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Review: Giro Prolight Cycling Helmet

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BIKERUMOR REVIEW: Giro’s Prolight helmet made its re-introduction at last year’s Tour de France on a few select sponsored teams, and it became generally available this spring.  I’ve had a chance to check one out for the last two months, and I can sum it up by saying “You’re gonna want one of these.”

The qualifier to that remark is “if you’re a roadie or XC mountain biker.”

When it was first announced, the claimed weight was 175g.  I’m assuming the CPSC had some things to say about that, because the new claimed weight for a Medium is 195g…which is still insanely light.  My test model weighed slightly less than that, too.

In a nutshell, the Prolight uses more vents (25) than Giro’s top-of-the-line Ionos (21), and it costs $30 less ($200 vs. $230). Though they’re smaller holes, they use similar internal channeling to keep your head cool, and it does a great job of it.  Part of the gram shaving comes from their all-new RocLoc SL retention system, non-adjustable straps and a minimal chin clip.

Check out all the details and full review after the break…




Your purchase includes the helmet, in your choice of Black, White, Blue/Black or Red/Black, and extra pads, a sticker to write your name and vitals on and presumably adhere it to the inside of the helmet, and instructions/legalese.  The helmet also has several tags attached to it explaining the features, which we’ll get to here:



First up, the all important weight.  Claimed weight, as you can see here, is 195g.


Actual weight on the Park Scale: 193g.


The side straps aren’t adjustable where they meet like most helmets.  The fabric used is very lightweight.


The padding inside is pretty thin and sparsely placed.  They contain X-Static threads, which use 99.9% pure silver to prevent bacteria from growing and funkifying your helmet.  It also (claims to) help regulate temperature and eliminate odor and static.


The clip bucket and strap retention system are adjustable, and they’re quite minimal.  The sliding retention bit on the end of the strap is pure brilliance…it replaces the “rubber band” that other helmets use to keep the straps from flapping around.  Because there’s only one strap sliding through the buckle, too, it’s far easier to adjust.


Additional adjustability comes from the front of the RocLoc SL plastic webbing.  Hidden under the side padding are three snap holes.  Simply pop the plastic webbing out and put it where you want it.  My noggin measures about 58cm to 58.5cm, so I placed it on the rear-most hole.


Borrowing a photo from Giro’s website, this perfect studio side shot shows just how thin the webbing is.

Another trick for feathering the weight is using In-Mold technology, which essentially fuses the outer hard candy shell to the impact-absorbing EPS liner.  Because they’re fused into a symbiotic “exoskeleton”, they reinforce one another to create a stronger overall package.  1 + 1 > 2.


On the back, the stretchy sweatband-like material creates the “self adjusting” retention system.  It’s placed on the fabric straps such that it pulls in just under that bump at the back of your skull, which keeps the lid in place and prevents it from rocking forward and back…which provides the perfect segue into:



The RocLoc SL system is by far the most comfortable retention system I’ve used.  The first time you put the helmet on, it feels a little snug, but once accustomed to the feel, it’s amazing.  There’s no helmet movement, no fore-aft rocking and no bulky plastic buckles or dials.

I’d like to think my head is average in shape and size, and the side straps meet perfectly under my ears.  As with any lightweight helmet, there’s more of a gap between the top of the ear and the start of the helmet…and rear coverage doesn’t do much for the lower section of the skull…which is why I put the caveat in this review’s intro:  If you’re into all-mountain, freeride or are accident prone when you hit the dirt, you probably want a helmet with more coverage.


I rode the Burnsville Metric Century Ride in April with a Walz Cap underneath, and it accommodated the cap perfectly.  Once the sun came out and started baking everything, I pulled the cap off and my head stayed plenty cool.

Today, I started a ride just as the rain started (and stayed with us for the first hour), and ended with sunshine.  The padding didn’t retain any moisture, dried exceptionally quickly and those salt stains washed right out of the straps.  In fact, even the straps dried extremely quickly.


On any ride, a lightweight helmet is great.  On longer rides, it can really help reduce neck strain…especially for “journalists” like me that sit in front of a computer, often craning forward to examine bike photos…but anyone that spends any appreciable amount of time at a desk will especially appreciate the reduced weight.

The other benefit is the emotional whalloping you’ll give your friends, my conversations typically went like this:

TYLER: Check this out (I hand them the Prolight).

THEM: (accepting helmet, floating it up and down in their hand) “Holy $&%#” or “Oh my God.” or “You suck.”

After that, they’ll be disappointed with their crappy helmets and you’ll have a mental edge.

