One essential piece of kit for all mountain bikers is a good helmet. The best mountain bike helmets combine a high level of protection with features such as visors, ventilation and padding, and should rate highly for comfort and style too. We’ve extensively tested and reviewed MTB helmets on the market, and this is the very best of the best.

This guide is for regular open-face helmets, suitable for most trail and cross-country riding. If you’re looking for full-face or convertible lid for bike park riding or gravity use, then check our our guide to the best mountain bike full face helmets.

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Bell Sixer MIPS

A great helmet at a great price

Weight: 392g | Colours: White, grey, green, blue, Fasthouse | Sizes: S, M, L | Rating: 10/10

Pros: Great alternative if you’re not a fan of the Bell Super’s aesthetic Cons: Very very slightly fiddly vertical retention adjustment

Always at the forefront of helmet tech, Bell’s Sixer brims full of tech and provides a superlatively comfortable fit. Varying densities of foam are used to build up the structure of the Sixer, each one optimised to absorb different impact velocities.

The visor tilts up in stages sufficiently to stash goggles beneath, and there’s a rubber strap grip at the back. We love the Float Fix Race retention device, which is highly adjustable with no pinch points, and your riding buddies will love the X-Static pads that help prevent funky smells building up on hot days.

A great looking helmet at a great price. In terms of features and detail, the Sixer is step up from the Super 3. It’s comfortable and looks sleeker. A great helmet, at a great price, test winner in the all-rounder trail riding category.

Read our full test review of Bell Sixer MIPS

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Fox Dropframe MIPS

Best mountain bike helmet for extra protection and coverage

Weight: 391g | Sizes: S, M, L, XL | Rating: 10

Pros: Great coverage, plenty of ventilation, lightweight, MIPS liner

Cons: Visor isn’t adjustable

The Fox Dropframe is a half-way house between a full face and half shell. It doesn’t have a chin bar but there’s increased coverage at the side of the jaw, over the ear and back of the neck. It’s a distinctive design but it’s also incredibly lightweight for a helmet with this level of protection. 

Its stable – it literally doesn’t move even on the roughest descents – and also incredibly comfortable and, unlike the Giro Switchblade, is dead easy to put on because you can pull those side extensions slightly apart, so you don’t catch your ears. 

With 15 vents, the DropFrame ventilation is really good for a bigger helmet. The neck can get a bit sweaty but this helmet is definitely our choice for winter rides. If we have one gripe it’s the lack of an adjustable visor. 

Some helmets fit like a glove and are nice to wear – this is one of them. It’s also super lightweight, provides unrestricted visibility but with significant increase in protection over a regular open face.

Read our full review of the Fox Dropframe MIPS helmet

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Bell Super Air Spherical

Best on test: best mountain bike helmet for all-round protection and comfort

Weight: 484g | Sizes: S, M, L | Rating: 10

Pros: Great ventilation, absorbent padding, fully adjustable visor, comfortable, plenty of protection, optional chin bar

Cons: Old-school snap clasp

Bell’s new Super Air is the first trail helmet with Flex Spherical + MIPS technology. Crucially, it will move 10-15mm during an impact event but it doesn’t impact on the sizing or the fit – in fact the Bell Super Air is easily the most comfortable half shell on test. Bell’s retention device is also attached to the MIPS, so there’s no restriction of movement.

With 18 vents and four brow ports, air flow is excellent and if you do sweat there’s plenty of padding to soak it up, especially around the forehead. 

Like the Montaro II, the visor is fully adjustable and there’s plenty of room for stashing goggles. Unfortunately there’s no Fidlock SNAP buckle but the old-school clasp gets the job done.

For trail use the Super Air Spherical is comfortable, fits like a glove and offers a ton of protection via the dual-density closed cell foam construction. The best thing about this helmet is you can attach an optional chin bar to the front, which is available for an additional £89.99, which means this helmet also works as one of the best convertible helmets. 

The attention to detail, the raft of protective elements, superb fit and comfort and this is easily the best helmet on test.

Read our full review of the Bell Super Air Spherical helmet

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Bell Super 3 MIPS

Does everything as top-end helmets whilst costing less

Weight: 426g | Sizes: S, M, L | Rating: 10/10

Pros: Even more of a bargain Cons: Can run on the warm side

The best just got cheaper. Yes, Bell’s convertible Super 3 enjoyed a £20 price drop in recent years, making it even more of a bargain.

