Giro Merit Spherical Review – Ridden and Reviewed

In this Giro Merit Spherical review, we look into how the Giro Merit stacks up against the Giro range, and other helmets of similar price. 

The latest mountain bike helmet from Giro is a top of the line trail helmet, made for those wanting a heap of safety features while still maintaining a phenomenally light weight. 

We’ve tested the Giro Merit Spherical Helmet on some of New Zealand’s best trails. Long steep climbs and techy descents make up the best of Nelson’s trails, making it the ideal place to test out the Giro Merit.

So what makes the Merit so special? The helmet utilizes MIPS Spherical technology, which has been reserved for only the highest of the top-end helmets from Giro and Bell to date. Introducing this feature to a helmet with a lesser price tag opens up an opportunity for those wanting to utilize a fantastic safety feature without a hefty price. 

We have found that the Giro Merit is the ideal helmet for taking on any trail ride. It is light, comfortable and has the safety spec that help make you feel comfortable on the tracks.

Giro Merit Spherical Helmet

Highly recommended for beginners through to advanced trail and enduro riders. With MIPS Spherical, progressive layering and great coverage this is a top end helmet not to be overlooked!

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  • MIPS Spherical
  • Lightweight
  • Very well ventilated
  • Exceptional sweat absorption
  • Excellent protection
  • Comfortable (plush Ionic padding)
  • A few good colorways


  • Visor has a limited range of movement
  • No integrated light/camera mount
  • Looks a bit like a road helmet


The Giro Merit Spherical helmet is certainly not lacking in any safety features. Spherical is an advanced version of MIPS (Multidirectional Impact Protection System – see more here). 

For those that aren’t aware of the MIPS Spherical technology, a basic explanation is that there are two shells where a normal helmet would have one. One shell is made of a harder material which absorbs high energy impacts. And the other is softer, absorbing slower, lower energy impacts.

The combination of the two layers mean less direct (linear) energy is directed to the skull.

MIPS Spherical
The outer layer is the turquoise with the ‘spherical’ written on it, and it moves independently to the black and white layer inside it in a crash.

The main feature of having the two shells is that they move relative to one another, with a slip plane or rubber bands connecting the two. This allows the outer shell to move and absorb more energy from a rotational impact than the inner layer. This is very similar to the usual MIPS, which has a plastic liner, rather than two separate shells. 

The Merit has reasonable coverage of the rear of the head and temples. This is pretty important (and pretty standard these days) to keep as much of the head covered as possible for awkward knocks and tumbles.


Giro are not ones to skimp on research and testing, and that much is evident when it comes to the breathability and ventilation of the Merit. The helmet has been through wind tunnelling to create the optimum airflow. 

The other main advantage of the spherical technology, is that air can flow between the two shells. This allows air to pass over the head, constantly cooling you down. 

I notice this even at lower speeds- while climbing especially. 

Rear of the Giro Merit
Heaps of vents at the back, top and sides of the helmet.

Comfort and Sizing

At 360 g (size medium) the Merit isn’t heavy. In fact, when each of us picked it up, the immediate reaction was ‘s**t that’s light’.

It is a pretty similar weight to the Specialized Ambush II (approx 360g), but lighter than the likes of the Fox Speedframe Pro and the POC Kortal Race MIPS (both a little over 400 g).

Giro’s Roc Loc Trail Air retention system has a large dial at the rear of the head, which is easy enough to change while riding- even with gloves on. The dial increases and decreases the tightness of the helmet in finite increments, allowing you to obtain the perfect fit.

Roc Loc Trail Air
Large dial for ease of adjustment

Giro has refined the system so that you won’t get any pressure points around your head. Combined with the Ionic+ padding, the soft cushioning around the head will make you never want to take it off!


The ‘screw-in visor’ allows the visor to be adjusted to keep the sun and rain out of the eyes. However, the range of adjustability is pretty limited. The visor doesn’t really sit high enough to store goggles (although glasses would be fine).

If you don’t worry about riding with goggles, then the range is plenty to get the visor out of your line of vision at its highest, and keep the elements out of your eyes at its lowest.

The screw-in setup allows the visor to sit at any position you like- no set increments like the Giro Source and many other lids.

Summary of Features

  • MIPS Spherical
  • Progressive layering- dual density inner and outer layers of foam
  • 15 Vents- with internal air channeling!
  • Adjustable visor
  • Goggle gripper
  • Antimicrobial padding (this isn’t to be underestimated. If you happen to take your helmet off while very sweaty, it dries faster and doesn’t smell. Making it much more pleasant to put it back on again!)
  • Roc Loc Trail Air fit system – which essentially ensures a comfortable

Features it’s missing:

  • No integrated light/camera mount. A bit disappointing for those who enjoy a bit of night riding or filming, and like the ease and safety of an integrated light/camera.
  • No sweat guide system. Unlike many of Giro’s helmets, the Merit doesn’t feature a system that directs the sweat away from the eyes.
  • No Fidlock buckle. A handy feature, but certainly not essential.

Comparison and Value

The Giro Merit fills a gap in the Giro helmets range between the Giro Manifest Spherical (the top range, high performance lid) and the Giro Source (all you need and nothing extra kind of helmet). 

The Manifest is the more expensive, slightly heavier helmet, with upgrades such as Fidlock (magnetic) buckle and an Aura Arch (strengthens the helmet) rather than a more traditional style helmet. The Merit is lighter, cheaper and likely all (and more) that you need in a good half shell helmet.

When compared to the Giro Source (one of my favorite helmets from last year- and I still consider this very good value for money) it is a league above. It is much lighter, more ventilation, and has significantly more safety features. But, the Giro Source is slightly cheaper (see the full review here).

The Merit is reasonably similar in price to the Troy Lee Designs A3 (see the full review here). The A3 has slightly better coverage – it sits a bit lower on the head – and the A3 has a bit plusher padding.

Final Thoughts

I really like the Giro Merit. It stands out to me as a phenomenally lightweight, yet packed with safety features and rider usability features.

I have recommended this helmet to my Dad who enjoys smashing out the trails, but wants something that’s pretty breathable and he won’t notice it while he is wearing it. The visor gives him somewhere to store the goggles, and the large dial at the back of the helmet makes adjusting the fit easy.

Giro Merit MTB helmet review

For more posts like this, check out our review of the Met Parachute MCR (its a convertible helmet!), the best helmet for large heads, and what makes a good MTB helmet.