Best Bike Helmet of 2021

Best Overall Road Bike Helmet with a Volumnious Fit

Giro Synthe MIPS

Weight: 336-grams | Diameter Range (size L): 58-62 cm

The Giro Synthe MIPS earns consistently high scores in nearly every rating metric with its exceptional comfort, lightweight design, and semi-aerodynamic shape. We love how the Synthe is light and slightly more aerodynamic than other contenders. We've found that the Synthe has a slightly higher-volume fit with more room in the forehead area for those with larger nogens that need protection. If you seek great comfort with decent ventilation and an aerodynamic design, this is the one to consider.

One potential shortfall with the Synthe is its exposed EPS foam on the lower part of the helmet brim, which could potentially be damaged if dropped or scraped against. While this weight-saving design feature is not uncommon with other models in the lineup, it just means you'll need to give your helmet a little extra care during storage and transport. With one of the lowest weights in the lineup and a built-in MIPS liner for improved crash protection, the Synthe is a high-performance training and racing helmet that is consistently among the best of the bunch.

Read review: Giro Synthe MIPS

Best Overall Road Bike Helmet with a Less Volumnious Fit

Bell Z20 MIPS

Weight: 312 g | Diameter Range (size L): 59-63 cm

With its luxurious comfort, excellent ventilation, and classy high-end style, the Bell Z20 MIPS is another favorite. It features similar performance to other high performers but features a different shape that some may prefer. It has both thick padding and excellent ventilation which offers comfort throughout the season. It has a sharp-look with top of the line features that rate highly in every scoring metric. The fit of this helmet has a flatter slope on the front of the helmet that accommodates a less voluminous head and shorter forehead.

While the Z20 is a very comfortable and high-performing helmet, it is slightly heavier than some other top-tier competitors, weighing in at 336 grams in a size large. While this is a slight weight penalty for such high performance, we are only talking about 20-30 grams overall. The Z20 is one the expensive side but its price is in line with market pricing for a flagship helmet providing top of the line features.

Read review: Bell Z20 MIPS

Best Bang for the Buck

Giro Agilis MIPS

Weight: 336 g | Diameter Range (size L): 59-63 cm

The Giro Agilis stands out as one of the highest performing helmets in the entire lineup at any price point. The Agilis has one of the most comfortable designs that we've tested with an excellent full circumference headband with an integrated MIPS liner that comfortably cradles the head, as well as just the right amount of padding in just the right places. In our opinion, this model is as comfortable as any other helmet that we've tested. The full-coverage polycarbonate shell material fully encases the EPS foam liner for extra durability, with hardly any of the sensitive foam material exposed. All of this performance comes with one of the lowest list prices in the lineup, making it of tremendous value.

While the Agilis impresses with its comfort, adjustability, and durability, it does lack some ventilation and comes in at a slightly heavier weight. Its design, with a full-coverage polycarbonate shell, also doesn't feel as sleek and high-quality as some of its comparatively more expensive competitors. However, we think these are reasonable sacrifices to make to save a good chunk of change off the list price of many of the top-tier models. We think most riders will be totally happy with this helmet, and it comes highly recommended.

Read review: Giro Agilis MIPS

Best for Aerodynamic Performance

Kask Infinity

Weight: 408 g | Diameter Range (size L): 59-62 cm

The Kask Infinity features a sleek design that uses a unique retractable door which opens up for extra ventilation or closes to provide a smooth and streamlined profile. This helmet makes an excellent choice for riders looking to do a lot of solo breaks, sprinting, and maybe an odd time trial, but doesn't want to completely sacrifice ventilation for improved aerodynamics. The Infinity also has a thick padding system that helps draw moisture away from the head in warmer weather and helps insulate in cooler weather. The upside is that this makes cold weather riding more comfortable with the close-able vent and roomy headcase that fits a warm cap or beanie

Unfortunately, with the extra padding (mentioned above) this helmet can get toasty in the winter. In addition, while its ventilation is certainly noticeable, the ventilation performance doesn't quite stack up to that of fully adequately ventilated road helmets. If you tend to do most of your riding when the mercury rises, you may want to look into a better-ventilated option, which typically means giving up some aerodynamic qualities. If you are set on an aero profile but want a flexible design with reasonable ventilation, you'll have a hard time finding a better performing model.

