Giro Synthe II (MIPS) Helmet Review: Tried and Tested

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Review score


Giro Synthe II is an excellent, premium all-around road cycling helmet. It is super comfortable to wear, lightweight, looks stylish, and offers excellent ventilation. In addition, it is well priced and includes good safety features (MIPS). I only deducted 1 point due to slight issues with my cycling glasses’ compatibility.

product and testing details:

The primary function of any helmet is to keep cyclists safer in the event of a crash. However, in addition to safety, I personally want my cycling helmet to look great, be light, offer plenty of ventilation, and just be comfortable to wear. This is why I chose the Giro Synthe II helmet (MIPS), as it looked like a perfect candidate for my needs and budget during the research stage. After using this helmet for a few months, I am ready to share my thoughts.

I hope you find my detailed review of the Giro Synthe II helpful in deciding whether this is a helmet for you. Leave comments below if you like the review or have any questions or feedback.


Fit is always very personal when it comes to cycling helmets. It’s because we all have different head shapes. So a helmet that fits one person perfectly might not suit another.


Having said that, my head shape is diamond, and the Giro Synthe II helmet fits me very well. I feel slight discomfort on both sides of my head when putting the helmet on, but it disappears as soon as I tighten the adjustment system and the pressure distributes evenly around my head.


This is why scoring this helmet a strong 10/10 for the fit.


The Giro Synthe II helmet is very light. In fact, it’s one of the most lightweight helmets on the market at this price range. Its weight differs in the U.S. and the EU due to different safety regulations (as a result, construction is different). For example, size Medium weighs 275 g / 9.7 oz in the U.S. and 265 g / 9.34 oz in the EU.


In my case, size S weighs 260 g / 9.17 oz in the U.S. and 250 g / 8.81 oz in the EU. This helmet is 50 g / 1.76oz lighter than my previous one, which is a substantial upgrade.


You obviously don’t want to ride around with extra weight and pressure on your head and neck. However, with the Giro Synthe II helmet, you do not have to worry about this.


Overall, I’m happy with the Giro Synthe II helmet’s weight and give it a score of 10/10.


If you are very stressed about a helmet’s weight, it is possible to find an even lighter one. For example, Kask Mojito 3 weighs about 230 g / 8.11 oz (Size M), but I am personally happy with the Giro Synthe II as it looks better (my subjective opinion).


The Giro Synthe II helmet comes with the Roc Loc® 5 dial (the newest and most advanced version of the Roc Loc® system). It allows you to easily custom tune the fit tension and the fore-aft tilt of the helmet in seconds using a single hand.


As I mentioned above, I feel a slight discomfort in fit when putting the helmet on, but it disappears as soon as I tighten the adjustment system. The dial is straightforward to use, and the 360-degree adjustment creates a very comfortable fit (snug and hugging).

The helmet straps are adjustable and can be moved up or down to ensure they sit perfectly around your ears. This often is not the case with other helmets, so I am happy with the Giro Synthe II in this respect.

Well done, Giro, and that is why I am giving Synthe II helmet a 10/10 score for the adjustability. However, the Roc Loc® 5 dial does get in the way of my sunglasses (more about this below).


The Giro Synthe II helmet comes with 19 vents and is equipped with an internal air channeling system to pump cool air in and warm one out.

In my opinion, it does an excellent job. I never felt my head getting too hot, even on the longest and most difficult rides.

Overall, I found ventilation on Giro Synthe II excellent and scored this helmet a 10/10 for ventilation.


Multiple factors determine the comfort of a cycling helmet. For example, how well it sits on your head, how heavy it is, how ventilated, and how comfortable the padding and adjustment system is.

I found no issues with Giro Synthe II when it comes to comfort. The helmet is very light, highly adjustable, and very well ventilated. I stop feeling it on my head after a few minutes on the bike, which speaks a lot about this helmet’s comfort level.

This is why I scored it a 10/10 for comfort – another perfect mark!

Design and Aesthetics

The Giro Synthe II helmet looks very sleek, stylish, and subtle (the matte finish looks great!). I also really like its shape and how compact it is.
This helmet is available in multiple colors, and you can definitely find one that will match your bike or kit.

I think design and aesthetics are pretty important when it comes to cycling helmets. It’s the first thing people see, and it is easy to get a helmet that makes you look like a dork.

Giro has definitely got their design and style right with the Synthe II helmet, and I gave it a score of 10/10.


Luckily, I did not need this helmet to save me in a crash, so I can’t speak about its safety level from a firsthand experience. However, this is what I have observed about its safety:

First, the Giro Synthe II helmet has an integrated MIPS (Multi-Directional Impact Protection System). This safety system is supposed to reduce the rotational forces on the brain in certain types of crashes. Unfortunately, there is hardly any independent research on the effectiveness of MIPS, but I personally feel more comfortable with it rather than without it. Also, most helmet manufacturers have opted for MIPS or a similar system, so I assume it should add value to the end-user.

