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Item # GIR007D

No compromises.

In setting out to design the all-new Synthe Helmet, Giro's stated aim was to eliminate the false choice between aerodynamics and ventilation. It apparently worked. According to the world-class Marianne Vos, the Synthe is "perfect for every race. You don't have to choose between the two anymore, you can just wear this one." Giro also chimes in, claiming that the final product is the "fastest aerodynamic profile of any road helmet we've ever made." That's saying something, coming from the same company that brought us the revolutionary Air Attack helmet.

OK, that was a lot of talk but not much evidence of walk. But rest assured that Giro did walk. It walked all the way to the wind tunnel, where it used a metric called Wind Average Drag not to verify that what they had already made was aerodynamically sound, but to actually design the Synthe from the chin strap up. Wind Average Drag produces a single drag value from 72 possible wind angles. By not giving any plain or vent a free pass, Giro has produced a helmet that it claims reduces drag more than most of the non-ventilated, pure-aero road helmets that have flooded the market.

Despite this impressive wind tunnel performance, Giro still proudly asserts that the Synthe excels most in the comfort category. The Synthe's defining element is the incorporation of Aero Mesh Panels, an idea that we typically associate with summer-weight bib shorts. By contributing positively to both, the Aero Mesh Panels are the bridge between aerodynamics and ventilation. In a stroke of functional genius, the panels also include vents that double as ports for glasses.

The Roc Loc Air fit adjuster is operable with one hand, to (literally) dial-in pressure and fore/aft tilt for the perfect ride — even while you're in the middle of it. Air Fit also means that the Roc Loc frame suspends the helmet just enough to facilitate more airflow across your head, which is further boosted by the internal airflow channels and surprisingly-generous-for-an-aero-helmet vents. The Synthe is also a feathery 250 grams (size medium).

The Giro Synthe Helmet is available in three sizes ranging from Small to Large in the colors Blue/matte black, Highlight Yellow/matte black, LE Matte Black/glowing red/blue, Matte Titanium, Matte White/silver, Red/matte black, White/red/blue, and plain ol' Matte Black.

  • Roc Loc Air retention adjustment
  • Ventilation channels to provide cooling to the whole head
  • Optics perch
  • CPSC certified

Tech Specs

Shell Material:
[shell] polycarbonate
Impact Foam:
[liner] EPS
Ventilation:
Aero Mesh Panels, Roc Loc Air
Fit Adjustment:
Roc Loc Air
Visor:
no
Certifications:
CPSC
Claimed Weight:
[medium] 250 g
Recommended Use:
cycling
Manufacturer Warranty:
1 year

Size chart

Giro

Adult Cycling Helmets
 SS/MMM/LLXLAdult UniversalWomen's Universal
Head Circumference 20 - 21.75in
(51 - 55cm)
20 - 22.5in
(51 - 57cm)
21.75 - 23.25in
(55 - 59cm)
21.75 - 24in
(55 - 61cm)
23.25 - 24.75in
(59 - 63cm)
24 - 25.55in
(61 - 65cm)
21.25 - 24in
(54 - 61cm)
19.75 - 22.5in
(50 - 57cm)
Cipher
 XSSML
Head Circumference 20 - 20.75in
(51 - 53cm)
21.25 - 22in
(54 - 56cm)
22.5 - 23.25in
(57 - 59cm)
23.5 - 24.25in
(60 - 62cm)
How to Measure:
For best results, use a tape measure to measure around your head where your hat would fit comfortably.

Reviews & Community

REVIEWS

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Aero is the new light weight

  • Familiarity: I've used it several times
  • Fit: True to size

The Synthe is a pretty cool helmet. As far as helmet options go, it usually seems that for more aerodynamics, both weight and ventilation have to take a back seat. I feel like the Synthe really splits the difference nicely. The helmet has a slightly rounder fit to it, so if you prefer more oval shaped helmets, the fit may not be perfect, but this will fit most people superbly. I absolutely love the sunglass slots too. A very nice touch.

Forget it's there

  • Familiarity: I've used it several times
  • Fit: True to size

I tried a few other brands after my previous helmet needed to be retired. Some of them had nice features, but the Synthe is the best when it comes to being lightweight and aero. A great helmet is one that you don't notice on your head and this is it! Bonus points - super easy to tuck the shades in the holes while riding.

Avg. ride time: 4h 44m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Impact resistant

  • Familiarity: I've put it through the wringer
  • Fit: True to size

Hit an unseen curb trying to get out of the rain. Front ejection and landed on my forehead. Not a scratch on me, not a scratch on the helmet. Great safety helmet. Comfortable.