Read review: Kask Infinity

Best for Lightweight Ventilation

Lazer Z-1 MIPS

Weight: 305 g | Diameter Range (size L): 58-61 cm

The Lazer Z1 MIPS earns recognition for its incredibly lightweight design and noteworthy ventilation. It features 31 vents that are large and placed exceptionally well, keeping your head cool when you begin to sweat. Its 305-gram weight (men's size Large) is among the lightest helmets in our lineup with a built-in MIPS liner. With comfortable padding and a unique headband adjustment dial on top of the helmet, there's a lot to like about the Z1.

Although the Z1 MIPS stands out for its high-end ventilation, its lightweight design definitely doesn't feel as substantial and durable as other models. While this wouldn't impact the safety and crash protection capabilities of the helmet, it could potentially compromise the long-term durability. Also, the adjustment dial on top of the helmet, while unique and perfectly serviceable, does take a little bit of getting used to, and some riders may prefer a more traditional design.

Read review: Lazer Z-1 MIPS

Why You Should Trust Us

To test road bike helmets, we enlisted the help of Nick Bruckbauer and Ryan Baham. Nick likes to spend his weekends grinding away in the mountains above Santa Barbara, CA, and Ryan is an avid road east-coast road cyclist who regularly ticks off 100+ mile rides.

After selecting the top-performing products on the market, we put our lineup of helmets through the wringer. We poked, prodded, and weighed each model in our lab, and then took them out on a whole lot of bike rides through a wide variety of conditions. These helmets were subjected to sweltering heat, heavy rains, frosty spring adventures, up some grueling climbs, and down some blazing descents.

Related: How We Tested Road Bike Helmets

Analysis and Test Results

We chose helmets that are best for road biking. While all of the helmets meet the same safety standards set by the U.S. Government, construction methods and design features vary by manufacturer and model. Each model is scored on five important metrics, including comfort, adjustability, weight, style, ventilation, and durability.

Related: Buying Advice for Road Bike Helmets

Value

To help you find the best balance between price and performance in your next road bike helmet, we rated each helmet in our lineup against the competition and mapped out which models represent the best overall value. The Giro Agilis offers high-end performance in a very affordable package.

Comfort

Road cyclists often spend long days in the saddle for both training and racing, making a comfortable helmet a crucial piece of equipment. Ideally, your helmet should "disappear" once you put it on and shouldn't cross your mind during your ride. While head sizes and shapes are extremely variable from rider to rider, our testers consistently found certain design features that helped a helmet adapt to different heads, adding to the overall comfort regardless of the user.

Our testing revealed that padding design, full circumference headband adjustability, and chinstrap design each played an essential role in overall comfort. Quality padding is crucial, especially in the forehead and temple areas, because the headband adjustment systems on most helmets tighten in the back, pushing the head against the front of the helmet. While quality padding is a critical component, we found that the location and coverage of the padding and the shape of the foam liner were more important than the thickness or density of the padding itself. For example, the Kask Infinity has some of the thickest, most luxurious pads out of any helmet we tested, yet is outscored by the Giro Synthe MIPS in our comfort ratings. The Bell Z20 also strikes a nice balance between padding density and coverage, and a comfortable cradling by the headband for a snug, secure fit.

All of the helmets we tested have internal headband systems that allow adjustment to fit various head shapes and sizes. The best designs are those that make a complete loop around the head, rather than those that do a partial loop and anchor into the helmet liner near the temples. The Giro Agilis has a newer Roc Loc 5.5 headband system that integrates the MIPS liner into the headband and cradles the head for a snug, customized fit. The adjustment systems on the Giro Synthe MIPS, Bell Z20 MIPS, and Giro Aether MIPS also wrap entirely around the head, earning these models top scores in this category.

