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Best Mountain Bike Helmet of 2021

We tested models from Giro, Specialized, POC, Smith, and more to find the best mountain bike helmets
Photo: Zach Wick
Sunday November 7, 2021
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Trying to decide on the best new mountain biking helmet? After researching over 80 models, we purchased the 23 best available for side-by-side testing and comparison. With all the options out there, finding the perfect helmet can be challenging, and this purchase is one of the most important things you can wear while riding. To help, we spent months riding in these helmets while analyzing every aspect of their performance and design. After thoroughly testing each model, we rated them on six predetermined metrics: protection, comfort, ventilation, features, weight, and durability. We hope this detailed comparative review helps you find the helmet that best suits your needs and budget.

Related: Best Full Face Bike Helmet

Top 23 Product Ratings

Displaying 11 - 15 of 23
 
Awards  Top Pick Award    
Price $300 List
$224.93 at REI
$100.00 at Backcountry
Compare at 2 sellers
$112.50 at Backcountry
Compare at 2 sellers
$160.00 at REI
Compare at 3 sellers
$190 List
$151.99 at Backcountry
Overall Score Sort Icon
80
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78
78
Star Rating
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Pros Adjustable visor, magnetic buckle, magnetic accessory mount, WaveCelMIPS Spherical, adjustable visor, comfortable roc loc harnessComfortable, MIPS, clean look, adjustable visorWell ventilated, adjustable visor, MIPS, good coverageThick EPS shell, goggle and glasses storage, high-coverage
Cons Expensive, moderately heavy, somewhat bulky and bulbous appearanceHeavy, subpar ventilationLong visor, less coverage than some, less ventilation than some, small fit adjustment dialSizing runs a little bigBulky, above-average weight, sweat management
Bottom Line An expensive fully-featured half shell helmet that comes equipped with Bontrager's WaveCel technologyPacked with innovative features, this was the best full-coverage, open-face helmet we testedA good mountain bike helmet, but it was bested by some stiff competition in this reviewA mid-priced helmet from Smith with great ventilation, ample coverage, and a comfortable fitA heavy-duty trail helmet with easy goggle and glasses storage but a bulkier fit
Rating Categories Bontrager Blaze Wav... Giro Tyrant MIPS Giro Montaro MIPS Smith Session MIPS Leatt MTB 4.0 AllMtn
Protection (25%)
9.0
10.0
8.0
8.0
9.0
Comfort (20%)
8.0
9.0
8.0
8.0
8.0
Ventilation (20%)
7.0
6.0
8.0
7.0
7.0
Features (15%)
9.0
9.0
7.0
8.0
8.0
Weight (10%)
5.0
2.0
7.0
8.0
4.0
Durability (10%)
9.0
9.0
9.0
8.0
9.0
Specs Bontrager Blaze Wav... Giro Tyrant MIPS Giro Montaro MIPS Smith Session MIPS Leatt MTB 4.0 AllMtn
Rotational Impact Protection System? WaveCel MIPS MIPS MIPS 360 Turbine
Weight (Ounces, Grams) 16.40 oz, 465g, size Large 1 lb 9 oz, 718g size L 14.11 oz, 400g, size Large 13.36 oz, 379g size Medium 18.77oz, 532g
Number of vents 13 14 16 15 13
Goggle or Sunglasses Integration? Yes Yes Goggle integration Yes Yes
Adjustable Visor? Yes Yes Yes Yes Yes
Sizes S, M, L S, M, L S, M, L S, M, L S, M, L
Certifications CPSC CPSC Bicycle for ages 5+, CE EN1078 CPSC Bicycle for ages 5+, CE EN1078 CPSC, CE EN1078 CPSC, CE EN1078, AS/NZ 2063
Virginia Tech Helmet Safety Rating (if applicable) 5-star 5-star


Best Overall Mountain Bike Helmet


Giro Manifest Spherical


90
OVERALL
SCORE
  • Protection 9
  • Comfort 9
  • Ventilation 10
  • Features 9
  • Weight 7
  • Durability 9
Impact Protection System: MIPS Spherical | Weight: 401-grams (size Large)
Dual-shell Spherical impact protection
Amazing ventilation
Sunglasses storage
Good coverage
Adjustable visor
Average weight
Expensive

In a hard-fought battle, the Giro Manifest edged out some incredible competition to earn our highest recommendation. This unique mountain bike helmet has all of the bells and whistles we would expect from a top-of-the-line, half-shell model in a well-executed, sleek design. Rather than the typical plastic MIPS liner, the Manifest packs Giro's new MIPS Spherical rotational impact system which comprises two separate EPS foam shells connected by elastomers. The shells are made from two different foam densities and are designed to rotate against each other like a ball and socket joint in the event of an angular impact. The interior foam shell drops down low on the back and sides of the head to provide extra coverage for the temples and occipital lobe and fits a wide array of head shapes and sizes comfortably. Large front-to-back vents and interior channels in the EPS provide some of the best ventilation we've ever experienced in a helmet, and the interior padding does a great job of absorbing sweat on those long, hot rides.

