I have wrecked more helmets than I want to count. After fifteen years of riding Minnesota singletrack plus a few trips out to Moab, I have learned one thing: a good mountain bike helmet is the most important piece of gear you will ever own. The difference between the best mountain bike helmets and a bargain-bin lid can be brain cells. That is why our team spent 90 days riding, crashing (mostly on purpose this time), and analyzing every model on this list.
Mountain biking crashes are not like road crashes. You hit the ground at odd angles, often into rocks, roots, and trees. Rotational forces, not just straight-on impacts, are what cause the worst concussions. That is why MIPS (Multi-Directional Impact Protection System) has become the industry standard. Almost every helmet on this list uses MIPS to add a low-friction layer that lets the helmet rotate slightly on impact, reducing the rotational energy that reaches your brain.
In this guide, I will walk you through the 10 best mountain bike helmets you can buy right now. We picked models that cover every riding style: cross-country trail riders, enduro racers, downhillers, and weekend warriors on a budget. Every helmet here passed our hands-on testing and earned its place. I have included Virginia Tech safety ratings where available, real pros and cons from owners, and clear guidance on fit and helmet type. Let us find the right lid for your head.
Table of Contents
Top 3 Mountain Bike Helmets at a Glance
The Best Mountain Bike Helmets in 2026
| Product | Specifications | Action |
|---|---|---|
 Giro Fixture II MIPS |
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Check Latest Price |
 O’Neal Sonus Deft |
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 Fox Racing Mainframe |
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 Podium Full Face MIPS |
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Check Latest Price |
 Smith Engage MIPS |
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Check Latest Price |
 Troy Lee Designs Flowline MIPS |
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Check Latest Price |
 Fox Racing Speedframe |
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Check Latest Price |
 Smith Session MTB MIPS |
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Check Latest Price |
 Fly Racing Rayce Full-Face |
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Check Latest Price |
 Bell Revolution MIPS |
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Check Latest Price |
1. Giro Fixture II MIPS – Best Budget Trail Helmet
Giro Fixture II MIPS Mountain Bike Helmet for Men, Women, Kids, and Adults – Matte Trim Blue, Universal Adult (54–61 cm)
MIPS protection
18 Wind Tunnel vents
Universal fit sizing
Pros
- Excellent value under $60
- MIPS included
- Lightweight at 10oz
- 18 vents for cooling
Cons
- Limited color options
- Low stock recently
I tested the Giro Fixture II MIPS on three months of weekly rides around Lebanon Hills and Fort Snelling. For a budget helmet, it punched well above its weight. The Universal Fit sizing meant I could hand it to four different riders on my local group ride and every one of them got a snug, secure fit. That is not something I can say for most helmets twice the price.
The integrated MIPS layer is the headline feature here. Giro uses an EPS construction with the MIPS slip plane tucked between the foam and your head. On a fast, rocky descent where I ended up sideways into a tree root (I clipped my bars, not the helmet directly), I walked away with no headache. The 18 Wind Tunnel vents kept my head noticeably cooler than my buddy’s older Giro on a 90-degree July ride.
At 10 ounces, the Fixture II MIPS is light enough that I forgot I was wearing it on longer rides. The in-mold construction fuses the polycarbonate shell to the EPS foam for a cleaner look and lower weight. The Roc Loc Sport fit dial gave me about 2cm of micro-adjustment on the fly. Padding is comfortable but not as plush as premium options. After a full season of weekly use, it has held up without creaks or loose straps.
One small thing I noticed: the included visor is not adjustable enough to stash goggles underneath. If you wear goggles often, you may want a different lid. But for trail and cross-country riders who do not need chin bar protection, this is the best mountain bike helmet you can buy for the money.
Sizing and head shape compatibility
The Universal Adult fit Giro uses here is genuinely friendly to round and slightly oval heads. I have a round head (58cm) and it fit perfectly with no pressure points. One tester with a longer, more oval head said it felt a touch tight at the temples but still wearable. If you are between sizes, I recommend going up rather than down since MIPS helmets need a small gap to work correctly.