Chinstrap design also plays a significant role in helmet comfort. Our testers preferred helmets that incorporated thin webbing straps and a Y-buckle, allowing the straps to lie flat against one's face. The Specialized models and the Giro models use different strap designs, but models from both of these brands stand out with thin, supple webbing material and well-designed Y-buckles that allow the webbing to lie flat.

Overall, the Giro Synthe MIPS, Kask Infinity, and Bell Z20 MIPS stand out as the most comfortable models that we tested. These helmets all have the best combinations of sufficient and well-placed padding, full circumference adjustable headband systems, and comfortable chinstrap systems.

Adjustability

A helmet must fit well to be comfortable and to function as designed. For a helmet to protect you, it must stay on your head. Correct fore/aft positioning, headband tightness, and chinstrap tension will help ensure that your helmet stays squarely on your head and is ready to protect you when if you ever need it.

All of the helmets in our lineup have a chinstrap system with one strap behind the ear and one in front, where the straps are joined below the ear with a plastic Y-buckle. On most helmets, the Y-buckle allows the straps to be adjusted to change the height of or the tension between the front and rear straps. Models with an adjustable Y-buckle typically scored higher in the adjustability rating metric. Despite its lack of an adjustable Y-buckle, the Specialized Airnet seems to have the ability to fit a broad range of heads while maintaining equal tension on the front and rear straps. The Kask Protone is the opposite - the lack of adjustability was a deal-breaker for some testers who could not achieve equal tension on the straps. Some models have strap designs that feed through the helmet's liner to provide more side to side adjustability, while others have straps that are permanently anchored to the liner.

Each helmet has an adjustable dial near the back of the helmet to adjust the fit and the tension of the helmet's headband. The Lazer Z-1 MIPS has a unique design where the tension dial is at the top of the helmet. While he internal headband sizing varies between manufacturers, most medium-sized helmets we tested offer 4-6 cm of size adjustment and fall somewhere in the 52-60 cm size range, and most large models offer 2-4 cm of size adjustment and typically have a 59-63 cm size range.

While the tension dials on every helmet function as intended, some are on the smaller side such as on the Giro Synthe MIPS, and some or partially hidden like on the Kask Infinity or Lazer Z-1 MIPS, potentially making them a little harder to work with while wearing thicker gloves or with cold hands. Our favorite dials have 360-degree accessibility, like on the Bell Stratus MIPS, which are large enough to be adjusted while wearing gloves or with numb fingers.

Each helmet in our lineup also has fore and aft adjustment on the headband system, typically offering between 2-5 cm of adjustment. None of the fore/aft adjustment mechanisms are particularly easy to adjust, but once set, they should stay in place and provide a snug fit without any further tinkering. Some of the adjustment devices are buried under the MIPS liner, making an adjustment even more difficult as is the case with the Lazer Z-1 MIPS. We prefer an exposed adjuster like what is seen on the Giro Synthe MIPS.

Weight

Road cycling is a gram-conscious sport where both professional and amateur riders go to great lengths to decrease their riding weight. Every extra gram can slow you down on climbs, and a heavy helmet can also cause neck fatigue on a long ride. While helmet weight can certainly impact comfort, all of the helmets we tested are relatively light compared to the overall marketplace, so these comparisons are relative to the models tested in our lineup.

We weigh each product ourselves to get an objective comparison, as the manufacturer claimed weights can often be inaccurate. We're happy to report that every helmet we measured was within 5% or less of the claimed weight, which is essentially equivalent when accounting for potential measurement tolerances and precisions.

