Best mountain bike helmets for trail riding

Buyer's guide to trail lids, now updated with 2017 recommendations

Protecting your head is vital in the rough and tumble world of mountain biking, where crashes can be an all-too frequent an occurrence. That’s why getting the best mountain bike helmet possible is hugely important to staying safe and comfortable.

We’ve rounded up our pick of the best trail helmets currently on sale, plus our advice on what to look for when you’re buying a new lid.

So what do I need to look for?

The best mountain bike trail helmets manage to balance the often-competing needs of protection, ventilation, comfort and weight. 

Protection

Helped by the rise in popularity of enduro racing, many open-face lids now offer greater coverage around the back of the head and the temples than cross-country or road-style helmets, helping boost protection. Unless you care about every single gram or really want ultimate cooling, that makes them a sensible bet for most riders.

Most bike helmets use some form of expanded polystyrene, or ‘EPS foam', formed around a core of another, tougher material to provide cushioning in the event of an impact. The foam crushes when it’s struck, spreading and delaying the force of the impact being transmitted to the wearer, hopefully to a level that will prevent injury.

While the impact resistance of helmets is covered by a number of test standards to ensure they perform when they’re needed, manufacturers have been introducing extra technology to try and improve on this. One such technology is MIPS (multi-directional impact protection system), which uses a floating plastic liner between your head and the EPS structure that reduces the amount of rotational force transmitted to your brain during a crash. Rotational force is responsible for a large number of injuries, including brain damage, so while it makes manufacturing, and thus retail, prices more expensive, many manufacturers now incorporate MIPS into their helmets.

Most bicycle helmets now have a hard plastic outer moulded to the EPS structure. This is known as in-moulding and it provides protection against minor bumps and scratches that would otherwise damage the EPS. On cheaper helmets, this tends to be limited to the top and sides of the helmet. More expensive, fully in-moulded helmets have the plastic protection extend down and around the rim, making it much more effective at fending off damage.

Ventilation

While the extra coverage of trail-style helmets is more than welcome, it does get in the way of airflow, which can mean a much warmer and sweatier head in hot weather or when you’re really pushing hard. Happily, thanks to increasingly clever use of materials and design, it’s now possible to make a lid that’s almost as cool as a conventional design. Having lots of vents is important, but it’s the internal channels that help air flow in through the front, over your head and out the back that make all the difference. Look for big vents on the front and rear, with deep channels on the inside of the lid.

Comfort

How well a helmet fits will depend on the size and shape of your head. Many people tend to get on with certain brands that use a particular shape, but finding the right one is very much a case of trial and error, so go to your local bike shop to see how you get on with different lids or ask your friends to see if you can try theirs. The main thing is to ensure you can get the helmet sitting securely on your head so there are no pressure points or undue movement. 

Most helmets will have a retention system of some kind to allow you to adjust how tightly it fits onto your head. Most of these will tighten and loosen around the circumference of your head, although some also adjust in other ways. However it works, make sure you can operate the system easily in gloves and that it doesn’t trap hair or pinch flesh. Ensure that you can adjust the straps to get a solid fit that’s not restrictive and that when fully adjusted you have a clear, unobstructed view, especially when you’re in an aggressive, head-down riding position. Check that the peak can be adjusted so that it keeps the sun out of your eyes without getting in the way or flapping about when you ride. If you like to ride wearing glasses, make sure they fit comfortably with the lid.

Weight

While weight might seem like a minor consideration compared with a helmet's other characteristics, a lightweight helmet will be a much more pleasant place to be after a long day on the bike. A light lid is much less likely to try to move about as you ride too.

Convertibility 

A number of helmets on the market now come with a chin guard that can be removed. This is largely in response to the growth of enduro racing, where long climbs benefit an open-face lid to help you breathe and stay cool, while gnarly descents mean the additional protection from a full-face-style lid is desirable. With a removable chin guard, riders get the best of both worlds.

The compromise is often weight, because if the helmet has full ASTM downhill certification (so it can be used as a DH race helmet), there needs to be extra protection built in. Not all of the convertible helmets meet this standard, however.

Whether you choose a convertible helmet is up to you, but we're definitely seeing more on the trails these days.

Anything else I might need to know?

If you love to record and share your rides online, then you’ll be pleased to know that more and more manufacturers are integrating removable camera mounts into their helmets. These allow a secure fitting for your camera, but also mean you can go back to having an unfettered helmet when you want to.

Many enduro-style lids now also allow you to use goggles to provide almost impregnable eye protection. Look for helmets with a peak that lifts up high enough for you to be able to fit the goggles underneath and a strap of some kind of the back to keep them secure.

Now you know what to look out for, here are five of the best mountain bike trail helmets out there…

Best mountain bike helmets 2017

Giant Rail – mid priced but high performance

BikeRadar score5/5

Giant Rail: packed with smart features
Giant Rail: packed with smart features

  • Price: £80 / $130 / AU$170

Giant might not be the first brand you’d think about when it comes to helmets, but the Rail manages to offer all the extra coverage protection, low weight and cooling airflow of high-end trail lids but without the premium price tag.