Second, Giro Synthe II comes with a molded-in roll cage reinforcement. It adds strength and durability to the helmet in case of an impact.
Third, the helmet does feel strong and durable when you hold or wear it.

I will not score this helmet based on its safety features as I don’t have a way of testing it properly. However, I hope that my subjective safety observations above are helpful. Also, each helmet must comply with helmet safety requirements of the country where it is sold.

Cycling glasses compatibility

The Giro Synthe II helmet is not 100% compatible with my sunglasses (Oakley’s Radar EV Path). This is because the Roc Loc® 5 system interacts with the temple tips of my cycling glasses and slightly pushes the glasses up. Fortunately, this is not a big problem, and the glasses still fit me well while wearing this helmet. However, it is a slight issue, but ideally, I don’t want to experience it.


Keep in mind that this might not be an issue for you and your sunglasses as there are so many different models out there. Since it is a slight problem for me and probably not a universal matter, I will deduct just 1 point and score the Giro Synthe II helmet 9/10 for “cycling glasses compatibility”.


By the way, here is my in-depth revenue of the Oakley Radar EV Path Cycling Glasses.


Giro Synthe II helmet retails for around $200, which is in line with other premium helmets on the market. In my opinion, this helmet is definitely worth the money as it ticks all the boxes for me: excellent ventilation, comfort, safety features, looks good, light, and offers a great fit. Also, based on my research, I can say that this helmet provides more value than some more expensive choices.


In summary, these are the things I like about the Giro Synthe II road cycling helmet:


The Giro Synthe II helmet is very light. In fact, it is the most lightweight road bike helmet that I have ever owned and worn.


The Roc Loc® system works great and allows you to easily and quickly adjust the helmet’s fit.

Design and Aesthetics

In my subjective opinion, this helmet looks great. It is also available in multiple colors and has a sleek and slightly aerodynamic design (less drag).

Safety features

The helmet comes with an integrated MIPS system and seems to be very well constructed.


This helmet offers great ventilation. I never felt like my head was getting too hot while wearing it.


This helmet is extremely comfortable. I forget that I am even wearing it after a few minutes on the bike, which speaks a lot about the comfort.


What I did not like about the Giro Synthe II road cycling helmet:

Cycling glasses compatibility

The helmet is not 100% compatible with my cycling glasses. This is a minor issue but something to keep in mind if you use similar cycling glasses.

Final Verdict

The Giro Synthe II helmet is an excellent choice for road and gravel cyclists looking for a comfortable, light, stylish and well-ventilated helmet. It is also very well priced for the quality you get. Overall, it ticks all the boxes for me, and I can highly recommend it.
I was only slightly let down by the helmet’s compatibility with my cycling glasses.

Alternative Road Cycling Helmet Recommendations

If you are not set on the Giro Synthe II helmet or just want to check out alternatives, we have put together two articles with the best road bike helmet recommendations:


Best Road Bike Helmets Under $100

Best Road Bike Helmets Under $200

Choosing a perfect road bike helmet depends on your needs and goals. For example, if you want the lightest helmet for long-distance cycling, then Kask Mojito 3 Road Bike Helmet is a great choice. However, if look and style are your top considerations, then POC Omne Air Spin or Bontrager Velocis MIPS are great alternatives.

Frequently asked questions:
1. Is the Giro Synthe MIPS?

Yes, the Giro Synthe II helmet comes with an integrated MIPS system.

2. How much does the Giro Synthe II helmet weigh?

Its weight differs in the U.S. and the EU due to different safety regulations. For example, size Medium weights 275g / 9.7 oz in the U.S. and 265g / 9.34 oz in the EU. 

3. Does the Giro Synthe come in different colors?

Yes, it does! The Giro Synthe II helmet is available in 8 colors, so there are plenty of options to choose from.

4. Is Giro a good helmet brand?

Giro is a well-respected helmet brand with a long history of making high-quality products. Professional cyclists and amateurs alike use their helmets. Our favorite Giro helmets include the Giro Synthe MIPS, Giro Cinder MIPS, and Giro Aglis MIPS.

5. How long do Giro helmets last?

According to Giro, helmets have a lifespan of about 3 to 5 years. The lifespan of a helmet depends on exposure to the elements (e.g., sun, rain, etc.) and overall care.

6. What is the best Giro helmet?

The best Giro helmet depends on your specific needs and preferences. However, some popular choices include the Giro Synthe II, Giro Aether, and Giro Syntax.

7. Which alternative helmets would you recommend?

Some popular alternative helmet brands include Bontrager, Specialized, and POC.


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