The are many different types of mountain bike helmets on the market today, each specifically targeted at a certain type of rider. This article outlines the key types of helmet, the features, and what kind of rider the helmet type is for.
Typical Helmet Construction
A basic mountain bike helmet has an outer shell, a crushable foam layer- such as expanded polystyrene- and a comfort liner, making it comfortable to wear. The outer shell protects the head from direct physical impact, such as a skull fracture. The inner lining protects the head from concussions and head trauma. As the level of protection increases, the materials and protective systems improve.
Rotational Impact Reduction Systems
As technology improves, mountain bike helmets are seeing more systems that reduce rotational impact and provide more excellent concussion prevention. These systems, such as MIPS and Turbine 360, reduce the risk of head trauma due to rotational forces such as when a riders head gets hit from an angle or twisted as they crash. For more information on rotational impact reduction systems, check out our top 15 helmets with MIPS.
Half-Shell Mountain Bike Helmets
A half shell helmet is the minimalist's helmet with a considerable amount of ventilation while still offering full head and brain protection. The design is very similar to the standard road helmet, except it features a visor and slightly more protection around the rear of the head. Half shell MTB helmets have the most breathable and lightweight design of all the helmets, due to less material surrounding the back of the head.
Half-shell helmets are designed for cross country or trail riding, where the benefits of ventilation and lightweight materials supersede the necessity for improved back of head protection. For most riders, particularly beginners or riders not intending to ride any technical trails, this helmet would be most comfortable.
Open-Faced Mountain Bike Helmets
An open-faced helmet is similar to the half-shell but offers deeper coverage at the rear of the head. Although it has slightly less ventilation, the design is still very breathable and is very lightweight. The primary advantage is that the back of the head is protected slightly more, providing a more 'snug' fit. It offers more protection from sharp objects such as sharp rocks or sticks from getting through.
Check out our comparison of the Giro Manifest vs the Giro Montaro.
This helmet is typical for trail riders and good for anyone who wants a slightly more protective helmet than the half-shell while maintaining good ventilation and lower weights. This would be the recommended style for any rider heading to even slightly technical terrain, beginners through to advanced riders.
Drop Frame Mountain Bike Helmet
A drop frame helmet is the next step closer to the full face while still allowing the breathability of an open face helmet. The drop frame provides greater coverage around the back of the head and extends over the ears, but does not have the chin bar that the full-face helmet offers.
Ideal for the rider looking for slightly more protection than the standard open face helmet, but also looking for the ventilation that an open face helmet provides.
Full Face Mountain Bike Helmet
The full-face helmet provides the maximum protection a helmet can provide, with full coverage around the rear of the head and a chin guard, which protects the chin and face from sustaining damage from crashes and front-on collision. With this comes extra weight, and significantly less ventilation than an open-face helmet.
Unless the rider intends to ride downhill only, the full face will likely be too hot for comfortable riding. The weight and lack of ventilation of a full-face mean that long-term comfort is sacrificed when a certain amount of exertion is required- say for climbing up a hill.
Recommended for riders with access to a chairlift, shuttles, hikes (any opportunity to take the helmet off or require little exertion) to get up the hill, and require greater protection for the downhill.
Detachable Full-Face Mountain Bike Helmet
Since full-face protection is not required while climbing uphill (as you are unlikely to crash at high speeds heading up the hill), the detachable chin bar means that the bottom portion of the helmet can be removed transforming the full-face helmet into an open-face helmet. This assists with improved ventilation and reduces the weight for the ascent.
The chin guard can be reattached for the descent, providing full protection again. The detachment process is simple, usually just a buckle or clip system, and is very securely reattached using the same process — no need to carry tools to piece the helmet back together again on the ride with you.
Check out our article on the best convertible helmets for more on detachable full face helmets.
For a rider that does both technical downhill rides requiring maximum protection, as well as climbing or riding some distance, the detachable mountain bike helmet is the best of both worlds.
Half Dome Helmets
A half dome isn't typically recommended for a mountain bike rider. It is heavy and provides little in terms of protection and ventilation. However, many like the looks of the helmet and often make an appearance at the trick or skate park. Better than nothing for protection, but not generally recommended.
Other Types of Helmets
Mountain bike helmets have had a lot of research and development over the years and are tailor-made for the trails. Other helmets, say a ski helmet or a road riding helmet, would not be suitable for the style of riding (or crashing) that mountain biking entails.
Road helmets are designed for a forward-moving crash on pavement and have limited protection towards the rear of the head. For more information on why not to use a road bike helmet, see here.
In summary, it comes down to a weigh-off between protection and comfort. A full-face helmet will provide plenty of protection but will be somewhat uncomfortable for riding up large hills all the time.
A full-face will be much better suited to the downhill and enduro rider, whereas an open face or half-shell helmet is better for a rider who climbs often or rides longer distances.
The difference between a half-shell and a standard open-face helmet will not make a huge difference in your riding but having greater protection around the rear of the head may give you peace of mind.