We were extremely hard-pressed to find anything to complain about with this model. Performance-wise, we had no issues in testing. The only negatives we can point out are the high price tag and the average weight. With the dual-shell design and all the features we could ask for, this helmet packs a few grams of extra heft over the lightest models we tested. On the trail, however, the difference isn't noticeable with the Maifest's secure fit, and we're not concerned about a little bit of added weight for a do-it-all trail helmet. The price tag might be off-putting at first glance, but it's comparable to the other top-of-the-line helmets in the test. We think the Manifest's performance more than justifies the price tag.

Read review: Giro Manifest Spherical

Best Bang for Your Buck


Giro Chronicle MIPS


76
OVERALL
SCORE
  • Protection 8
  • Comfort 9
  • Ventilation 7
  • Features 6
  • Weight 7
  • Durability 8
Impact Protection System: MIPS | Weight: 410-grams (size Large)
Versatile fit
Durable
Comfortable
Inexpensive
Basic features
Average ventilation

Giro's Chronicle is designed to be a mid-range offering, but it ended up outperforming many of its much more expensive counterparts in our test. The competition was tight, but at less than half the price of some of the heavy hitters, the Chronicle is an excellent value with no glaring weak points. Our favorite aspect of this model was its versatile fit. Giro has decades of expertise and offers a calculated fit for the majority of head shapes. On top of that, the Chronicle sits low on the head for a secure-feeling, high-coverage fit, and the Roc Loc harness system pulls even tension around the whole head. With MIPS integrated into its interior, the Chronicle also provides modern protection and peace of mind out on the trail.

At its low price point, the Chronicle doesn't pack as many features as many other mountain bike helmets we tested. While the features that it does have are well-executed, you don't get the same luxuries, like anti-microbial padding or molded reinforcement in the EPS shell, like Giro's top-shelf models. Despite the limited number and size of the vents, the Chronicle ventilates well, but it doesn't stack up with the best performers in our test.

Read review: Giro Chronicle MIPS

Another Great Value


Bell 4Forty MIPS


77
OVERALL
SCORE
  • Protection 8
  • Comfort 8
  • Ventilation 7
  • Features 7
  • Weight 7
  • Durability 9
Impact Protection System: MIPS | Weight: 406-grams (size Large)
Reasonably priced
Good sweat management
MIPS
Adjustable visor
Moderately heavy
Ventilation could be better

The Bell 4Forty MIPS is another affordable mountain bike helmet that outperformed many helmets that cost significantly more. It, like many higher-priced helmets, has a well-made and protective feel that offers ample coverage and a MIPS liner. It's also quite comfortable with a crowd-pleasing fit and an extensive adjustment range in its straps and Float fit system. It has a large adjustable visor that does a great job blocking the sun and is compatible with goggles. Testers also loved the unique sweat guide pad that managed to direct sweat out and away from the face and reduce dripping on your lenses.

While we liked almost everything about the 4Forty, we did have a couple of minor complaints. Despite having 15 vents, it provided adequate ventilation and was noticeably stuffier than the best ventilating helmets we have tested. It's also moderately heavy compared to the lighter weight competition, although we feel the weight is respectable considering the asking price. If you're on a budget, but you don't want to skimp on performance or features, we think the 4Forty MIPS is a great option to consider.

Read review: Bell 4Forty MIPS

Best Trail Riding Helmet


Fox Racing Speedframe Pro


87
OVERALL
SCORE
  • Protection 9
  • Comfort 9
  • Ventilation 9
  • Features 8
  • Weight 7
  • Durability 9
Impact Protection System: MIPS | Weight: 407-grams (size Large)
Comfortable harness
Highly adjustable
Dual-density EPS
Durable construction
Average weight
Fixed strap splitters

Despite its mid-range price tag, the Fox Speedframe Pro was one of our top-rated and most highly regarded helmets. This newer model nearly bested several helmets that cost significantly more. It packs many of the features we would expect from a top-of-the-line trail helmet, including a MIPS rotational impact system, dual-density EPS foam, a goggle-accommodating adjustable visor, and a highly adjustable harness system. Out on the trail, it was one of the most comfortable, well-ventilated models we tested. It feels light on your head and offers a secure, confidence-inspiring fit. Additionally, it received the "Best Available" 5-Star rating in Virginia Tech's independent helmet safety testing.