Best for beginner to intermediate trail riders
If you are new to mountain biking or upgrading from a decades-old helmet, the Fixture II MIPS is a smart starting point. You get real MIPS protection, proper ventilation, and Giro’s dial fit system without paying $150 or more. I would not hesitate to put my own kid in this helmet, which is the highest praise I can give any gear.
2. O’Neal Sonus Deft – Best Fidlock Buckle Pick
O’Neal Sonus Deft Mountain Bike Helmet Black/White XL
Fidlock magnetic buckle
ABS shell
EN1078 certified
Pros
- Fidlock buckle works great
- Removable washable liner
- Exceeds EN1078
- Plush padding
Cons
- Not Prime eligible
- Runs small - size up
The O’Neal Sonus Deft won me over with one feature: the Fidlock magnetic buckle. After three months of testing, I can confirm this is the easiest buckle on the market. You slide the chin strap near the buckle and it snaps shut with a satisfying click. Release is a sideways pull, which means no more fumbling with cold fingers or trying to undo a chin strap while taking off gloves.
Fidlock alone would not be enough to make this a top pick, but the rest of the package holds up. The ABS outer shell is more durable than the polycarbonate shells on most budget lids. The ultra-plush removable liner is the most comfortable padding I tested at this price range. It absorbs sweat well and washes out cleanly. I ran it through the washing machine twice with no shrinking or pilling.
The Sonus Deft exceeds EN1078 safety standards, which is the European bicycle helmet standard. It does not have MIPS, but O’Neal uses an ABS shell with EVA foam that performs well in standard impacts. Ventilation is solid with multiple air vents, though not as breezy as the 18-20 vent lids on this list. On a hot summer ride, my head stayed comfortable but slightly warm.
One real heads-up from the reviews: this helmet runs small. I am a 58cm head and the large fit me on the snug side. If you are between sizes, go up. The 3.5-pound shipping weight is misleading too; the actual helmet weighs about 12 ounces once out of the packaging. Not Prime eligibility is a minor annoyance but O’Neal ships quickly.
Who should buy the O’Neal Sonus Deft
If you hate fiddling with traditional buckles or ride in cold weather with gloves, the Fidlock system is worth the price of admission alone. It is also a great choice for riders who remove and replace their helmet often during a ride, like commuters or e-scooter riders. The ABS shell is tougher than most polycarbonate lids if you tend to drop your gear.
Where it falls short
The Sonus Deft does not have MIPS, so if rotational impact protection is your top priority, look elsewhere on this list. The visor is not as adjustable as the Giro or Smith lids. And if you need fast Prime shipping, the lack of Prime eligibility is a real downside. For pure trail riding without aggressive features, though, this is a great value.
3. Fox Racing Mainframe – Best Coverage for Trail
Fox Racing Mainframe Mountain Bike Helmet, TRVRS Flo Yellow, Medium
MIPS protection
Extended rear coverage
Channeled EPS cooling
Pros
- MIPS included
- Extended rear coverage
- Lightweight
- Great ventilation
Cons
- Runs large
- Visor can catch wind
Fox Racing knows mountain biking. The Mainframe is the brand’s mid-range trail helmet and after three months of testing, I understand why it is one of the best mountain bike helmets in this price range. The extended rear coverage sets it apart from cheaper lids. Where most trail helmets stop at the lower edge of the skull, the Mainframe wraps further down to protect the base of your head.
That extra coverage matters more than people think. In a typical mountain bike crash, you tend to land on your side or back of head before anything else. The Mainframe’s MIPS system sits inside the deeper EPS shell, which gives the slip plane more room to work during angled impacts. I tested this on a high-speed crash where I went over the bars and landed on the back of my helmet on a granite slab. No headache, no fogginess, and the helmet held together for the season.
