Giro Merit Spherical review – well balanced helmet with extra protection

Giro’s new Merit helmet integrates spherical MIPS protection into an on-trend downcountry format at a more affordable price

Giro Merit helmet worn by a middle aged man amongst the trees
(Image: © Guy Kesteven)

Bike Perfect Verdict

The new Merit delivers Giro’s unique twin-shell Spherical MIPS protection in a lightweight, well-vented trail/downcountry focused format at a more affordable price


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    Full coverage Spherical MIPS protection

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    Super-secure-yet-comfy feel

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    Well vented at all speeds

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    Easily adjustable

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    Crash replacement scheme


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    Unique tech isn't cheap

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    Not as ultra-breezy as Giro Manifest

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    Complicated light/camera mounting

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    'Decorative' peak

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Giro introduced the Manifest MTB helmet a couple of years ago, giving trail and XC riders the same unique superimposed secondary shell with Spherical MIPS protection that it pioneered on the Aether road helmet. Giro tweaked the format slightly for the open-face Tyrant enduro helmet and now its blended both lids to create the new Merit helmet for riders who push hard on the climbs and the descents. That sounds like hype but when it comes to the best mountain bike helmets, the Merit is as good as Giro claims, and the overall comfort and protective tech are seriously impressive, too. 

Giro Merit helmet

Giro's new Merit helmet is big on ventilation and gets 15 venting ports as a result (Image credit: Guy Kesteven)

Design and aesthetics

Overall, coverage and depth of the Merit are very similar to the Manifest, dropping slightly down at the temples and then the occipital lobes at the rear for a trail/enduro feel, not XC/road exposure. However, rather than perching the outer shell on top of the inner like Manifest, the Merit outer shell is the full coverage section. That means you get the rotating ‘slip plane’ MIPS protection from all angles of impact. Both in-moulded hard shells are much thinner too, with an EPS construction for the outer piece and a slower rebound EPP foam for the inner.  

The straps mount into the hard-shell edge of the outer shell which makes flipping the lid on easy but seems counterintuitive to the operation of the twin-shell design. In reality though, it’s the cradle inside the inner, not the strap that’s holding the helmet onto your head. The snaplock buckle on the colour coded straps isn’t as fancy as a sliding magnetic Fidlock clasp but it still works fine.

For a 56-59cm medium, the Merit is fractionally lighter (361g vs 365g) than the Manifest and far lighter than the 622g Tyrant so your neck won’t suffer on long days out or head-banging descents.

Giro Merit helmet

It's not overly bulky and tips the scales at 361g for a medium (Image credit: Guy Kesteven)


There’s no creaking when it’s moved either, although that probably won’t be your first thought if you’re headbutting the ground hard. While we’ve crashed in Spherical MIPS lids a few times now, it’s impossible to verify the effectiveness of the system apart from saying we felt fine afterwards. Giro has been at the forefront of MTB safety tech for over thirty years though and having visited the company's in-house ‘Dome’ test lab in the hills above Santa Cruz, I can confirm it goes the extra mile with crash test protocols and thermal head-form modeling.

In terms of fit, the RocLoc Trail Air fit cradle is height adjustable with a sliding central ladder rather than press studs which makes tuning pitch a lot easier and security and comfort are excellent. In fact, the slightly thinner Ionic+ padding actually makes it feel more secure and ‘gripped’ than the XT2 padded Manifest. 

Giro Merit helmet

The men's version is available in sizes small, medium, and large, and in the choice of six different colors (Image credit: Guy Kesteven)

The Merit doesn’t get the ‘Aura’ crown arch of the Manifest either so the crown vents are noticeably smaller and that pattern continues over the rest of the lid. There are still plenty of vents all over the shell, which are backed up with internal channeling to suck air over your head and out of the exhaust ports at the rear. That means it’s not as super-breezy as the more expensive helmet, but compared to most trail/enduro options it’s still a conspicuously cool lid on both slow climbs and flat-out descents. 

You even get small brow vents in both inner and outer shells to reduce sunglasses lens steam up. If you want to stow your sunglasses, the arms will slide securely into the vents and there’s a rubber goggle strap retainer strip on the back of the Merit, too. You get an adjustable/replaceable visor as well but, like most helmets, we’ve tested recently, you can’t actually see it in your eye-line so it’s more decorative than functional. 

There’s no GoPro mount peak option either and fitting a strap-on helmet mount for a camera compromises the Spherical MIPS functionality, and it’s a definite no with an Exposure Joystick light mounted on a through-vent mount, so it’s not the best choice of helmet if you’re into video or rides after dark. 

Giro Merit helmet

The Spherical system comprises two layers that are joined with elastomers (Image credit: Guy Kesteven)


Giro’s Manifest has been my go-to XC/gravel helmet since it came out and the outstanding venting means it probably remain that way, but it does come with a not-insignificant price premium over the Merit. 

The complete Spherical MIPS coverage and more secure feel of the Merit gives a more reassuring trail/enduro vibe with no weight penalty. The Merit is still well ahead of most of its competition in terms of airflow and therefore long-ride comfort, and it covers all the essential aspects to play nicely with the best mountain bike sunglasses. While Spherical MIPS complexity doesn’t come cheap Giro runs a cut-price crash replacement scheme to protect your investment (and your head). 

View the Merit helmet at Giro.

Tech specs: Giro Merit helmet

  • Price:  $220 / €199.99 /  £189 / AU$329.99  
  • Sizes:  S, M, L (men) / S, M (women)
  • Rotational protection: MIPS Spherical
  • Colors: Six (men) / three (women)
  • Weight: 361g (medium)
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