The Speedframe Pro is slightly heavier than the rest of the top-shelf models. It's not ridiculously heavy by any means, but it tacks on an extra fifty grams compared to the lightest models. Additionally, the Speedframe doesn't quite provide the same level of coverage as the other top contenders. Regardless, it's still well worth a look for anyone in the market for a choice new lid at an approachable price.

Read review: Fox Racing Speedframe Pro

Best for Protection


POC Kortal Race MIPS


89
OVERALL
SCORE
  • Protection 10
  • Comfort 8
  • Ventilation 9
  • Features 9
  • Weight 7
  • Durability 9
Impact Protection System: MIPS Integra | Weight: 401-grams (size M/L)
Class-leading head coverage
Great ventilation
Lots of protective features
Meets Dutch e-bike safety certification
New MIPS Integra rotational impact protection system
Expensive
May conflict with some sunglass arms

The Kortal Race MIPS is a new model from POC that stands out for its impressive protective qualities. The Kortal builds off the success of the ever-popular Tectal, with a deep fit and even more head coverage. It also features a new rotational impact protection system called MIPS Integra, which is strikingly similar to POC's SPIN system, although now it features a low-friction slip plane integrated into the foam of the helmet. This MIPS system is low profile and has the added benefit of not blocking any of the vents or air channels in this very well-ventilated helmet. In fact, this is one of the airiest helmets we've ever tested. The Kortal also features a new three-position adjustable visor that is designed to easily break away in the event of a direct impact. Additional features like Aramid bridges for structural integrity, a Recco reflector, and an NFC medical id chip further enhance its protective/safety qualities. The Kortal also carries all of the usual safety certifications in addition to the new Dutch e-bike standard.

Our gripes with the Kortal are few, but we did find a few nits to pick. We found the fit of the shell to be slightly narrower than most other helmets we tested, which may be an issue for those with particularly round head shapes. We think the new adjustable breakaway visor is great, although its position higher on the helmet limits its effectiveness at blocking low sun angles. The Kortal was designed to integrate with POC's new Devour sunglasses, but we found that the shell by the temples could conflict with the arms of many other sunglasses. It's also pretty pricey. That said, if you're looking for the most protective half-shell helmet on the market, we think the Kortal is worth every penny.

Read review: POC Kortal Race MIPS

Best for Extra Coverage


Giro Tyrant MIPS


80
OVERALL
SCORE
  • Protection 10
  • Comfort 9
  • Ventilation 6
  • Features 9
  • Weight 2
  • Durability 9
Impact Protection System: MIPS Spherical | Weight: 718-grams (size Large)
"Full cut" coverage
Dual-shell rotational impact protection
All-day comfort
Retro style
Adjustable harness
Heavy
Subpar ventilation

As part of a new wave of moto-inspired, open-face trail helmets, the Giro Tyrant provides significantly more head coverage than most of the standard mountain bike helmets we tested. Giro bills this beefy lid as a versatile option that can span the gap between gravity, trail, and dirt jump helmets. After weeks of rigorous testing, we support Giro's claim that it's an incredibly versatile helmet despite its heavy, protective construction. The first thing you'll notice when donning the Tyrant is that it shares a unique dual-shell construction with its half-shell counterpart, the Manifest. The inner shell is low-density EPP foam for minor impacts, and the outer shell is high-density EPS to absorb major collisions. Despite its double-shell composition, the helmet keeps a relatively low profile on your head, and the vents do a surprisingly good job of keeping things cool. Combine the innovative protection and coverage with Giro's Roc Loc harness system and refined shell shape, and you have a helmet that stays comfortable all day.

While we hugely appreciated the Tyrant's extra coverage and protection when things got rowdy, it does come with a weight penalty. This product is far heavier than your standard half-shell trail helmet. It doesn't make you feel like a bobblehead like some of the heavier full-face helmets out there, but you'll undoubtedly notice that it has more heft than your average lid. Given the Tyrant's intended purpose, we don't think the extra weight is a big problem. This model is perfect if you want to have fun on the trails and test your limits with the peace of mind provided by the protection from added coverage.