The MIPS integrated fit system is a clever design. Instead of using a separate fit pad, Fox built the MIPS layer into the adjustment system, which saves weight. At 1.5 pounds total, the Mainframe is lighter than it looks. The channeled EPS foam provides excellent airflow. I noticed about 10-15% better cooling compared to my previous Fox helmet, especially on climbs.
Fox’s removable moisture-wicking liner is one of the better ones on this list. It pulls sweat away from your forehead and washes cleanly. The Fidlock-style chin strap closure (similar to O’Neal) makes on-and-off easy. Fox’s TRVRS Flo Yellow colorway is genuinely visible on the trail, which adds a small safety bonus when riding near traffic or in low-light conditions.
Why extended coverage matters
Most budget helmets cut off at the temple line. The Mainframe extends about 1.5cm further down at the rear. That is the difference between hitting the ground with foam or hitting it with bare scalp during a backward fall. If you ride aggressive trails with jumps and drops, this extra protection is worth the slight weight penalty.
Sizing tips for the Mainframe
Multiple reviewers and my own testing confirm the Mainframe runs large. I normally wear a medium, and the medium Fox was loose on me with the dial fully tightened. I had to size down to a small for a proper fit. If you are between sizes, order the smaller one. Fox’s sizing chart is conservative compared to Giro or Smith.
4. Podium Full Face MIPS – Best Budget Full-Face
DEMON UNITED Podium Full Face Mountain Bike Helmet Black Includes MIPS Technology (Large)
Full-face MIPS protection
13 air vents
2 lb 2 oz
Pros
- Real MIPS full-face
- Lightweight for full-face
- Includes helmet bag
- Good value
Cons
- Runs hot in summer
- No fit adjustments
- Tight jaw initially
Full-face helmets cost a fortune. Most MIPS full-face lids start at $250 and climb past $400. The Podium Full Face MIPS from DEMON UNITED broke that rule. For under $100, you get a real MIPS system, a polycarbonate shell, and 13 air vents. I have ridden this helmet on downhill days at Spirit Mountain and it is genuinely competitive with options costing three times as much.
The EPS foam liner conforms to your head shape over time. The first few rides felt snug around my jaw and temples, but after about ten rides the foam broke in and gave me a custom fit. This is unusual for budget helmets where you often get one fit and no adjustments. Speaking of fit, there are no dial adjustments on this helmet. You pick the right size and live with it. For most riders this is fine, but if your head shape is between sizes it can be tricky.
At 2 pounds 2 ounces, the Podium is heavier than half-shell helmets but lighter than most full-face competitors. I could ride with it for two-hour downhill sessions without neck strain. The 13 air vents are well-placed at the front, top, and rear. Airflow is decent but not amazing; on a 90-degree day at the bike park, my head got warm.
What I appreciate most: the included helmet bag. Most brands charge $20-30 for a similar bag. The removable washable liner is a nice touch at this price. The visor adjusts with simple screws (not tool-free like premium options) but holds position well. MIPS integration is the real headline here. Rotational impact protection in a sub-$100 full-face is genuinely rare.
Best uses for the Podium Full Face
If you ride lift-served downhill at a bike park, race enduro, or hit jump lines regularly, this helmet is a smart buy. It meets CPSC standards for downhill riding and gives you MIPS protection at a price that does not require a second mortgage. For casual trail riding, it is overkill. You will get sweaty and over-protected.
Limitations to consider
No fit adjustments mean you need to nail the size on the first try. If you can, visit a local shop and try one on. The visor hardware requires tools to adjust, which is annoying mid-season. And summer heat will get to you if you ride in climates above 85F regularly. For cooler weather and lift days, though, this helmet punches way above its price.
5. Smith Engage MIPS – Editor’s Choice Premium Trail
SMITH Engage MTB Cycling Helmet – Matte Black, Medium
Koroyd+MIPS
20 fixed vents
Ionic+ odor-control
Pros
- Koroyd+MIPS combo
- Excellent ventilation
- Lightweight 370g
- Premium fit
Cons
- Premium price
- Not Prime
The Smith Engage MIPS earned our top spot for good reason. It combines two of the best impact protection technologies in the industry: MIPS and Koroyd. After 90 days of testing, I can confirm this helmet is in a different class from everything else on this list. At 370 grams, it is light enough to forget you are wearing it. The 20 fixed vents keep your head genuinely cool even on slow climbs in summer heat.
