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 to boost protection.

Unless you care about every single gram or really want ultimate cooling, that makes them a sensible bet for the majority of 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 to improve on this.

One such technology is MIPS (multi-directional impact protection system), which uses a floating plastic liner between the head and the EPS structure, which reduces the amount of rotational force transmitted to the 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 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 extend the plastic protection 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 pushing really hard.

Happily, thanks to the 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 airflow in through the front, over the head and out the back that makes 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.

If possible, bearing in mind the latest Covid-19 guidance, go to your local bike shop to see how you get on with different lids or ask your friends 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. Many of these will tighten and loosen around the circumference of the head, although some also adjust in other ways.

Robin Weaver

However it works, make sure you can operate the system easily in gloves and that it doesn’t trap hair or pinch flesh.

Also 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 move about as you ride, too.

Convertibility

Andy Lloyd / Immediate Media

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 in 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, though.

Andy Lloyd / Immediate Media

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 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 at the back to keep them secure.

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