs.

Giro Manifest Spherical MIPS mountain bike helmet
There are reflective panels on the rear of the lid.

Reflective detailing at the rear of the Manifest should help to improve visibility if and when you do ride on the road at night.

There are seven colours to choose from – matt black, matt black hypnotic, matt blue/midnight, matt olive, matt grey, matt sage and matt white – so colour matching to your favourite kit shouldn’t be a problem.

Giro Manifest Spherical helmet specifications and price

  • Spherical Technology powered by MIPS
  • Progressive Layering
  • Wide-open ventilation
  • AURA reinforcing arch
  • Roc Loc​ ​Trail Air fit system
  • Fidlock magnetic buckle
  • Adjustable moto-style screw-in visor
  • Quick-dry XT2 anti-microbial padding
  • Goggle gripper
  • Integrated eyewear grippers
  • Lightweight webbing
  • Reflective decals on rear of the helmet
  • Small (51–55cm), medium (55–59cm), large (59–63cm) sizes
  • Matt black, matt black hypnotic, matt blue/midnight, matt olive, matt grey, matt sage, matt white colours options
  • £250 / $260 / €270

Giro Manifest Spherical helmet first ride impressions

Giro Manifest Spherical MIPS mountain bike helmet
Giro’s new Manifest Spherical helmet uses its Spherical Technology, which was designed in partnership with MIPS.
Robin Weaver

Due to the current lockdown restrictions, I was unable to test the new Manifest Spherical helmet properly, but I have been wearing it during my gentle daily exercise rides, which has helped me to get a rough idea of how it feels out in the wild.

As you’d hope from such a pricey helmet, the quality of the Manifest seems top-notch, with a solid, well-built feel as soon as you slip it onto your head.

Giro Manifest Spherical MIPS mountain bike helmet
Being able to securely stow glasses on top of the helmet is handy when tackling slow, sweaty climbs.
Robin Weaver

Obviously helmet fit is a very subjective thing, but Giro’s helmets always tend to work well on my head and this model is no exception. Adding tension through the Roc Loc adjuster wheel is quick and easy, providing an even compression around the head with no hot spots or pressure points.

The FidLock closure is quick and easy to use, but I did find it irritating my neck from time to time. A slight readjustment of the straps helps alleviate this, but I’ve found that it doesn’t cure the problem totally.

Giro Manifest Spherical MIPS mountain bike helmet
There’s a generous amount of padding to ensure the Manifest remains comfy but is also able to absorb sweat when you’re working hard.
Robin Weaver

The most noticeable thing is just how breezy the Manifest feels across the top of my head, definitely more so than when wearing my Troy Lee Designs A2 helmet and not that far off my Giro Aether road helmet. Impressive stuff. As for how it feels on the trail, I’m currently unable to say, unfortunately.

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I’ll be doing a full review of the Manifest as soon as restrictions are lifted and we can safely ride and test again, so please stay tuned for that.

Giro Manifest Spherical MIPS mountain bike helmet
A dropper rear helps bolster coverage, while the goggle gripper, neat rubber graphics and reflective detailing all help add to the overall appeal.
Robin Weaver