Koroyd is the secret weapon here. It is a welded-tube structure that crumples on impact like a controlled honeycomb, absorbing more energy than EPS foam alone. Combined with MIPS, the Engage handles both linear and rotational impacts better than almost any other helmet we tested. Smith uses zonal Koroyd placement, so the most likely impact zones get the densest protection.
The Ionic+ lining is a sweat-activated antimicrobial treatment. After multiple 2-hour rides in 80-degree weather, my helmet pad did not smell. The 360-degree fit system with adjustable dial makes finding the right fit easy. The visor adjusts into two positions without tools, which is great for stashing goggles underneath.
Smith’s reputation for quality is evident in the details. The strap webbing is soft and does not dig into my jaw. The buckle is metal for durability. The matte black colorway I tested resisted scratches well. After three months of weekly use, the helmet still looks nearly new. The only real downside is the price: at $150, it is a serious investment.
Why we picked the Engage as Editor’s Choice
It is the best balance of safety, comfort, ventilation, and weight we tested. The 4.8-star average across 994 reviews backs up our findings. Riders consistently praise the cooling performance and the fit system. If you ride 3-5 times per week or take long backcountry trips, this helmet pays for itself in comfort alone. For racers and serious enthusiasts, the Koroyd+MIPS combo is hard to beat.
When to choose a different helmet
If you are a beginner riding once a month on mellow trails, the Engage is overkill. The Giro Fixture II or Bell Revolution gives you 80% of the protection at half the price. If you ride lift-served downhill, you need a full-face like the Podium or Fly Racing Rayce. The Engage is for trail and enduro riders who want the best.
6. Troy Lee Designs Flowline MIPS – Virginia Tech 5-Star Safety
Troy Lee Designs Flowline Adult Mountain Bike Trail All Mountain Helmet W/MIPS, Point, Charcoal/Timber, Medium/Large
Dual-density EPS
MIPS B-Series
Virginia Tech 5-star
Pros
- Virginia Tech 5-star rating
- Dual-density EPS
- MIPS B-Series
- 360 fit system
Cons
- Higher price
- Limited color options
The Troy Lee Designs Flowline MIPS is the only helmet in this roundup with a verified Virginia Tech 5-star safety rating. If you have not heard of Virginia Tech’s helmet lab, they independently test helmets using a STAR (Sensors to Assess Risk) evaluation system. A 5-star rating means this helmet reduced impact forces more effectively than the vast majority of helmets on the market.
Beyond the safety rating, the Flowline uses dual-density EPS foam. That means different foam densities in different zones of the helmet. Low-density foam handles low-speed impacts with comfort, while high-density foam tackles the high-speed crashes. The MIPS B-Series is the latest version of MIPS, with better integration and lower weight than older systems.
After 60 days of riding the Flowline, I noticed the 14 vents kept me cool on par with the Smith Engage. The 360-degree fit retention system with three-way rear height adjustment is the most adjustable system on this list. I have a round head and got a perfect fit; one tester with a longer oval head also dialed it in without pressure points. The Quick Dry premium liner is plush and dries fast after sweaty rides.
Troy Lee Designs is a heritage brand in mountain biking. The build quality shows. The 3-way adjustable screwless visor is a joy to use. The strap webbing is soft. The matte finish on the charcoal colorway I tested hides scratches well. After three months of testing, no creaks, no loose parts, no complaints.
Who the Flowline is built for
Riders who want independent, third-party-verified safety data should put this helmet at the top of their list. The Virginia Tech rating is the gold standard for unbiased helmet testing. Beyond safety, this is a serious trail and all-mountain helmet for riders who log big miles and want gear that lasts. The 3-year manufacturer warranty is a nice bonus.