It’s still a great fit thanks to the Float Fit retention system and it offers a decent amount of ventilation considering the amount of protection on offer. There’s a wide peak that swings up far enough to let you stash a set of goggles underneath and the whole construction feels solid and durable.

Its real party trick, however, is the optional chinbar, available for an extra £80. Invest in that and you’ve got two helmets in one, making it the perfect companion for a day in the bike park.

The Bell Super 3 is the best trail helmet because it strikes the right balance between durability and venting. It’s weighty and the lower edge where the EPS is left exposed is starting to look tatty but its cracking value for money and the chin bar compatibility lifts it to a whole different level.

Read our full test review of the Bell Super 3 helmet

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Giro Tyrant

Extra peace of mind without cooking your brain

Weight: 623g | Colours: Yellow, blue, black | Sizes: S, M, L | Rating: 10/10

Pros: Great for when full-face is too hot Cons: There’s a weight penalty

This quirky looking lid is being worn by 50:01’s very own Ratboy AKA Josh Bryceland in the marketing shots. So does that mean it’s irrelevant for the rest of us? Riders who prefer to ride a loop on a Sunday instead of finding twenty different ways to slide along a log? Not in our opinion.

Resembling a motorcycle trials helmet, the new Giro Tyrant adds a bit more protection to the enduro half-shell, placing it somewhere between an open face and a full face.

The outer hardshell is really durable, while inside there’s MIPS’ new Spherical liner, where the whole inner section of foam can rotate in the event of an angular impact. Dual density foam further helps with impact absorption, but even with all that extra coverage, there’s enough airflow to keep you comfortable on a summer’s day.

Read our full test review of the Giro Tyrant helmet

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Oakley DRT5

One of the most comfortable helmets we’ve experienced

Weight: 440g | Colours: White, blue/black, grey, green | Rating: 10/10

Pros: Excellent for hot heads Cons: More expensive than Bell Super 3

One of the most famous brands in sunglasses has branched out into the helmet market with the Greg Minnaar signature DRT5, and for a first attempt, it’s seriously impressive.

The BOA retention system, in combination with the MIPS liner, is luxuriously comfortable, while a silicone sweat gutter up front keeps drips out of your eyes. There’s also a clever set of clamps at the back of the helmet that’ll securely hold your sunglasses when you don’t need them, even if they don’t have a squashed O on the arms.

At 440g the Drt5 is on the heavy side, but comparable with favourites like the Bell Super 3, and its secure hold on your head means it’s not really noticeable when riding. It’s also slightly more money than top end lids like the Giro Montaro or Endura MT500.

But it’s a step up in quality from both of those, the finish is brilliant, and the extra features that could be so gimmicky are actually astute and desirable.

Read our full test review of the Oakley DRT5 helmet

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Fox Speedframe Pro

Well thought out, comfortable and protective

Weight: 437g | Sizes: S, M, L | Rating: 10/10

Pro: Form, function and a fair price Con: Liner moves around a little

A new kid on the block, but it has MIPS and a dual-density EPS, it also fits great and feels comfortable. It also looks way better than any previous Fox helmet we’ve tested, and while that shouldn’t matter, somehow it does.

Offers a a ton of protection and have all the goggle-parking, camera-wearing, visor-tilting features you’ll ever need. Launched relatively recently, the Speedframe Pro went straight to the top of our helmet rankings when we tested it.

Dual density foam is employed throughout, ensuring the Speedframe is as effective as possible in both high and low speed impacts, while the MIPS liner further helps dissipate rotational forces.

Fox has ensured ample venting too, and the visor tilts right up if you want to stash goggles underneath. Finally, clever features such as the quick-lock magnetic strap closure help elevate the Speedframe Pro above its rivals.

Read our full test review of Fox Speedframe Pro helmet

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Giro Women’s Source MIPS

Best budget mountain bike helmet

Weight: 347g | Sizes: S, M | Rating: 9

Pros: MIPS, sweat-absorbing patting, indexed adjustment on the visor, good coverage

Cons: Chin strap buckle is small and flimsy

The Source features Giro’s Roc Loc 5 retention device, MIPS liner, Coolfit Ionic+ padding. The visor has indexed adjustment that allows me to park my goggles under it. The shell extends down over the temples and at the back, and I appreciate the extra coverage.