The perfect helmet!

  • Fit: True to size

Light weight, aero, comfy, and ventilates well. My only gripe is on the roc-loc system is the tiny little plastic tabs/pins near the adjustment dial seem like they could break or wear out

The new benchmark from Giro

  • Familiarity: I've put it through the wringer

In the last year or so, new aero helmets such as the Giro Synthe ($250) and the Kask Protone ($300) have ushered in a new era in road helmet design. These helmets are more rounded-off at the tail, and more aero overall than previous top of the line, all-around, road helmets such as Giro's own Aeon and Specialized's Prevail.

In addition, unlike older aero helmets, newer aero helmets such as the Synthe also ventilate well. Well done Giro!

As for aerodynamics/quietness, if you compare the Synthe to previous top, all-around road helmets (Prevail, Aeon and before that, the Giro Ionos), helmets I rode in for years, there is no comparison. The Synthe is much quieter, especially when you put your head down during hammertime. The shaping at the tail of the old school helmets (Prevail/Aeon/Atmos/Ionos) is now obsolete.

The new Giro Synthe and Kask Protone helmets are "game changers."

Lastly, the ventilation of the Giro Synthe is different (and very effective). You actually feel the cool air running over your head -inside- the helmet (through the internal channels). This is brilliant. Does it vent *quite* as well as the Aeon or the Atmos? No. So, in >85/90° weather, I use my old white Summer helmet (Aeon). But in all other conditions, I much prefer the Synthe.

Versus the Kask Protone, I like the looks of the Synthe more (totally personal). And the Synthe is less expensive.

By the way... Greg van Avermat and Anna van Breggen won the men's and women's 2016 Olympic road race in Rio. And they were both wearing the Giro Synthe road helmet.

Avg. ride time: 3h 39m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Fantastic Helmet from Giro

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: Medium

I came across the Giro Synthe helmet after several friends started raving about how fantastic of a helmet it is.

I was first reluctant to buy a Giro helmet again since I have worn several helmets from Giro (Aeon, Air Attack, Atmos) and have never been a huge fan of their fit systems compared to other products such as Kask and Lazer. The Roc Loc Air system that was put into the Synthe is fantastic and allows me to easily adjust the helmet for when its cold and I need a thermal cap.

The helmet is super light and ventilates very well in the summer. This is a huge benefit compared to other aero helmets such as the Air Attack and Specialized Evade. I cannot say I have noticed any significant aero benefits from this helmet, however its a nice piece of mind to know that this helmet has been tested to show its decently aerodynamic in comparison to other products.

Since I bike in the Northeast in winter, I have taken some brutal falls on ice while wearing this helmet. One significant example is that I fell straight onto my head after my front wheel broke into some thin ice on the bike path. I expected to have a concussion after such a fall, but luckily I was wearing a good helmet and didn't sustain any damage. The helmet was scuffed up, but did not dent at all. Even so I need to replace it since it has been crashed.

The only other product I recommend everyone research is the newer Giro Synthe MIPS helmet. I personally have never worn a MIPS system helmet, but I will be investigating this option for my upcoming helmet purchase.

Great product, would buy it again!

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: Large

Not as aero as the attack helmet, but great liner on the inside of the helmet.

Adequate, safe, comfortable, minimalist

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: Large

All helmets sold in the U.S. meet the same basic safety requirements, so after that it is style, flexibility, weight, and (if you believe in it) wind slipping. The helmet is adequate at all of that, except maybe flexibility. It comes with very little adjustability, but if it fits you won't care. And it fits me, much better than previous Giro helmets.

I use this as a spare helmet, but I do use it on long rides. I just came in from a 5 hour winter ride and it was fine. Not as nice as my Kask or Catlike, but it is fine.

If you want a fine helmet, go for it! If you want something special, there is a lot from which you can choose. But if the price is great on this, look it never hurts to have a spare helmet does it?

Not a fan

  • Familiarity: I returned this product before using it
  • Fit: True to size

I have a Giro Atmos and assumed this would fit well too, but the helmet hits the top of my head and the webbing is slack on top and comes too close to my ears. The chin strap buckle is positioned almost all the way to my right jawbone because unlike other helmets the straps don't slide in the back and instead are permanently attached. It looks nice on, but I don't think it would be comfortable for long rides unless I added extra padding on the top. I haven't ridden with it as I plan to return it, so can't comment on its aerodynamics.