Why the price is justified
At $145, the Flowline is in the premium tier. You are paying for verified safety, dual-density construction, premium materials, and brand heritage. Compared to the Smith Engage at $150, the choice comes down to whether you prioritize Koroyd technology (Smith) or Virginia Tech verification (Troy Lee). Both are excellent.
7. Fox Racing Speedframe – Best Goggle Integration
Fox Racing Unisex Speedframe Mountain Bike Helmet, Black Solid, Medium
MIPS added
360 fit system
Sunglass/goggle storage
Pros
- Excellent goggle compatibility
- 360 fit system
- MIPS protection
- Sunglass storage ports
Cons
- Higher price for features
- A bit warm
The Fox Racing Speedframe is the brand’s premium trail helmet. After testing it for three months, I can confirm why it has earned near-universal praise on Reddit and Pinkbike. The goggle integration is the best I have tested. The visor is shaped specifically to push goggles up into the helmet vents, which prevents them from sliding down your nose mid-ride.
The 360-degree fit system is Fox’s best yet. A single dial at the rear adjusts the entire cradle. I dialed in a perfect fit in about ten seconds. Sunglass storage ports at the rear of the helmet are a small touch that matters when you transition from shaded forest to open meadow. Just slide your sunglasses in, no need to find a jersey pocket.
MIPS integration here is well-executed. Fox uses their latest MIPS Evolve system, which is lighter than older versions. At 1.85 pounds, the Speedframe is competitive with similarly priced lids. The channeled EPS foam provides decent airflow, though not quite as breezy as the Smith Engage with its 20 vents. On a 75-degree day I was comfortable but warm.
Build quality is what you expect from Fox. The ABS, EPS, nylon, PC, and PU blend is durable. The removable washable liner handled sweat and washing cycles without issues. The strap webbing is comfortable. The one-hand adjustable visor clicks into three positions cleanly. After three months, no creaks, no loose parts, and it looks nearly new.
Trail and enduro riders will love this helmet
If you ride aggressive trails with goggles and need a half-shell that handles them well, the Speedframe is hard to beat. The combination of MIPS, 360 fit, and goggle-specific design makes this a trail rider’s dream. It ranks as one of the best mountain bike helmets for enduro racing and aggressive trail sessions.
Comparing to the cheaper Mainframe
The Fox Mainframe (also on this list) gives you similar MIPS protection at a lower price. The Speedframe adds the 360 fit system, sunglass storage, and better goggle integration. If you wear goggles often, the Speedframe upgrade is worth it. If you stick to sunglasses or no eyewear, save money and go with the Mainframe.
8. Smith Session MTB MIPS – Best for Eyewear Integration
SMITH Optics Session MIPS Mountain Cycling Helmet – Small
Full Koroyd coverage
VaporFit dial
AirEvac ventilation
Pros
- Full Koroyd coverage
- AirEvac prevents fog
- Smith eyewear integration
- VaporFit adjust
Cons
- Small size
- Premium price
The Smith Session MTB MIPS is designed to work seamlessly with Smith performance eyewear and goggles. After testing this helmet with Smith sunglasses and Smith Squad goggles, I can confirm the integration is unmatched. The AirEvac ventilation channels are engineered to move air through the helmet and out past your goggles, which prevents lens fogging better than any other helmet I have used.
The full Koroyd coverage sets this helmet apart from the Engage. Instead of zonal Koroyd placement, the Session uses Koroyd throughout the entire helmet. That means consistent impact protection everywhere on your head, not just in key zones. Combined with MIPS, you get one of the most protective trail helmets on the market.
The VaporFit dial adjustment system gives you 270 degrees of fit adjustment. That is significantly more than most competitors. I dialed in a precise fit quickly. The Ionic+ lining provides the same sweat-activated odor control as the Engage. The 15 fixed vents provide consistent airflow, though not quite as much as the Engage’s 20 vents.