Lots of vents and clever internal channelling mean it’s cooler than a lot of road bike lids that we’ve tested and we found the shape to be highly comfortable too. The retention system is easy to adjust and even the ham-handed rider won’t be able to wreck it.

It’s packed with smart features too, such as a flat spot for attaching a stick-on GoPro mount and a visor that can be lifted up high enough to accommodate goggles, plus a strap on the back to keep them secure. All in all, the Rail has become our go-to lid.

Giro Switchblade – the ultimate convertible lid?

BikeRadar score5/5

Giro Switchblade without chin guard: our favourite enduro lid at this time
Giro Switchblade without chin guard: our favourite enduro lid at this time

  • Price: £250 / $250 

The Switchblade is Giro's convertible helmet, meaning it has a detachable chin guard for the descents. The chin guard clips on to the helmet relatively easily and can be stowed on the outside of a pack.

With full ASTM-level protection with the chin guard in place, this is as protective as convertible lids come – it's safe enough to be certified for full DH use. The flip side is that it's not quite as well ventilated as some other convertible helmets.

Giro Switchblade with chin guard
Giro Switchblade with chin guard

Inside it's a very comfortable place to be, with plenty of well-placed padding. Without the guard the sides of the helmet drop really deep and the vents aren't massive, so it's still warm on the climbs.

The visor is large and goggles sit nicely within the helmet. Full-face or not, it's our favourite enduro lid at this time.

Scott Stego MIPS – great all-round trail lid

BikeRadar score4.5/5

Scott Stego MIPS: provides plenty of coverage to your temples and the back of your head
Scott Stego MIPS: provides plenty of coverage to your temples and the back of your head

  • Price: £120 / $190 / AU$230

We’ve been big fans of the Stego ever since it was launched, but this MIPS version uses clever technology to keep you safer than ever. Using a plastic liner inside the helmet, the MIPS system reduces the rotational forces that can cause brain injuries. It only comes with a 15-20g weight penalty, so there are barely any drawbacks to the system.

Elsewhere, the Stego has a squared off profile that might not to be the taste of everyone, but it does give plenty of coverage to your temples and the back of your head, making it ideal for anyone looking for a lighter trail lid with a little extra protection. It’s also a very comfy lid with plenty of airflow thanks to large channels that direct air over your head. The fully in-moulded shell also means that it puts up with the rough and tumble of mountain biking life very well too.

POC Tectal – a top-end, breezy helmet

BikeRadar score4/5

POC Tectal: has fit and ventilation that's up there with the best
POC Tectal: has fit and ventilation that's up there with the best

  • Price: £155 / $190

If you need a trail helmet that’s got plenty of coverage but won’t boil your brains when the climbs are long and hot, take a look at POC's Tectal.

We found both the fit and ventilation to be up there with the best – if it suits your head, then it's likely to be one of the most comfortable and airy lids you can get. With a deep drop at the back of the helmet and plenty of material round the front, there's also a lot of protection on offer.

The visor is just big enough to give reasonable rain and sun protection, and it has a decent range of adjustment too.

It's not a cheap helmet, nor does it have MIPS, but the finish and fit is great, and there's internal reinforcement for safety and Recco reflectors for added piece of mind if it all goes wrong.

Scott Watu – our favourite budget choice

Scott Watu: spot-on for any mountain biker on a budget
Scott Watu: spot-on for any mountain biker on a budget

BikeRadar score4.5/5
  • Price: £35 / $45 / AU$50

While one look at the price tag might leave you thinking the Watu is a cheap, leisure-orientated lid, it’s actually spot on for any mountain biker on a budget.

The 16 vents give decent airflow over your head to large exhaust ports at the rear, while the one-size-fits all design works very well for everyone save those at the extremes of size.

At this price it seems churlish to bemoan the lack of a fully in-moulded shell, even if it does leave the underside of the helmet vulnerable to damage. Seeing as the rest of the lid is so well thought out, we’re more than willing to forgive it that.

Scott no longer lists the Watu as for sale, but it's still available at a wide number of retailers and as it's so good, we're keeping it in this list for now!

To stay current, this article has been updated since it was first published so some comments below may be out of date — last updated 11 October 2017

Tom Marvin

Technical Editor, Tech Hub, UK
Tom's been riding for 15 years, and has always chopped and changed bikes as soon as his budget allowed. He's most at home in the big mountains, having spent nigh on 30 weeks riding the Alps, as well as having lived a stone's throw from the Scottish Highlands for four years. Tom also enjoys racing events like the Strathpuffer and the Trans Nepal.
  • Discipline: Mountain
  • Preferred Terrain: Steep and super tech or fast and flowy
  • Current Bikes: Canyon Spectral, Pivot Mach 429SL, Mondraker Vantage R +
  • Dream Bike: Transition Scout
  • Beer of Choice: Gin & tonic
  • Location: Bristol, UK

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