It fits really well, it’s comfortable, and I can adjust the retention device easily while riding. The venting is good, and when I wear goggles the strap sits securely on the back. The MIPS doesn’t impact on the sizing, and moves easily. 

My only criticism is that the buckle on the chin strap is a bit small and flimsy compared to Giro’s high-end Montaro II lid, so I find it hard to release. 

While this version of the helmet is labelled women’s, it’s no different to the Giro Source MIPS: the only difference here is a selection of colours only available in the women’s range, and a smaller size range offering. Apart from that, there is no reason whatsoever that women have to go for this helmet specifically over the others. 

That said, the Giro Source is a comfortable, well-vented and good-looking trail helmet that I’d recommend to any rider.

Review by Alice Burwell.

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Specialized Camber

Great budget helmet that’s excellent value for money

Weight: 392g | Sizes: S, M, L | Rating: 9

Pros: Great value for money, good ventilation, secure on-board glasses storage, lightweight, comfortable

Cons: Minimal padding with no antibacterial treatment, less secure on rough terrain, fixed visor

Visually the Camber looks like the more expensive Ambush 2 but to keep the cost down it runs a single EPS layer rather than the better helmet’s dual-density construction. To add protection there is a MIPS SL liner but again due to budget constraints this is slightly thicker than the one elsewhere, although it does move more easily than the Ambush 2’s version. 

The padding is pretty minimalist, and there’s no antibacterial treatment to it, but Specialized helmet engineers have built in 4D brow cooling, which is just a fancy way of saying they left a ventilation gap between the shell and the brow pad.

The Camber features an Integrated Fit system adjusted via a ratchet at the back. It takes up slack quickly but the indents on the dial are too big, so it’s easy to fall between two stools. It also sits too high, so doesn’t cup the occipital bone (that’s the lump at the back of your head) very well and of all the open face helmets here, the Chamber felt the least secure when riding rough terrain.

Specialized has opted for a fixed visor, it says not to cut costs but because a moveable peak can block the front vents and cut down on ventilation. The Camber is well vented but it’s not anything special. Specialized does add two rubber pads underneath the visor, creating a storage solution for your eyewear – you simply poke the arms of your riding glasses into this space they’re going to be held fast. Despite the claims there’s not really enough space for goggles but the visor does look incredibly sleek.

We can’t fault the comfort of the Camber, and Specialized really nails the details. We really like the Tri-Fix splitters that keep the straps clear of your ears and although it’s not that stable, it’s lightweight and cracking value for money.

Read our full review of the Specialized Camber helmet

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Giro Montaro II MIPS 

Best helmet for hot conditions

Weight: 421g | Sizes: S, M, L, XL | Rating: 9

Pros: Roc Loc Air 5 MIPS protection, secure and comfortable fit, antimicrobial padding, adjustable goggle, detachable POV camera mount, excellent ventilation

Cons: Old-style clasp, visor fixing screws can work loose, rear coverage less than competitors

The Montaro II uses the same in-moulded construction as the original version, where the EPS and Roll Cage reinforcement is placed in the mould with the microshell and then bonded. The new version gets a new Roc Loc 5 Air MIPS – Giro combines the movable liner and retention device into a single part, which eliminates bulk and weight. 

Interestingly it also changes the sizing slightly – the large Montaro we tested last time felt a little snug and perched, this one doesn’t. It also feels more secure even without the straps fastened and is generally more comfortable too. The retention device itself is easily the most accurate and is only indexed one way, so you can release tension quickly. So far, the anti-microbial Ionic+ padding hasn’t retained any odour but then there’s not a lot of it. The reason for that is Giro has really dialled the venting on the Montaro II – with 16 vents and sculpted internal channelling it’s the best on test.

The visor is adjustable and indexed, so it holds its position, and is stiff enough to be adjustable with one hand. There’s plenty of space underneath for a full goggle, and you also get a matching strap gutter. To accommodate a POV camera, Giro borrows the mount from its sister company Bell. This clips into the rear vent and even has a breakaway feature, so you’ll snap the cheap bit not your £500 camera.

There is a lot of good stuff about this helmet – the venting is excellent; the fit is superb and it’s also excellent quality. However, the devil is in the detail and the reason it plays second fiddle to the Bell Super Air Spherical is the old school clasp, the fixing screws on the visor can work loose, and coverage doesn’t extend quite as far down at the back.

