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, however you ride.
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.
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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.
Coverage and 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 around 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 bicycle helmets use some form of expanded polystyrene or ‘EPS’ foam to provide cushioning in the event of an impact, often formed around a core of other, tougher material. 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 any 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 (that's multi-directional impact protection system), which uses a floating plastic liner in between your head and the shell of the helmet that reduces the amount of rotational force that is transmitted to your brain during a crash. Rotational force is responsible for a large number of injuries through brain damage, so while it's more expensive (and that's reflected in retail prices), many manufacturers now incorporate MIPS into their helmets.
Most bicycle helmets now have a hard plastic outer moulded to the soft EPS core. This is known as in-moulding and it provides protection against minor bumps and scratches that would otherwise degrade the core. On cheaper helmets, this tends to be limited to the outside and top of the helmet. More expensive, fully in-moulded helmets have the plastic protection extend down and around the rim, which is much more effective in fending off damage.
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 having channels that help air flow in through the front, over your head and letting all that warm air out of the back is the key. Look for big vents on the front and rear, with deep channels on the inside of the lid.
Like any item designed to be worn, how well a helmet fits is very much dependent on your own shape. Many people tend to get on with certain brands that tend towards a particular shape, but this is very much a case of trial and error, so go to your local bike shop or ask your friends to see if you can try on different lids for size. The main thing is that you can get the helmet sitting properly on your head without any pressure points or it being able to move about unduly.
Most helmets will have a retention system of some kind that will allow you to tighten and adjust how it fits onto your head. Most of these will tighten and loosen around the circumference of your head, though some also adjust in other ways. However it works, make sure you can operate it easily in gloves and that it doesn’t trap or pinch hair and flesh. Ensure that you can adjust the straps to get a solid fit that’s not restrictive and that when fully adjusted you have clear, unobstructed vision, 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 wear glasses when you ride, make sure they fit comfortably with it.
While weight might seem like a minor consideration compared with the other categories, 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.
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 action camera mounts into their helmet designs. These allow a super 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 a peak that lifts up high enough for you to be able to fit the goggles underneath when you don’t want to wear them 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 2016
Best overall: Giant Rail
£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 top keep them secure. All in all, the Rail has become our go-to lid.
Best for extra protection: Scott Stego MIPS
£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 special liner inside the helmet, the MIPS system helps prevent brain damage in a crash by reducing the rotational forces that can cause brain injuries. It only comes at a 15-20g weight penalty, so there are barely any drawbacks to the system.
Elsewhere, the Stego has a squared off profile which might not to be the taste of everyone, but it does gives plenty of coverage on your temples and the back of your head. It’s also a very comfy lid with plenty of airflow thanks to large channels that direct air over your nead. The fully in-moulded shell also means that it puts up with the rough and tumble of mountain biking life very well too.
Best for coverage and cooling: Specialized Ambush
£120 / $180 / AU$250
If you need a trail helmet that’s got plenty of coverage but won’t boil your brains when the sun is shining, the Ambush is well work a look.
At 316g it’s also respectably light and the rounded internal profile is comfy, though some riders did find it a touch narrow towards the front. We also really liked the retention system, which tightens evenly around your head, rather than just the rear. That means no uncomfortable pinch points and a highly secure fit.
In keeping with modern lids, the big peak also has enough space to accommodate goggles, while clever venting and design helps increase airflow over whatever eyewear you choose, meaning less misting up.
Best for riders on a budget: Scott Watu
£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 fully in-moulded shell, which 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.
Best for women: Bontrager Quantum WSD
£50 / $65 / AU$70
With a fully in-moulded shell and just-so padding, the Quantum is a great choice for any female rider on a budget. The fit is superglue-secure and there’s even space in the retention system to allow anyone that chooses to rock a ponytail to route it through without problem.
There’s a minimal yet comfortable level of padding and the retention dial is easy to use and distributes pressure evenly around your head. A removable but substantial peak helps keep the weather out, meaning this lid can transfer over to road use if needs be.