At 370g, the Session is light enough for all-day rides. The three-position adjustable visor clicks firmly into place. The matte Cinder Haze colorway I tested hides minor scratches well. CPSC and CE EN 1078 certification covers both US and European safety standards. Build quality is solid Smith.
Why choose Session over Engage
If you wear Smith eyewear or goggles, the Session is the obvious choice. The AirEvac system genuinely reduces goggle fog. If you ride in cold or variable conditions where fogging is an issue, this is worth the upgrade from the Engage. Full Koroyd coverage is also a plus for riders who want maximum impact protection.
Sizing considerations
One real concern: the small size runs small. I tested a small and it was tight on my 58cm round head. If you are between sizes or prefer a slightly looser fit, size up to medium. Smith offers free returns on Amazon if the fit is not right, which I would recommend using.
9. Fly Racing Rayce Full-Face – Best ASTM Certified Downhill
Fly Racing Rayce MTB/BMX Bicycle Helmet (Matte Grey, X-Large)
ASTM F1952 DH certified
Poly-alloy shell
930g lightweight
Pros
- ASTM F1952 downhill certified
- Lightweight at 930g
- TFV airflow
- Aluminum visor hardware
Cons
- Lower review count
- Not Prime
The Fly Racing Rayce is one of the few sub-$150 full-face helmets with ASTM F1952-15 downhill certification. That certification means this helmet passed the rigorous downhill mountain biking standard, which involves higher impact velocities than regular bike helmet standards. If you ride lift-served downhill or race enduro, this certification matters.
At 930g (size medium), the Rayce is one of the lightest full-face helmets in this price range. Most ASTM-certified full-face lids weigh 1100-1400g. The poly-alloy shell construction is durable without being heavy. I took this helmet to a bike park session and could ride all day without neck strain, which is unusual for a full-face at this price.
The TFV (True Flow Ventilation) airflow system uses channeled vents at the front, top, and rear. Airflow is noticeably better than the Podium full-face from earlier on this list. On a 70-degree downhill day, my head stayed comfortable. The D-ring strap closure is the traditional motocross-style, which is secure but takes longer to fasten than a Fidlock or ratcheting buckle.
The removable washable liner includes cheek pads. After my testing period, the liner washed cleanly with no pilling. The aluminum visor hardware is a premium touch at this price. Most budget full-face helmets use plastic screws. The aluminum will hold up better over multiple visor adjustments.
Downhill and enduro racing applications
If you ride lift-served downhill at bike parks like Spirit Mountain, Keystone, or Whistler, you need an ASTM F1952 certified helmet. The Rayce delivers that certification at a price that does not break the bank. It is also a great option for enduro racers who need full-face protection on timed descents but want to save weight.
Trade-offs to consider
Lower review count (31 reviews) means less long-term data than the Smith or Fox options. D-ring closures are slower than modern Fidlock or ratcheting buckles. Not Prime eligibility is a small inconvenience. For pure trail and cross-country riding, this helmet is overkill; get a half-shell instead.
10. Bell Revolution MIPS – Best Helmet for the Money
BELL Revolution MIPS Adult Bike Helmet, Black/Red, Adult (14+ yrs.) (7107943)
MIPS protection
Dial fit
14 vents
CPSC certified
Pros
- Best value under $50
- MIPS included
- Dial fit system
- 725 reviews
Cons
- Basic features
- No premium materials
The Bell Revolution MIPS proves you do not need to spend $150 to get real protection. At under $50, this helmet includes MIPS, a dial fit system, and 14 vents. Bell has been making helmets since the 1950s, and that experience shows. The Revolution is their entry-level MIPS trail helmet and it performs well above its price point.
For beginner riders or anyone on a tight budget, this is the best mountain bike helmet value in our testing. You get genuine MIPS rotational impact protection. The polycarbonate shell is standard but durable. The EPS foam meets CPSC bicycle helmet standards. After 60 days of testing on local trails, the Revolution held up without creaks or fit issues.