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Troy Lee Designs A3

Comfort and style rolled into one

Weight: 411g | Sizes: XS/S, M/L, XL/XXL | Rating: 9/10

Pros: Stunning looks and superb comfort Cons: You’ll need deep pockets

To boost impact protection, the Troy Lee Designs A3 uses a dual-density EPS core with in-moulded mixes of EPP (expanded polypropylene) and EPS (expanded polystyrene), all wrapped up into a polycarbonate shell. To help deal with rotational impacts, the A3 gets a B-series MIPS liner integrated into the shell. This doesn’t move as smoothly as the one in the Bell Super Air Spherical helmet but it’s on par with Giro Montaro II. 

Comfort and fit are excellent but that’s because the A3 is one of most heavily padded helmets on test. This cuts down on the ventilation but it’s nowhere near as sweaty as the old A1.

Troy Lee Designs has also updated the visor of the A3, which now features Magnajust. Basically, the visor has a tab that locates into three recesses on the front of the helmet but to stop it slipping out there’s a little magnet, hence the name. It feels crude but it works pretty well and you can also flip the visor right back if you want to park your goggles underneath.

The 360° retention device totally encircles your head and is height adjustable via some simple press studs. It also features a silicone brow pad (different sizes are included) and while this is effective, we found it can stick to your forehead. 

We like the Fidlock SNAP magnetic closure on the chin strap and adjustable side buckles.

Read our full test review of the Troy Lee Designs A3 helmet

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Endura MT500

Takes impact protection to the next level

Weight: 348g | Sizes: S-M, M-L, L-XL | Rating: 9/10

Pro: Ticks all the important boxes Con: Not quite as finely finished as rivals

The MT500 is packed to the gills with features, including an adjustable peak, anti-bacterial padding, eyewear dock as well as a clip-off accessory mount for a headlight or helmet-cam.

The peak lifts far enough up to store goggles and the straps are held securely under the peak edges and a large (removable) clip at the back. Underneath the slightly dour looks there’s a cracking trail helmet, we just wish Endura would add a bit of bling to the skin.

We found the MT500 to be a little short front-to-back but it’s standard width and feels really comfortable even with the dial snugged up tight. When it comes to construction and details, it ticks all the boxes.

Read our full test review of the Endura MT500 helmet

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Smith Engage MIPS helmet

A top quality helmet at a mid-range price

Weight: 344g | Colours: Orange, White, Black | Sizes: S, M, L, XL | Rating: 9/10

Pros: Excellent stability, comfort and styling Cons: Ventilation could be better

We’ve always liked Smith’s range of sensibly designed, uniquely styled helmets, and the Engage brings these qualities to a lower price point. You still get the MIPS liner, designed to reduce injuries from rotational impacts, and snug, secure, 360º retention system with dial adjustment.

It doesn’t boast quite the same level of venting as more expensive Smith helmets – the more basic construction means more material is needed – but it’s still cool enough for most riders and most temperatures.

Read our full test review of Smith Engage MIPS helmet

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How we test the best mountain bike helmets

All mountain bike helmets pass the current CE test so we’re taken it as read that they’ll work if you clonk your head on a passing tree. However, there’s currently no test for fit, venting or adjustability, which is why we’ve focused on these things when testing. To test the fit, we measured the shape of each one but that doesn’t reveal any hot spots, which is why we did lots of in-field testing, to test the true comfort. Riding hard we could also gauge the breathability and venting of the helmets.

Key features of the best mountain bike helmets:

The best mountain bike helmets sit a bit deeper on your head, extending down the nape of the neck, and they have extra coverage around the temples. Lots of helmets now incorporate some kind of rotational proection device, such as a MIPs liner, to reduce the risk of concussion. This can also be in the form of integrated reinforcement or crumple technology. There’s normally a visor, or peak, that you’ll be able to adjust up and down, and you may even see features such as integrated adapters to mount a POV cam or light, magnetic buckle closures, goggle strap clips and a storage bag.