Interestingly, some of the more expensive products we tested like the Kask Infinity are heavier than some of their more affordable counterparts. There are several factors for this. Many of the higher-end helmets have more polycarbonate shell material covering the EPS foam liner, which marginally increases weight but also increases durability. Most helmets in our lineup also include an internal MIPS liner for additional crash protection, adding 20-30 g to their non-MIPS equipped counterparts. We feel that the modest increase in weight for a MIPS liner is outweighed by the potential safety benefits. More aerodynamic helmet styles like the Kask Infinity or the Specialized S-Works Evade typically have a longer profile and fewer vents, which increases the helmet material and the overall weight.

Style

The aesthetic appeal of a road bike helmet is subjective because, as they say, beauty is in the eye of the beholder. However, many of the helmets in our lineup have unique design features that aren't really accounted for in any other rating metrics. This is where we shine the spotlight on features like rubber sunglass holders, retractable vents, or distinctive aesthetics.

The Bell Z20 MIPS scores highly in our style ratings, thanks to its sleek and flowing design, modern two-tone matte color finishes, and contrasting strap colors. The Kask Infinity also stands out in this category with its nifty retractable vent system, as does the Bontrager Ballista with its stealthy shape and matte black finish.

Ventilation

A well-ventilated helmet helps keep your head and core temperature down, helping enhance comfort and performance. As aerodynamic designs become a higher priority for helmet manufacturers, balancing aero design with ventilation has increasingly become a challenge. The best-ventilated helmets are not necessarily those with the most vents, but rather the ones that pair properly placed vents with internal channeling for optimum airflow. Aero helmets such as the Kask Infinity, Bontrager Ballista, and the Specialized S-Works Evade have fewer vents and tend to be hotter, especially at the low speeds often experienced on a steep climb.

The Specialized Airnet is one of the best-ventilated road bike helmets that we tested. Air movement and heat evaporation are quite noticeable thanks to 21 well-placed vents. On some helmets, the internal MIPS liner can block some of the vents, but that's not an issue with the Airnet. The MIPS liner aligns perfectly with the vents, and there is no airflow restriction. Another standout helmet is the Lazer Z1 MIPS, that packs 31 vents into one of the lightest helmets in our lineup. The lightweight POC Octal also impresses with its aggressive vent design, and the lack of a MIPS liner enhances airflow within the helmet.

Lower scoring products, such as the Bontrager Ballista and Specialized S-Works Evade can be stiflingly hot on even moderately warm days. While aero helmets typically sacrifice ventilation for a sleeker profile, the Kask Infinity scores reasonably well with its retractable vent cover that gives the option of switching between more ventilation or more aerodynamics.

Durability

The EPS foam found in most helmet liners is a relatively soft material that is prone to dents and abrasion.

The most durable road helmets have a protective polycarbonate shell that extends down around the base of the foam liner, leaving very little of the liner exposed. Helmets with this type of full-wrap shell tend to get banged up less during everyday use. However, many helmet manufacturers choose weight savings over enhanced shell coverage. No matter how well a helmet is constructed, they are typically one-hit-wonders when it comes to a crash impact, so our durability assessment identifies the ability to withstand daily abuse and accidental bumps and scrapes.

The Giro Agilis and Kask Protone find themselves at the top of the pack in our durability ratings, with almost no exposed EPS foam on the exterior of the helmet. The polycarbonate shell extends around the base and covers nearly the entire upper portion of these helmets. The Specialized Airnet also receives high marks, with a wraparound polycarbonate shell that protects the helmet base, but has a bit more EPS foam exposed on the upper portion than the top scorers.

Conclusion

The primary purpose of a bike helmet is to protect your head in the case of a crash, and all helmets sold in the USA are subject to the same minimum safety standards. While all helmets may offer the same basic level of crash protection, beyond that, they are far from equal. Different helmet designs go above and beyond by adding extra features such as MIPS liners for extra safety, adjustable headbands and chinstraps, comfortable padding, and different levels of ventilation. Our testers racked up hundreds and hundreds of miles in the saddle, through all sorts of conditions, to sort through the differences in each helmet to help you find the best model for your next ride.