Best All-Around Premium Road Bike Helmet of 2021

The Giro Synthe is a premium road bike helmet aimed at bringing all of the features that you want in a race day helmet to a helmet that is comfortable enough to be worn every time you throw a leg over your bike. While this might sound like a tall task, the Giro Synthe MIPS road bike helmet lives up to its rather lofty ambitions in almost every way.

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See Our The Best Road Bike Helmets of 2021: Cycling Helmet Review!

Comfort, Fit, and Adjustability

A look at the outside or inside of the Giro Synthe road bike helmet might lead you to believe that this would be a helmet reserved for race days. However, actually wearing the helmet reveals that this idea could not be further from the truth. The Synthe is among the most comfortable helmets that we have ever worn, and you would be hard pressed to find anyone who disagrees.

The Giro Synthe uses a Roc Loc Air fit retention system, which we have reviewed fondly in mountain bike helmets in the past. Unlike most helmets, the Roc Loc Air fit system keeps the inner eps foam of the helmet suspended away from your head, which increases the helmets ability to keep your head cool.

Furthermore, most helmets’ retention systems attach to the helmet near the temples. This means that running the helmet on the tighter side can cause it to shift forward on your head, and even cause uncomfortable pressure points near the temples. However, the Giro Synthe’s Roc Loc Air fit system wraps all the way around your head, allowing it to comfortably fit a much wider range of head shapes than most road bike helmets.

The Giro Synthe is further adjustable via the very minimal Y buckles, which allow you to dial in their fit around your ears.

Overall, the Giro Synthe features top-notch adjustability and fit for the widest range of head shapes of just about any road bike helmet in our review.

Weight

Weighing in at 268g, the Giro Synthe is a lightweight road bike helmet, particularly for one equipped with MIPS.

Ventilation

The Giro Synthe MIPS boasts 26 vents and is an extremely well-ventilated helmet. In fact, we rank it only just behind the class-leading Lazer Z1 MIPS and POC Ventral Spin in this category. The Roc Loc Air fit retention system keeps the helmet suspended away from your head, allowing more airflow than most helmets. However, the Giro Synthe MIPS’ 26 vents are smaller than those found on the most highly ventilated road bike helmets that we reviewed, and this means that, particularly at slower speeds, it falls just behind those helmets that were top notch in this category.

Safety Tech and Additional Features

The Giro Synthe MIPS uses a standard MIPS insert as well as in molding, which are both fairly standard for top of the line road bike helmets, where there is little separation among the top contenders. 

Meanwhile, a sunglass perch is a nice addition to the Giro Synthe, as anyone who has ever lost a pair of sunglasses while trying to thread them through their helmets vents can attest.

Aerodynamics

While we don’t have a wind tunnel on hand for testing the Giro Synthe certainly looks like an aerodynamic road bike helmet, and we know that Giro put it through extensive wind tunnel testing to make sure that it is as aerodynamic as it looks. Furthermore, you would be hard pressed to find a more aerodynamic helmet that you would be keen to ride in every day.

The Bottom Line

A lightweight, aerodynamic helmet that is well ventilated and comfortable enough to be your daily go-to helmet for both training rides, as well as races, sounds just about too good to be true, but the Giro Synthe MIPS helmet really does pull it off, earning our top pick for the best all-around premium road bike helmet of 2021. Furthermore, it can frequently be found on Backcountry for less than $200, making it quite the steal to boot.

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