Read review: Giro Tyrant MIPS

Best for Ventilation


100% Altec


83
OVERALL
SCORE
  • Protection 8
  • Comfort 7
  • Ventilation 10
  • Features 8
  • Weight 8
  • Durability 9
Impact Protection System: Smartshock | Weight: 381-grams (size L/XL)
Great ventilation
Durable construction
Mid-range price
Not the most versatile fit
Average coverage

100% designed a remarkably calculated half-shell trail helmet with the Altec. For a brand that focuses mainly on full-face models, they nailed the Altec's ventilation and construction while managing to sneak in some clever features to make your life easier out on the trail. The first thing we noticed when donning this helmet for a ride was the breathability. Don't be fooled by its limited vents. They are large, strategically placed, and lead directly to an interior channel in the EPS foam shell that runs around the back of the head. It does a great job keeping your head cool and relatively sweat-free on hot days or long climbs. Beyond its airy feel, the Altec features a solid, durable construction that seems like it will last at least a few seasons if you can avoid head impacts. After two months of heavy testing, our test model looked as good as new. The finish on the polycarbonate outer shell doesn't scratch easily, and there's very little exposed EPS foam to chip away over time. Add in 100%'s Smartshock elastomer rotational impact protection, and the relatively low price compared to some of our other top models, and we think the Altec is a great value.

The two downsides we found associated with the Altec are the EPS shell fit and the average degree of head coverage. We noticed some minor pressure points at the back of the head every time we put the helmet on, but it never became a major discomfort out on the trail. It's not an uncomfortable feeling, but it lacks the glove-like fit suited for many head shapes. Moreover, it does provide a little bit of extra coverage compared to traditional cross country and road helmets; the Altec sits a bit higher on the head than some of the other top models in our test.

Read review: 100% Altec

Compare Products

select up to 5 products to compare
Score Product Price Our Take
90
$260
Editors' Choice Award
If you don't mind the price tag you'll be rewarded with top-of-the-line comfort, protection, and versatility
89
$200
One of the best helmets in this test, with good coverage, MIPS SL, excellent ventilation, and an impressively lightweight
89
$250
Top Pick Award
Fully-featured and high coverage, this is a protective new helmet from POC
87
$220
The combination of protection, comfort, ventilation, and lightweight make this one of our highest rated helmets
87
$170
Top Pick Award
This new model took us by surprise and was one of our top rated favorites
85
$225
Troy Lee Designs kept their classic looks but improved upon previous models with this fresh lid
83
$240
An updated version of Smith's popular Forefront helmet with the same comfortable fit and several improvements
83
$165
Top Pick Award
The Altec features a durable construction and ventilates as well as any model we tested
82
$220
This stylish, feature-laden helmet checks all the boxes but with a less versatile fit than our favorite models
82
$170
This model performs right alongside the best helmets in our test with just a little bit of added weight
80
$300
This fully-featured helmet comes equipped with Bontrager's WaveCel technology
80
$160
Top Pick Award
Loaded with innovations, this was our favorite full-coverage helmet
79
$160
A quality helmet option from Giro, though it was bested by the highest rated models in our review
78
$160
AC-level ventilation, generous coverage, and a forget-about-it fit are highlights of this helmet
78
$190
With a thick EPS shell and above-average weight, this heavy-duty trail has great coverage but a bulky fit
77
$169
Testers liked this helmet for its comfort, ventilation, and light weight
77
$100
Best Buy Award
This model is affordable and performs nearly as well as its more expensive competition
76
$110
Best Buy Award
This helmet is a competitive low-priced option
76
$200
Comfortable and protective with some unique design features, but it's heavy and has mediocre ventilation
75
$149
This helmet avoids frills and adeptly executes the basics
74
$200
Extra coverage and protection without breaking the bank
74
$75
Riders on a budget will find comfort and protection with this helmet
70
$210
A heavy and oversized trail helmet with an emphasis on safety and impact protection

Testing the new Troy Lee Designs A3 MIPS.
Testing the new Troy Lee Designs A3 MIPS.
Photo: Laura Casner

Why You Should Trust Us


Our mountain bike helmet review team consists of Jeremy Benson and Zach Wick. Jeremy is our Senior Mountain Bike Review Editor and a gravel and mountain bike racer who has been riding for three decades and has seen the progression of helmet technology over that time. He's also taken his fair share of diggers, suffering from more than one concussion and cracking a few helmets over the years. He knows from first-hand experience the importance of a quality helmet for both protection and comfort. Benson is a self-proclaimed heat of the day rider who appreciates the benefits of a well-ventilated helmet. Benson is also the author of Mountain Bike Tahoe, a mountain biking guidebook for the Lake Tahoe area published by Mountaineers Books.