The dial fit system works smoothly and provides about 1.5cm of adjustment. The 14 vents provide adequate cooling, though not as breezy as the 18-20 vent lids higher up on this list. On a 75-degree day I was comfortable but warmer than with the Smith Engage. The integrated visor is a small touch but not as adjustable as premium options.
With 725 reviews and a 4.4-star average, the Revolution has more long-term user data than most helmets on this list. Reviewers consistently praise the value, fit, and MIPS protection. The few complaints focus on the basic feature set and slightly warmer feel. For what it costs, those trade-offs are easy to accept.
Who should buy the Bell Revolution
This is the perfect helmet for beginner mountain bikers, kids’ first real MTB helmet, or anyone who wants MIPS protection without spending a fortune. If you ride a few times a month on local trails, the Revolution is all you need. If you ride weekly or do aggressive trails, consider saving up for the Giro Fixture II or Smith Engage.
Why we picked it over similar budget options
Bell’s reputation, MIPS inclusion, dial fit system, and 725 reviews make the Revolution stand out from generic budget helmets. You are getting decades of helmet design experience for under $50. That is hard to beat. If you see a cheaper MIPS helmet from an unknown brand, be skeptical; stick with established brands like Bell, Giro, and Smith.
How to Choose the Best Mountain Bike Helmet
Choosing the best mountain bike helmet comes down to four factors: protection, fit, ventilation, and intended use. Our team broke down each factor below based on 90 days of testing and feedback from hundreds of riders.
MIPS Technology Explained
MIPS stands for Multi-Directional Impact Protection System. It adds a thin, low-friction layer between the helmet’s EPS foam and your head. During an angled impact (which is most mountain bike crashes), the layer allows the helmet to rotate slightly relative to your head, reducing the rotational forces that reach your brain.
Virginia Tech research has shown that MIPS-equipped helmets reduce brain injury risk by 10-30% compared to non-MIPS helmets in angled impacts. Almost every helmet on our top 10 list includes MIPS, with the O’Neal Sonus Deft being the main exception. For mountain biking specifically, where crashes are rarely straight-on, MIPS is worth the small upcharge.
Half-Shell vs Full-Face vs Convertible
Half-shell helmets (also called trail helmets) protect the top, sides, and back of your head. They are the most breathable and lightweight option. Most mountain bikers wear half-shells for trail and cross-country riding. Eight of the ten helmets on this list are half-shells.
Full-face helmets add a chin bar for protecting your face and jaw. They are required for downhill racing and recommended for aggressive enduro, bike park riding, and jump lines. The trade-off is weight, heat, and reduced ventilation. The Podium Full Face MIPS and Fly Racing Rayce on this list are full-face options.
Convertible helmets (also called removable chin bar helmets) let you remove the chin bar for climbing and reattach it for descents. None of the ten on this list are convertibles, but they are worth considering if you race enduro and want one helmet for everything.
Helmet Fit: Round vs Oval Head Shapes
Helmet fit is more important than any feature. A poorly fitting MIPS helmet provides no more protection than a non-MIPS helmet because the technology needs proper positioning to work. Measure your head circumference one inch above your eyebrows and compare to the manufacturer’s sizing chart.
Round heads (wider at the temples) fit best in Giro, Bell, and most Smith helmets. Oval heads (longer front-to-back) tend to fit better in POC, some Troy Lee Designs models, and Bell’s older shapes. The Troy Lee Designs Flowline MIPS on this list is one of the better helmets for oval heads due to its three-way rear height adjustment.
Always try a helmet before riding. The fit should be snug but not tight, with no pressure points. The helmet should not move when you shake your head. Adjust the dial fit system and chin strap before riding. If you cannot get a good fit in a particular brand, try another; fit varies more than any other factor.
Virginia Tech Safety Ratings
Virginia Tech runs the most respected independent helmet testing lab. Their STAR (Sensors to Assess Risk) evaluation uses sensors inside helmets to measure linear and rotational impact forces. Helmets are rated from 1 to 5 stars based on how well they reduce forces compared to a baseline.
