The best mountain bike helmets are primarily protection, but are also comfortable and even stylish. We've tried and tested a huge selection to find out which offers the perfect blend, at various price points.

A good helmet is an essential piece of kit – you can ride without gloves, a jacket… pants even, but not a lid. The best mountain bike helmets do it all, blend style with comfort, and introduce features like visors or POV camera mounts. And all the while deliver great protection.

We’ve extensively tested and reviewed all the best MTB helmets on the market, only the ones worth buying make it through to this stage.

In this guide you’ll find 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.

Troy Lee Designs A3 helmet

Troy Lee makes the best helmet on the market in the A3: comfort, protection and style in one neat package

1. Troy Lee Designs A3

Best overall mountain bike helmet

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

Reasons to buy:

  • Stunning looks from the TLD paintshop, and superb comfort
  • Great protection, with EPS and EPP core and MIPS liner

Reasons to avoid:

  • You’ll need deep pockets (unless it’s on sale, as it is right now!)

It’s fair to say the A3 is the best fitting and most comfortable helmet on sale. It’s extremely well padded, which does reduce the ventilation somewhat, but it’s not overly hot or sweaty like the A1.

The A3 is secured in place by a 360° retention band that encircles your head and is height adjustable. It’s really effective at stopping any wobble, and there’s silicone brow pad too (different sizes are included) that’ll channel away sweat… although it can stick to your head a bit).

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.

A great looking helmet that’s amazingly comfortable and packed with features, but demands a premium price.

Read our full review of the Troy Lee Designs A3 helmet

Bell Sixer MIPS

With vents galore, Bell’s Sixer MIPS is our summer helmet of choice

2. Bell Sixer MIPS

Best for ventilation / summer riding

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

Reasons to buy:

  • Cools well thanks to superb ventilation and air flow
  • Great protection with two layers of EPS and a MIPS liner

Reasons to avoid:

  • Slightly fiddly vertical retention adjustment

The Bell Sixer is made using something called Progressive Layering, where two densities of foam overlap to better protect your head. On the outside and under the regular nylon shell is a hard layer of EPS to stop anything penetrating, while inside is a softer layer which crumples more easily to spread the load. You also get a MIPS layer to help dissipate rotational forces.

Above all, venting is excellent on the Bell Sixer. There’s a large slit over the temple area and intake ports below, while long channels run the whole length of the helmet. At the back are big exhaust ports to draw the air through, making this helmet ideal for warm weather. There’s even a two-piece pad with the X-Static treatment inside to fend off pongs.

Read our full test review of Bell Sixer MIPS

Photo of green Specialized Camber mountain bike helmet

If you don’t mind a fixed peak, the Camber kills it for value and comfort

3. Specialized Camber

Best value helmet

Weight: 392g | Sizes: S, M, L | Rating: 9/10

Reasons to buy:

  • Great value for money
  • Good ventilation
  • Secure on-board glasses storage
  • Lightweight and comfortable

Reasons to avoid:

  • Minimal padding with no antibacterial treatment
  • Less secure on rough terrain and a fixed visor

The Camber is a better value version of the Specialized Ambush 2, as such it gets lots of the high end features but without the cost. There’s a single layer EPS layer inside, with the added protection of a lightweight MIPS SL Liner.

Padding is minimal, but this actually works really well inside the Camber because the contact area is large and it spreads the load. The helmet features a really neat Integrated Fit system adjusted via a ratchet at the back, and that means Specialized has really nailed the details and the comfort too. It’s lightweight and cracking value for money.

Read our full review of the Specialized Camber helmet

Photo of black Fox Dropframe MIPS Mountain Bike helmet

The Dropframe boasts extra coverage, but there’s barely a weight penalty, and comfort is great too

4. Fox Dropframe MIPS

Best mountain bike helmet for extra protection and coverage

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

Reasons to buy:

  • Great extra coverage
  • Still plenty of ventilation
  • Lightweight design and a MIPS liner

Reasons to avoid:

  • Visor isn’t adjustable

The Fox Dropframe is the best full face helmet with extra protection. Think of it as a half-way house between an open shell and a full-face, with more coverage on the side of your jaw, around the ear and at the back of the neck. It’s a divisive look, but the safety benefits can’t be denied and it’s also extremely lightweight despite the superior coverage.