One last thing worth mentioning is that the helmet stays in place with a light/camera mounted to it.  Because the stretchy RocLoc SL strap on the back actively pulls the helmet into place (without, I should add, creating any pressure points), it helps keep everything in place when putting heavy objects on the top.  On one night mountain bike ride with a Light & Motion Seca strapped to it, the Prolight didn’t flop forward or move around like some other helmets do.  I said it before and I’ll say it again: I’d be very surprised if other helmet manufacturers don’t mimic this retention system…it’s fabulous.


Short of intentionally crashing in it or conducting my own smash tests, I’ll assume that because it passes the required tests, it’s protecting my dome as well as any other lightweight lid.  Therefore, there’s absolutely nothing bad to say about the Giro Prolight.  It’s crazy light, to the point where it really feels like you’re wearing nothing at all, super comfortable with no pressure points or tightness, the straps and pads wick dry in an instant and the buckle/strap retention on the chin is the best I’ve ever used.  Unless you need extra coverage for doing dangerous things among rocks and trees, make this your next helmet.  A full, enthusiastic Five Thumbs Up!


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13 years ago

“Symbiotic”? Used just like the manufacturer would want you to. So much for “journalism.”

13 years ago


i own the same Helmet in Black in it weights in size M 169 gramm ! (claimed 173 gramm, production Date December 2009)


13 years ago

Robin, I fail to see how Tyler’s use of a word you perhaps don’t recognize in a manner you deem inappropriate for the article correlates to poor journalism. Please clarify.

13 years ago

Hello Tyler,

thanks for your explanation ! Thanks Giro … ..i’m from germany…


13 years ago

Just bought and rode with this helmet for the first time today. In short, it is as good as the review says.
Didn’t really do any research ahead of time so I kind of stumbled on it. I’ve always taken the approach that a helmet is a helmet and just gone out and bought a $50-60 one. Others that I’ve owned have had a bunch of moving plastic parts, been OK but not terribly comfortable, and sloshed around on my noggin when out of the saddle. The helmet I was replacing was a Giro Transition.
I finally figured I’m putting on enough miles I’d get something maybe a little more comfortable and lighter. When you put this helmet on, its feels like you have a baseball cap on, but more airy. It doesn’t move around when you are out of the saddle. And man, it is so light you really just have to try it on to believe it. It was a hot day, and the vents kept me way more comfortable than my old helmet.
Sure, its expensive. But I asked real nice for a “deal” (Its my local shop where I drop a lot of dough throughout the year) and they gave me a 20% discount. That sealed the deal. Try one if you get the chance.
Now I have to go watch the end of the prologue.
Happy riding.

13 years ago

Meant to say Giro Transfer, not transition in previous post.

Rose Marie Ray
13 years ago

I wear a women’s “small ” Giro Pneumo and also have a Garneau “small” aero helmet. I Recently crashed and cracked the inside of my Pneumo and ordered a Prolight over the Internet. I am disappointed in it because it cannot be adjusted in the back nor in the chin strap to properly fit me. The only way I will be able to make it work is to sew the chin strap so that I do not have a loop sticking up from the non-adjustable clip and pull in the elastic in the back to be more snug. I may just try to return it for a traditional helmet from Giro with adjustable front and back.

Bari Wood
Bari Wood
13 years ago

I have tried this helmet in small and medium and the fit is terrible. I am a smallish woman with a average size head for my size. The helmet continues to slip off if I give it a good shove – which is what would happen in a crash. When pulled tighter, it hurts the front of my head and leaves indentations. Someone said I looked lie a forecepts baby. Yes the helmet is light but with the fit so awful, who cares. I am going with the Specialized Prevail -much better fit and fully adjustable. Giro cut too many corners on he lack of adjustability to gain 10grams. A real stinker!!

12 years ago

I crashed heavily last weekend with my head hitting the road very hard. The helmet provided outstanding protection. Replacement is ordered already.

11 years ago

I have the Prolight bought off a friend who didnt use it once and before that I didn’t own a helmet so I cannot compare it against anything.

I have the small version which I weighed at home on electric kitchen scales and it weighed in at 160-165g (can’t quite remember which)

I can hardly remember the helmet is on my head when I am out riding. It ventilates brilliantly and feels really comfortable. I always sweat loads but with the helmet I sweat a lot less and even with hours in the saddle does not feel uncomfortable. I would not switch to any other helmet and at half the cost of some of the other top of the range Giro and Spec helmets it’s well worth the money.

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