I have a good sized melon, and the large is a perfect fit. I looked at Pok helmets, but decided the styling was a bit odd. the Giro design felt like it would age better. This is my second Giro helmet, and the fit is similar. I'd say it's a more comfortable helmet than my previous one, with one exception. Maybe it's the nature of MIPS, but the air flow isn't as good. I'm getting used to it...or maybe the weather is just getting cooler. Overall, I'm very happy with it. Good purchase, no regrets.

I read reviews and was set to spent $200+ for a Giro Synthe MIPS helmet. Then, I tried one on. I couldn’t believe such an expensive helmet with incredible design features would have such a cheap chin strap. A nylon/polymer strap!!! The strap was uncomfortable and I would bet would be chaffing and irritating. I was expecting leather or at least synthetic leather. Needless to say, i’ll Choose a different helmet.

Super comfortable, reliable Giro fit. Straps easy to adjust, fit wheel works well. Disappears on my head.

It's a nice helmet for sure, but I expected a bit more. I've always had Giro helmets and it was time to replace my old one, so after looking around, I settled on the Synthe. I would have thought that a fairly high end helmet would have some significant improvements over the 10 year old model it was replacing, but... not really, besides maybe MIPS, although I hope I never put that to the test.

And, irritatingly, the smaller sweat pads seem to channel more sweat to the middle of my face/glasses/nose than the old helmet did.

I have been wearing the Giro Synthe helmet for years. It's great, looks good, is light, comfortable and not hot to wear. However, for the new MIPS version the Sythne in size small is smaller than the non-MIPS small. I have always worn a size small Sythne with a cycling cap under it. But this MIPS version of the Sythne is a smaller small, I can't wear a cap under it like I normal do. I had to return it.. Just fyi for those looking to replace their Sythne helmet in size small, like I was.

I have used Giro synthe helmets for a few years. My last one's liner just cracked due to a crash so I replaced it with this MIPS system. Great helmet - ventilation is superb. You may need to go up a size because of the MIPS insert. I ordered a medium and had to return it for a large - no hassle from CC. My only issue is that no one seems to make the replacement padded insert which goes at the front of the helmet. The original pad is fine, but after washing off the sweat a few times, it falls apart.

I haven't actually used this quite yet, haven't been able to go for a ride yet this year, but looking forward to it! This seems like a really good helmet, incredibly lightweight and comfortable when I have just tried it on! Will update with more information when I get the chance to use it!

I tried on the Zephyr and several others, and this one is very comfortable and easy to wear. Perfect helmet. Lightweight but his MIPS protection, and it'c comfortable.

I’ve used Giro for many years and never disappointed. At first I was a little skeptical about the MIPS due to fit issues, but once worn it feel nice and easy to adjust.

I love the Giro Synthe. I own both MIPS and non-MIPS versions now. I can confirm that the MIPS version fits just slightly, slightly smaller than the non-MIPS version. So if you're on the fence sizing-wise, go with the larger size.

I love the aerodynamics and quietness of this helmet. If you compare the Synthe to previous top all-around road helmets (S-Prevail, Giro Aeon, Giro Ionos), helmets I rode in for years, there is no comparison. The Synthe is significantly quieter, especially when you put your head down during hammertime.

By the way... Greg van Avermat won the Olympic Road gold and the 2017 Paris-Roubaix wearing... the Giro Synthe helmet.

I've tried several helmets this year, and I've landed on this one and am very happy. It looks pro because some of the racers in the world tour peloton use this helmet. It's lightweight and has the added bonus of being a MIPS helmet.

Initial ride was 5 hours, hot, humid, and rainy at times.
6-12% grade hour long climb it didn't get too hot.
10 minute 40mph descent it didn't get too windy.

When I first pulled this helmet out of the box, and saw almost no padding whatsoever inside and no extra padding in the box, I thought for sure that my review was going to end up being a negative one, and yet it isn't.

Giro's current top end road helmet (I'm not counting the Vanquish aero helmet), is one of the lightest and most comfortable I've ever had the opportunity to wear, because while the padding is minimal, it's perfectly situated.

A lightweight helmet is really important to me as well. I have degenerating discs in my neck, and relatively weak muscles. Because of this, any extra weight on my head can put stress on my neck muscles when trying to hold my head up in riding position. On today's inaugural ride in this helmet, I barely noticed the weight of the helmet at all.

My lack of fitness, on the other hand, I noticed right away, and while there were lots of times I was struggling on the bike, none of them were neck related. To me right now, that's worth a 5-star review.

And the added benefit of MIPS protection would bump it to a 6-star review if I had that option.

The helmet was awesome in every way but was too small so I returned it. I purchased it on sale, size small (clearance?) and it's definitely worth it if you have a small head.

Bought this helmet as a gift. Here is what they had to say about it - "One of the best helmets I have ever used. The fit is great and the ventilation is really awesome. Very comfortable even after hours in the saddle. I've been using this helmet for road rides, road races, and cx races. Love knowing I have the extra protection of MIPS."

I used this helmet for a year and a half to two years and it has been exceptional. The small size fit my 21.5" head perfect and when I recently had a bike crash it kept my head safe and it did not move from it's original position at all.

I loved my original Synthe Titanium and rode it for several seasons. Had to replace it after a crash in the fall and decided to upgrade to the MIPS for extra safety. Fits exactly the same as the original and breathes just as well. I don’t plan to ever switch from this helmet except for future renditions. Couldn’t care less about the Aero claims, but I guess it’s a plus.

I couldn't decide if I wanted to put that much money in a helmet, but I am glad I did. Researched several different helmets and finally decided on the Giro Synthe MIPS. I have been wearing a Giro Atmos II and wanted to get a helmet with MIPS. It is one of the most comfortable helmets I have worn and is very easy to adjust. The helmet looks great and I could not be more pleased.

Great colour. Helmet is nice and light. I also have a Foray and this fits the same. The Synthe is a beautiful helmet and has MIPS but I'd have to say the cheaper Foray is much the same as the Synthe and way better value. I had a crash with a Foray and wrote the helmet off but my head was good and the Foray didn't have MIPS. Personally I'm not so sure that MIPS is the great miracle life saver but maybe it is.