Comfort and stability are first rate, and the Dropframe is super easy to put on because the sides flex slightly letting you pull them apart to clear your ears. Amazingly, the helmet boasts really good ventilation too, there are 15 ports and it’s breezy inside. This helmet fits like a glove, you could wear it all day.

Read our full review of the Fox Dropframe MIPS helmet

Fox Speedframe Pro

The Fox Speedframe Pro is a terrific all-rounder, protection is first rate and it fits well too

5. Fox Speedframe Pro

Best balance of comfort and protection

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

Reasons to buy:

  • Speedframe looks brilliant, which shouldn’t matter but we all want to look cool, right?!
  • Great protection wuth dual density EPS

Reasons to avoid:

  • Liner moves around a little
  • Internal shape doesn’t suit rounder heads

Fox uses its own Varizorb EPS liner to bolster protection, with two EPS layers joined internally to act as crumple zones and dissipate energy in a crash. There’s also the obligatory MIPS liner to offset additional 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.

Looks great, feels great, lightweight… Fox has nailed it with the Speedframe Pro.

Read our full test review of Fox Speedframe Pro helmet

Photo of black and turquoise Giro Source MIPS Women's mountain bike helmet

The Giro Source is an excellent helmet, with good protection and comfort… the women’s moniker just means it comes in smaller sizes

6. Giro Women’s Source MIPS

Best women’s mountain bike helmet

Weight: 347g | Sizes: S, M | Rating: 9/10

Reasons to buy:

  • Uses a MIPS liner and there’s good all round and extended coverage
  • Sweat-absorbing padding
  • Indexed adjustment on the visor

Reasons to avoid:

  • 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 you to park my goggles under it. The shell extends down over the temples and at the back, giving it extra coverage.

It fits really well, it’s comfortable, and the retention device is easy to adjust while riding. The venting is good, and it holds goggles securely in place. While this version of the helmet is labelled women-specific, it’s no different to the Giro Source MIPS: the only change is a unique selection of colours and a smaller size range offering.

Leatt MTB Helmet 3.0

Leatt has made a super-versatile helmet in its 3.0, full face, trail lid or extra protection… the choice is yours

7. Leatt MTB Helmet 3.0

Best convertible mountain bike helmet

Weight: 462g open-face / 587g with ears / 718g full-face | Sizes: S, M, L | Rating: 10/10

Reasons to buy:

  • The 3-in-1 design means it’s really versatile
  • Works out good value compared to three individual helmets
  • It’s comfortable, stable, and easy to convert

Reasons to avoid:

  • Quite difficult to take on and off with chinbar fitted
  • It’s heavier than a specific open-face
  • Glasses rattle against the underside of the brow

The Leatt MTB 3.0 is the best realised convertible helmet. By that we mean it can work as a full face downhill lid with full face coverage and a chin bar: an enduro helmet with extra protection around the sides: and a regular trail lid for maximum breathability.

It’s stable in each mode, and comfortable to wear thanks to good padding, and the venting is decent too. The MTB 3.0 fits together fairly easily too, so if you regularly ride at the bike park, on regular trails and ride enduro, it’s actually a brilliant proposition.

Read our full review of the Leatt MTB Helmet 3.0

Scott Tago Plus helmet

Mips protection comes on many modern mountain bike helmets

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.

Indexed visor adjustment

Indexed visor adjustment let’s you push the peak up if you want to park your goggles

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.

Lazer Coyote kineticore helmet

Fidlock magnetic closure on a chinstrap. These are quick and easy to fasten and open.

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 (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.

Specialized Tactic 4 MIPS interior

The Mips liner is designed to slide within the helmet in a crash, reducing the rotational and acceleration forces on your brain.


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.

The inside of a Koroyd-equipped helmet

The inside of a Koroyd-equipped helmet


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 band

The retention band is usually adjusted via a dial at the rear.

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.

Giro Source helmet

Flip a helmet over and you can see the EPS (expanded polystyrene) inner.


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.


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.

Detail showing visor in up position on Endura MT500 MIPS helmet

This visor position is adjustable, with ample room for stowing glasses or goggles


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.

goggles on a mountain bike helmet

If you wear goggles sometimes, it’s good to check the lid will accommodate them properly

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.

Scott Tago Plus helmet

An example of a bottom-wrapped helmet

Bottom wrapping

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


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.