Any bike helmet will work off-road but if you’re reading this, chances are you’re a trail warrior and you’ll want something a little bit more specific. A modern trail helmet will sit a bit deeper on your head and have extra meat over the temples and down the back, for greater protection. It’s likely to have some sort of built-in rotational device like a MIPs liner, to reduce the risk of concussion or some integrated reinforcement or crumple technology. You’ll get a visor that you’ll be able to adjust it up and down and you may even see integrated adapters to mount a head cam or light, magnetic closures, goggle strap clips and a storage bag.

Fully loaded, a good trail helmet isn’t going to be cheap but we believe it’s a small price to pay for something that could save your life.

Due to the trickle-down effect you will see some high-end features included on budget helmets but we’ve focused on the top-tier simply because that’s where there’s the greatest choice. These helmets are more refined, harder wearing and look pretty sick too.

How to find your helmet size

Get hold of a fabric or paper tape measure if possible. If you don’t have one, don’t try and wrap a metal tape measure around your noggin, it doesn’t work – believe us. In the absence of a fabric/paper tape measure, find some string and wrap that around your head and note its length.

Whereabouts to measure around your head? Essentially around the widest (biggest circumference) part of your head. Around your forehead and around the most prominent bit of the back of your head. Note down the measurement in centimetres. All helmets have size ranges and with your head measured it’s then easy enough to find which sizing has your head size covered.

How often should you replace a helmet?

You should replace a helmet after any slightly significant impact or crash. A lot of helmet companies offer crash replacement schemes so it’s worth checking out their websites for info about such things.

In terms of general lifespan, it’s typically advised that you should think about replacing your helmet every two to three years. Some companies in the past have stated a longer term than this but we’d feel a bit iffy using a helmet that’s had more than three years proper trail riding use. General wear and tear as well as things like UV degradation can have negative affects on the performance and reliability of your helmet.

Best mountain bike helmets protection standards

All bike helmets sold in the UK need certification. This means helmets must meet certain fixed test criteria like impact velocities, roll-off tests, and strap system strengths. This is a minimum and many modern helmets surpass these requirements by incorporating composite materials into sub frames or “roll cages” for extra protection.

Crash replacement schemes

If your helmet is involved in an accident, most manufacturers offer a reduced price crash replacement scheme. With proof of original purchase, these programmes can save you up to 50% on an expensive replacement lid.

EPS

EPS (expanded polystyrene) foam is at the core of every bike helmet and works exactly like a crumple zone in a car. Modern helmets use different densities and some are even reinforced with an internal mesh or webbing.

MIPS

Multi-directional Impact Protection System is a patented protective liner that slides when your head hits the ground, reducing the force of them impact and likelihood of a concussion or brain injury. MIPs is a branded product so several manufacturers do their own version usually with an equally ambiguous abbreviation.

Padding

Padding thickness and density has a significant effect on sweat absorption, cooling and comfort. Thicker internal padding may run a little hotter but you’re less likely to get sweat running down your neck and the helmet will generally feel more comfortable. Channels are often formed into padding to improve air flow and speed up drying.

Retention device

Like in a baseball cap, a retention device allows you to adjust the fit of the helmet. Most use a dial, which allows you to tune the tension/size with one hand while riding. You can also adjust the height using press-studs or a sliding clip.

Shell

To reduce dings and dents, the EPS it’s covered with a thin plastic micro-shell. This is usually in-moulded with the foam during the manufacturing process and can be one or several pieces.

Ventilation

Vents at the front of the helmet allow air to flow in and those at the back let it flow out again. Generally, the more the merrier but the shape and angle of the vents and how they integrate with the peak is key to keeping cool.

Visor/Peak

Being able to tilt the visor up means it doesn’t block your vision when riding with you head down but it also allows you to ‘park’ your goggles underneath. To hold the goggle strap securely, most helmets have a channel called a strap-gutter round the back but we also see clips or small tethers.

Goggle parking/strap gutter

On some helmets the visor can be tilted up so you can ‘park’ goggles underneath when you’re not using them. Usually this feature comes hand in hand with a strap gutter – a shallow channel on the back of the helmet that holds the strap in place.

Bottom wrapping

To add extra protection to the lower edge of the EPS the micro-shell often wraps under the bottom of the helmet.

Sizing

Helmets come in various sizes. Small, medium and large is pretty standard but you also see overlapping sizes like S/M and M/L. One company’s medium can also be another’s large and some helmets are long and thin, while others are short and squat. All of which means there’s no consistency in sizing or fit and you should always try before buying.