Zach Wick has been riding and racing mountain, road, and cyclocross bikes for the last 15 years and has gone through his fair share of single-impact mountain bike helmets in that time. He knows what comprises a good helmet and won't hit the trails in anything he doesn't have confidence in. Zach has also spent years working in product development in the bike industry including five years in a test lab learning what makes a good product. He applies this experience and knowledge to our testing design to ensure our process is as rigorous as possible.

Click to enlarge
Click to enlarge
Click to enlarge

These two keep a close eye on new product releases throughout the year to stay up to date on the latest trends. For this review, they spent days researching countless models and discussing options before selecting 23 of the best to test and compare side by side. They tested each model through hundreds of miles of everyday riding on a variety of trails and in a wide range of weather conditions. Our review team evaluated the fit and comfort, features, ventilation, and adjustability of each helmet. They also swapped helmets out regularly for head-to-head comparisons and learned that some minute differences only become apparent through back-to-back testing.

Related: How We Tested Mountain Bike Helmets

The Giro Chronicle is a great option at a reasonable price.
The Giro Chronicle is a great option at a reasonable price.
Photo: Kelby Spore

Analysis and Test Results


In recent years the fit, style, comfort, and protection of helmets have all improved dramatically, and strapping on a helmet for a mountain bike ride has become as natural as buckling your seatbelt when you get in a car. It's a good thing because they are the single most important piece of protective gear you can wear. No two helmets are made equal, and the helmets in our test vary in their design approach. This review covers extended-coverage half-shell helmets designed for cross country, trail, and enduro riding along with a couple "full cut", open-faced helmets that offer even more coverage than your standard trail helmet. Our testers rated each model on protection, comfort, weight, ventilation, features, and durability. The combined scores led us to our best overall and top pick award winners.
Related: Buying Advice for Mountain Bike Helmets

Related: Best Bike Helmet of 2021


Value


The top-rated Giro Manifest Spherical, Specialized Ambush, and POC Kortal Race MIPS are three of the most expensive and also the highest performance models we tested. So you do get what you pay for, but sometimes you get quite a bit more. Of course, that isn't always the case. Some of the affordable models we looked at outperformed their more expensive counterparts. Riders looking for a good value from their helmet have plenty of options, including affordable models like the Giro Chronicle MIPS and the Bell 4Forty MIPS

The POC Kortal Race MIPS tops our charts for protection with loads...
The POC Kortal Race MIPS tops our charts for protection with loads of coverage, all the safety certifications, and lots of safety features.
Photo: Laura Casner

Protection


Since a helmet would be useless if it couldn't keep your head safe, protection is our most heavily-weighted metric. We aren't crash test dummies, nor are we a certifying agency, so our protection rating is based on a helmet's construction, head coverage, and rotational impact protection system. All of the helmets tested meet or exceed the US's CPSC Bicycle standard.


Head coverage plays a significant role in how protective a helmet is, and the amount of coverage varies from model to model. All of the helmets in this test are extended coverage half-shell helmets, though some offer a bit more coverage than others. The Giro Tyrant is one such helmet with a deep, "full cut" fit that drops down to provide more coverage on the temporal and occipital lobes. Lately, more and more "full cut" open face helmets have been cropping up. We also tested the Fox Dropframe, which offers similar coverage and styling. The Giro Manifest Spherical, Specialized Ambush, POC Kortal, Leatt MTB 4.0 AllMtn, and Giro Chronicle are the highest-coverage helmets we tested with a more traditional half-shell design.

More coverage = better protection. It's simple science, but it's...
More coverage = better protection. It's simple science, but it's still science.
Photo: Jeremy Benson

The construction of the helmet also contributes to its protection. Each model has an in-mold construction with a durable polycarbonate shell wrapped around an EPS foam liner. A number of newer helmets offer dual-density foam design with a mix of EPS and EPP foam intended to better manage impact forces from both high and low-speed impacts. The Giro Tyrant and Manifest Spherical feature an innovative dual-shell design in which EPP and EPS shells rotate against each other in the event of an impact. Other helmets, like the POC Tectal, POC Kortal, and the Specialized Ambush, also use aramid molded into their EPS foam to add strength.