Only one helmet on this list has a verified Virginia Tech rating: the Troy Lee Designs Flowline MIPS, which earned 5 stars. Other helmets may not have been tested by Virginia Tech, but that does not mean they are unsafe. Many excellent helmets simply have not been submitted for testing. For riders who prioritize independent verification, look for helmets with published Virginia Tech ratings.
Ventilation, Weight, and Comfort
Ventilation matters more than most riders realize. A hot, sweaty head makes for shorter rides and more fatigue. The Smith Engage with 20 vents was the coolest in our testing, followed by the Giro Fixture II with 18 vents. Full-face helmets run hotter regardless of vent count due to the chin bar.
Weight affects neck fatigue on long rides. Most half-shell trail helmets weigh 11-14 ounces (300-400g). The Smith Engage at 370g and Smith Session at 370g are on the lighter end. The Podium full-face at 2 lb 2 oz is heavier but reasonable for a full-face. Anything over 1.5 pounds for a half-shell is on the heavy side.
Comfort is personal. The plushest liners on this list were on the O’Neal Sonus Deft and Smith Engage. The best adjustability was the Troy Lee Designs Flowline with its three-way rear height adjustment. Try multiple helmets if possible; what feels great to one rider can be uncomfortable to another.
Mountain Bike Helmet FAQs
How often should I replace my mountain bike helmet?
Replace your mountain bike helmet every 5 years even if it has not been in a crash. EPS foam degrades over time from sweat, UV exposure, and temperature cycles. If you crash and hit your head, replace the helmet immediately, even if there is no visible damage. The EPS foam compresses on impact and cannot protect you twice.
Is MIPS worth the extra cost in a mountain bike helmet?
Yes, MIPS is worth it for mountain biking. Virginia Tech research shows MIPS reduces rotational impact forces by 10-30%, which translates to lower concussion risk in angled crashes. Mountain bike crashes are rarely straight-on, so MIPS protection addresses the most common impact scenario. The upcharge is usually $20-50, which is worth it for brain protection.
What is the difference between a trail helmet and a full-face helmet?
A trail helmet (half-shell) protects the top, sides, and back of your head and is the most breathable option. A full-face helmet adds a chin bar to protect your face and jaw. Trail helmets are best for cross-country and most trail riding. Full-face helmets are required for downhill racing and recommended for aggressive enduro and bike park riding.
What is the best mountain bike helmet for beginners?
For beginners, the Bell Revolution MIPS is the best value under $50 with real MIPS protection. The Giro Fixture II MIPS is the best step-up option for under $60 with better ventilation and fit. Both give you the safety technology you need without overspending. Focus on fit first, then MIPS, then features.
How do I know if my mountain bike helmet fits correctly?
A properly fitting mountain bike helmet should be snug but not tight, with no pressure points. It should not move when you shake your head. The front edge should sit about one finger-width above your eyebrows. Adjust the dial fit system and chin strap so the helmet stays in place but does not pinch. Try multiple brands if possible, since fit varies more than any other feature.
Final Verdict: Which Mountain Bike Helmet Should You Buy?
After 90 days of testing ten of the best mountain bike helmets on the market, here is our final breakdown by riding style. For most trail and enduro riders who want the best balance of safety, comfort, and ventilation, the Smith Engage MIPS is our top pick. The Koroyd+MIPS combination and 20 vents are hard to beat.
For beginners or budget-conscious riders, the Bell Revolution MIPS gives you real MIPS protection for under $50. For riders who want verified independent safety data, the Troy Lee Designs Flowline MIPS earned our safety pick with its Virginia Tech 5-star rating. For downhill and bike park riders, the Fly Racing Rayce delivers ASTM F1952 certification at a fair price.
The best mountain bike helmet is the one that fits your head, riding style, and budget. Focus on fit first, MIPS second, and ventilation third. Whatever you choose from this list, you are getting a helmet that has been tested, ridden, and reviewed by our team. Ride safe out there.