Giro Manifest Spherical MIPS trail helmet review

Does Giro’s unique new Manifest ‘double-decker’ trail helmet really vent as well as a road race lid while still providing state of the art ‘slip-plane’ brain protection?

Giro Manifest helmet review
(Image: © Guy Kesteven)

Bike Perfect Verdict

Unique double-decker MIPS protection with excellent ventilation and practical features make Manifest an awesome trail helmet for those who can afford it


  • +

    Next level protection at most angles

  • +

    Exceptional ventilation for a MIPS lid

  • +

    Super comfortable fit

  • +

    Excellent optic security details

  • +

    Barely bulkier than a normal lid

  • +

    Decent weight


  • -

    Very high price

  • -

    No ‘spherical effect’ on side impacts

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Giro introduced its ball-and-socket helmet design on the Aether road helmet a couple of years ago, then followed it up with the brilliant-but-bulky Tyrant. Manifesto refines and reduces the concept to boost ventilation and reduce bulk and weight while still delivering next-level protection at most impact angles. It’s certainly not a budget head bucket though.   

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MIPS protection is based on deliberately letting the helmet rotate around your head during impact to reduce peak G-force loading on your brain. This is normally achieved with a cradle tethered to the shell on stretchy shock-absorbing elastomers. MIPS Spherical goes a stage further and uses elastomer tethered inner and outer helmets sliding over each other to reduce the Gs. The lower helmet is also made of a different density designed to absorb low-speed loads while the upper segment is designed to dissipate high-speed loading better. Unlike the Aether and Tyrant the upper section doesn’t wrap all the way around the inner so the sides and lower half of the helmet work as normal with no MIPS spherical protection.

Manifest isn’t just about Spherical MIPS though. It uses a new, padded, dial adjusted Roc Loc Trail Air cradle with wider spaced rear verticals for better airflow and a magnetic FidLock catch on the straps. The upper helmet is reinforced with a translucent ‘AURA’ arch which allows Giro to use 19 Wide Open vents with further channelling inside. With no MIPS cradle to add bulk, Giro has fitted relatively fat, microbial silver enhanced pads, too. The peak is bolted and angle adjustable and there are rubber gripper patches on the back of the helmet for goggle stars and inside the crown for glasses. There are subtle reflective details on the rear and it comes in seven colours, with the slip plane ‘sandwich’ filling picked out in a contrast colour so people know you’ve invested big in protecting your brain. 

Giro Manifest helmet review

The outer shell covers the top section of the helmet (Image credit: Guy Kesteven)


Fit is crucial with a helmet and the new Trail Air cradle takes an already very inclusive fit and together with fatter pads than we’ve become used to on MIPS helmets makes it feel fantastic. It’s super-secure even with the straps undone and while the buckle is bulky it’s ‘self-seeking’ closure mechanism is awesome. The bolted visor moves through a really wide range of angles but stays secure on rough descents and the little rubber goggle strap and glasses arms grabbers work brilliantly to secure your optics.

The stacked-rather-than-wrapped design also keeps the width of the helmet down so it doesn’t look like a massive bucket on your head and at 365g it’s not a strain on your neck either.

Giro wasn’t bluffing about the ventilation either, with impressive airflow - particularly over the crown - at all riding speeds. That stands it well above most conventional MIPS helmets we’ve used in terms of cooling.

The fatter pads can hold more sweat if you’re working hard in it for a long time but the silver anti-bac effect should hopefully keep them smelling okay for longer between washes.

What we can’t comment on is the actual effectiveness of the MIPS Spherical Technology in terms of safety gains. All we can say is that when we visited Giro’s HQ and design centre in California the company clearly spends a huge amount of time and money taking its testing way beyond the basic ‘good enough to be legal’ standards and often in more practical, real-world ways.


Giro’s Manifest is a super-smart, super-comfortable, cool-riding trail lid that’s loaded with a whole menu of small but worthwhile details. It also delivers what’s claimed to be next-level brain protection while still keeping weight reasonable and ventilation excellent. That makes it hard to fault for regular trail use apart from the fact all these features mean a stinging price tag. ‘Conventional’ side protection means we’d also recommend the heavier, bulkier but full Spherical coverage Tyrant if you’re a regular headbanger.  

Tech spec: Giro Manifest helmet  

  • Sizes: S, M, L
  • Vents: 19
  • Buckle: Fidlock magnetic
  • Colours: 7
  • Weight: 365g (medium)
  • Price: £249.99
Guy Kesteven

Guy has been working on Bike Perfect since launch in 2019. He started writing and testing for bike mags in 1996. Since then he’s written several million words about several thousand test bikes and a ridiculous amount of riding gear. To make sure he rarely sleeps and to fund his custom tandem habit, he’s also penned a handful of bike-related books and talks to a GoPro for YouTube, too.

Current rides: Cervelo ZFS-5, Specialized Chisel, custom Nicolai enduro tandem, Landescape/Swallow custom gravel tandem

Height: 180cm

Weight: 69kg