You can see the two different types of foam in the Trey Lee A2. The...
You can see the two different types of foam in the Trey Lee A2. The denser EPS is dark grey, and the softer EPP is lighter grey.
Photo: Jeremy Benson

Rather than EPS foam, Smith uses a proprietary material known as Koroyd in their high-end helmets. Both the Session and the Forefront 2 employ this material in their construction. Koroyd looks like a honeycomb, or a bunch of straws packed very tightly together and is intended to crush or crumple in the event of an impact. Since this material is porous, Smith claims it provides excellent impact absorption with the added benefit of allowing air to pass through it. The Forefront 2 boasts nearly full Koroyd coverage inside the helmet, while the Session has two smaller strategically-placed panels on the sides of the helmet. Bontrager has created a similar cellular structure they call WaveCel used in the Blaze helmet. They claim this unique wave-shaped structure absorbs impact and also works as a slip-plane to reduce rotational impact forces.

Modern helmets are designed to absorb impact by allowing the helmet to partially self-destruct. The foam is to absorb impact, while the plastic shell protects the foam and distributes the force over a larger area. A crash typically results in crushing or cracking the helmet's foam and shell instead of your skull. Any of the helmets we tested is unsafe to continue riding after a significant impact and should be replaced.

A closeup view of the Koroyd in the Forefront 2. The structure looks...
A closeup view of the Koroyd in the Forefront 2. The structure looks reminiscent of a honeycomb and provides impact resistance and airflow at the same time.
Photo: Jeremy Benson, Heather Benson

Nearly every helmet in this review comes with a rotational impact protection system of some kind. Most use the industry-standard MIPS system, but a few companies have gone on to develop their own technologies. POC has developed SPIN, which is incorporated into the padding and is intended to absorb impact and reduce the forces of an oblique impact, while also reducing weight and not affecting the fit of the helmet. Leatt's Turbine 360 is meant to work similarly, with several Armourgel Turbines integrated into the construction of the helmet. 6D's ODS and 100%'s Smartshock are unique in their use of elastomer shock absorbers to reduce g-forces on impact. Bontrager's WaveCel is a new rendition and utilizes a porous structure that they claim can absorb impact and function like a slip-plane. MIPS created the MIPS SL system specifically for Specialized helmets, and it's built directly into the padding. POC now uses a new system called MIPS Integra in the Kortal.

The IXS Trigger AM and Fox Dropframe are the only helmets we tested without a rotational impact protection system. IXS chose to stick to the traditional EPS construction with no added frills for the version of the Trigger AM that we tested but has since started offering a MIPS version. Fox's Dropframe uses thick interior padding similar to traditional full-face helmet designs. While the science behind rotational impact protection isn't exactly settled, we think it's a logical system and are happy to have it when we're out riding.

MIPS SL technology is exclusive to Specialized helmets. It is...
MIPS SL technology is exclusive to Specialized helmets. It is integrated into the padding, which has rotational play in the thin black bands where the pads are connected to the helmet.
Photo: Jeremy Benson

MIPS, Spherical, Turbine, SPIN, ODS, Smartshock, LDL, WaveCel: Which safety standard is the best?


Rotational impact protection systems are now available in most helmets. MIPS (Multi-directional Impact Protection System) was the first on the scene and used to be the only game in town when it came to reducing rotational forces in a crash. Recently, several other technologies have entered the fray, Leatt developed Turbine, 100% designed Smartshock, Kali implemented LDL, POC created SPIN, Bontrager made WaveCel, and 6D designed ODS. Each of these systems aims to solve the same problem, but they approach it in a variety of different ways. Some systems, like Smartshock, LDL, SPIN, and 6D tout both direct and rotational impact protection, while traditional MIPS is designed strictly to help with rotational impacts.

Which technology is the best? The jury is still out. We recommend doing some research and deciding for yourself. The cost of these systems has come down in recent years, and nowadays, they only add about 5-10% to the price of a helmet. Since the whole point of a helmet is to protect the brain through a reduction of impact forces, we recommend paying the premium price for a helmet with one of these systems.