Avg. ride time: 3h 52m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

great design and fit

  • Familiarity: I've used it several times
  • Fit: True to size

I initially looked into this helmet because of the claims of saving some wattage from its aero design without looking like some pointy aero helmet. I was at a LBS, saw the helmet and put it on. Fit perfect right off the bat and was very light. That pretty much did it for me. Once bought I adjusted the chin strap maybe twice to find my sweet spot and that has been it. Love the fit and it does not slide down after a while. It does seem to be a little quieter as in wind noise from my prior Bell helmet. It is way more comfortable than my prior helmet and is so light you just about forget about it being on. Consider me a fan. *Update*. I have on several occasions right after starting my ride thought I had not put my helmet on because I don't feel it to then realize that I do in fact have it on. Can't get more comfortable than that.

Giro's best helmet in a long time

  • Familiarity: I've put it through the wringer
  • Fit: True to size

Complete package. Reasonably light weight, very comfortable fit, easy to use retention system, well ventilated. And if you believe Giro, its aero as well. Having tried most other high end helmets, i went with the Synthe as it does everything well and looks great to boot.

Giro Synthe helmet

  • Familiarity: I've used it several times
  • Fit: True to size
  • Size Bought: Small

The best I've ever owned! Lightweight, comfortable, stylish, reasonable price...I am extremely pleased with this superior Giro product and you will be too!!

Avg. ride time: 4h 52m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

The best fit goes one step better.

  • Familiarity: I've used it several times

I was a huge fan of the air attack. Not because of goofy looks but the fit! The Roc Loc Air, which was introduced on the Air Attack, is seamless and reduces all pressure points on the front of your head.

Where the Synthe goes one step further is introducing more ventilation holes on the exterior, while still maintaining the aerodynamic feel which originated on the Air Attack. From high speeds to low speeds, air can enter, and exit, leaving your head feeling happy during summer months.

Avg. ride time: 57m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Better than expected

  • Familiarity: I've used it several times

I've owned a few different Giro helmets, I expected it to be like the rest of them but with a sleeker design. I feel like this helmet is not only lighter but breathes better than any others that I have owned. The helmet works great with my Smith PivLoc Arena Max glasses. They fit just fine into the front holes when climbing or needing a place to stash them during the ride.

Has anyone tried the Giro Synthe with the Smith Piv Lock sunglasses? Wondering if it's a better hold than the Aeon?

Best Answer

I use the Synthe with the V2 Max and the V90 Max. Both are fine when worn (no touching/rubbing), but the V2 Max won't stay secure in the front holes on climbs, etc.

Avg. ride time: 4h 59m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Great - So Far

  • Familiarity: I've used it several times

I haven't crashed with this helmet, so, I can only comment on the other aspects like fit, comfort, weight, aero, etc. if any of those are important to you, this helmet will not disappoint.

Update after 1,500 miles: The forehead pad is a little touchy in that it is precisely the right size to cover the plastic indo-skeleton. This is nice until you bump the helmet and the pad moves and exposes the plastic to your forehead. Minor annoyance that could be resolved with a slightly bigger pad.

How similar is the fit to the Aeon? I have a big ol' melon, and a large Aeon will do the trick, just barely, with the dial mostly out, and the vertical adjustment at maximum.

Joseph, I think that you will need to try it. The Aeon does not work for me, but this one does. But that can't really be your guide I think. You really should go to your local bike shop and try this specific helmet, it fits differently

Avg. ride time: 3h 44m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Why did this take so long?

  • Familiarity: I've put it through the wringer

This is without a doubt the best bike helmet I've ever owned. It loses no cooling to any of the previous "non aero" models, the fit is just as good if not better than anything else in their lineup & it's FAST. Anything over 25 MPH & you'll notice a difference and, as drag squares with speed, above 30 this thing really sings. Gold Star Giro, Gold Star...

Avg. ride time: 2h 19m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Best Giro helmet by far

  • Familiarity: I've put it through the wringer

I have mostly owned Giro helmets over the years, and the Synthe is the best design ever. I have had mine since January and it is still the best fitting, most comfortable yet. The overall retention system holds your head just away from the foam liner instead of using pads making it cooler and more conforming to your head shape. The liner has a micro adjust function that allows fine tuning of the fit. Maybe I have an odd skull shape but before I have had to always slightly reshape and smooth the Styrofoam liner on most Giro helmets I've owned. With the Synthe, it feels like a custom fit. Although most compare and strive for the aero, style and weight statistics, fit and comfort are at the top of my list. Try one on your head and you'll agree. A 5-star helmet.

Tri helmet replacement

  • Familiarity: I've put it through the wringer

I have been using one of those sci fi looking aero helmets. It never felt right and was hotter due to the lack of vents.
The Synthe feels great on my head...lots of protection and cooling.....not cheap but it is worth it.