The Tri-Fix web splitter is well designed and adds to the Ambush's...
The Tri-Fix web splitter is well designed and adds to the Ambush's already impressive comfort.
Photo: Jeremy Benson

Comfort


Beyond safety, comfort is the next most important aspect of a helmet. A comfortable helmet feels natural and helps you stay focused on the trail. It's important to remember that comfort is subjective, and what works for you may vary based on the size and shape of your head. When in doubt, try on different models to find the size and fit that works best. Some brands' shell shapes tend to work better for specific head shapes while others are more versatile. Keep in mind that adjustable features like the retention system and chin straps play a role in how the helmet fits and our comfort rating.


All of the helmets tested use lightweight open-cell foam pads covered in moisture-wicking fabric to pad between the hard EPS foam and the rider's head. The thickness, quality, and placement of these pads play a significant role in a helmet's overall comfort. The most comfortable helmets have well-placed padding that covers the contact points between the polystyrene or MIPS liner and your head. Over-padded helmets can trap air and quickly overheat, so judicious pad placement is important.

The most comfortable helmets in our test were the Giro Manifest, Troy Lee A3, Fox Speedframe Pro, Giro Chronicle, Specialized Ambush, Giro Tyrant, and Smith Forefront 2. All of these helmets seemed to fit every tester like a glove. The Troy Lee A2 MIPS, Giro Montaro, and the Bell 4Forty MIPS also scored well by providing ample coverage while still offering an impressively comfortable fit. All of these helmets have an agreeable shape and feature padding covered with a wicking material.

A comfortable helmet can mean the difference between a grand...
A comfortable helmet can mean the difference between a grand adventure and a slog.
Photo: Zach Wick

Each helmet in our review employs a harness retention system. Commonly referred to as a fit or size adjustment, these enable riders to make micro-adjustments to dial in the fit of their lid. Retention systems typically come in the form of a two-sided plastic cradle at the back of the helmet with a dial in the middle that pulls tension evenly from both sides. This adjustment tightens or loosens to hug the head snugly for a secure fit. The size and shape of these adjustment dials vary considerably, as does their ease of use. Our favorite systems were those like Giro's Roc Loc that pulled tension around the entire head with small indexed positions rather than just pinching at the back.

Fit adjustment systems like this one on the Troy Lee A3 MIPS allow...
Fit adjustment systems like this one on the Troy Lee A3 MIPS allow you to get a precise fit with the turn of a dial.
Photo: Laura Casner

Another fit adjustment found on all the models in our test is the chin strap, including the strap splitter by the ears. Most chin straps offer a range of adjustability so that you can get the correct fit to secure the helmet on your head. More and more modern helmets use magnetic buckles that attach securely and can easily be opened and closed while wearing riding gloves. The strap splitter allows the user to adjust the position of the straps by the ears. Ideally, the straps shouldn't make contact with the ears. Our favorite strap systems are found on the POC Tectal Race SPIN, POC Kortal Race MIPS, Oakley DRT5, 100% Altec, and the Specialized Ambush, with a Y-shaped strap yoke that holds them in the perfect position. Some of the simpler splitters, like those on the Smith Convoy, struggle to keep the straps away from your ears and sitting flat on the side of your face, which can create a nuisance over time.

The Altec's massive vents facilitate some of the best airflow in our...
The Altec's massive vents facilitate some of the best airflow in our test.
Photo: Zach Wick

Ventilation


To rate each helmet's ventilation, we assess how well it works in real-world riding situations. We swapped helmets and rode with them back-to-back in the same conditions. Interestingly, our testers found that the number of vents doesn't directly correlate to how well a helmet's ventilation system works.


The size, shape, and placement of a helmet's vents are just as important as the quantity. The Giro Manifest was one of the best in the test, with long front-to-back vents and an excellent internal air channel design that keeps the air flowing through the helmet. Our other top-performing helmet for ventilation is the 100% Altec. Despite having only 15 vents, it keeps the air flowing and your head cool. A couple of the other best-ventilated helmets in our test are the Specialized Ambush and the POC Kortal Race MIPS.

The ANGi sensor is a unique feature that can be added to the...
The ANGi sensor is a unique feature that can be added to the Specialized Ambush helmet. This little unit can detect a crash and notify your emergency contact through the Specialized Ride App.
Photo: Jeremy Benson

Features


Features of mountain bike helmets are intended to improve fit, comfort, and protection while making your life a little bit easier out on the trail. One feature that all of the helmets we tested share is the visor—the main feature that sets mountain bike helmets apart from their road counterparts. Every model we tested has one, but they are certainly not created equal.


A visor's primary function is to shield your eyes from the sun, but they also serve as a little protection from rain and can help to deflect less consequential trailside obstacles. Helmet visors vary in size and shape, as well as in attachment method and adjustability. Many visors are adjustable and can be articulated up and down to improve visibility or to accommodate goggles. Others are static and fixed in the lowered position. Our gear testers prefer adjustable visors for their versatility and so that they can better accommodate goggles.

Our favorite visors are found on the Smith Forefront 2, the Giro Chronicle, Giro Montaro, and Bell 4Forty MIPS. They're all large enough to block the sun effectively, and each rotates up far enough to be entirely out of view and to accommodate goggles on the front. The POC Tectal also has an adjustable visor but is less user-friendly. It requires you to loosen a small screw to adjust and secure it in place. The Troy Lee A3 improves upon previous models with a 3-position Magnajust visor that can be pushed up high enough to accommodate goggles when not in use.

Click to enlarge
Click to enlarge

Many manufacturers are developing unique features as well. The Specialized Ambush, for example, can be used with the ANGi sensor (available as an aftermarket purchase) that attaches to the back of the helmet and can be synced to your smartphone and the Specialized Ride App. The app can track your ride, provide people with ride start and stop notifications, and even notify your emergency contacts in the event of a crash. These interesting new features incorporate technology into your helmet, and are likely to be seen more often in the near future. Likewise, POC has included a Recco reflector as well as an NFC medical id chip in the Kortal Race MIPS which can be read by first responders if you are unresponsive.

It's different, that's for sure. Testers had mixed feelings about...
It's different, that's for sure. Testers had mixed feelings about this system, but it is a unique approach to eyewear integration.
Photo: Jeremy Benson

Oakley has also gone out of its way to add features to the DRT5 to enhance eyewear integration. They use a Boa fit adjustment system that doesn't conflict with the arms of glasses, and they've incorporated a silicone sweat gutter that prevents drips on the lenses. On the back of the helmet, they've added an Eyewear Landing Zone in the form of two clips that hold the arms of your sunglasses relatively securely on the helmet. A quality visor flips up high for goggle compatibility, and with that Oakley has topped the charts with its features.

Click to enlarge
Click to enlarge

Weight


Our test helmets all fall into a fairly wide weight range from 12.35 to 25 ounces, or 350 to 718 grams. The Specialized Ambush was the lightest helmet in the review while the Giro Tyrant was the heaviest. Many of our top-performing helmets weigh within a few grams of each other. Differences in weight that small are hardly noticeable. For this reason, we put less emphasis on this metric than others.


In some cases, we found that the perceived weight of a helmet has as much to do with how well it fits as with the actual weight on the scale. The Troy Lee A3, for instance, was one helmet that felt considerably lighter than what the scale showed due to its excellent fit.

Durability


Our testers don't go out of their way to crash during testing. Therefore, the durability score is not correlated to crash resistance. It evaluates a helmet's ability to withstand daily use and common wear and tear. All of the helmets tested are designed to protect your head through partial destruction of the helmet during a crash. It is imperative that you replace your helmet after a significant impact. Beyond crash damage, most helmets should provide a responsible user with years of trouble-free use.


Helmets with full coverage outer shells that wrap entirely around the lower edge of the delicate EPS foam have better resistance to dings and dents from daily use and abuse. Most of the helmets in the test share this quality. We also observed how wear affected all the moving parts, fit adjustments, outer shells, and inner padding. The vast majority of the helmets that we tested are durably constructed and should span the test of time assuming that you can avoid hitting the deck.

With modern helmets, it's more comfortable than ever to keep your...
With modern helmets, it's more comfortable than ever to keep your head protected in the event of a crash.
Photo: Jeremy Benson

Conclusion


Mountain biking has the potential to be a high-impact activity, and protecting your head while you rip over rugged trails is the most important thing you can do. Choosing a helmet that will protect you from the inevitable crash but that is also durable enough to last, light enough to not weigh you down, and breathable enough to make you feel like you could ride for hours can be an overwhelming task. Our testers put each of these models through their paces to provide you with the best information possible before you make your next helmet purchase, and we hoped that this in-depth review helped to point you in the right direction.

Jeremy Benson, Zach Wick

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GearLab is founded on the principle of honest, objective, reviews. Our experts test thousands of products each year using thoughtful test plans that bring out key performance differences between competing products. And, to assure complete independence, we buy all the products we test ourselves. No cherry-picked units sent by manufacturers. No sponsored content. No ads. Just real, honest, side-by-side testing and comparison.

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