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Bicycle Helmet Buying Guide - GO Outdoors

Helmets are an essential piece of kit to protect your head if you fall off your bike. We and the Highway Code would strongly recommend wearing a helmet when cycling – it really could save your life. The extra security also gives you the peace of mind to go that little bit faster and have even more fun!

There are different types of helmet for road, mountain bike and BMX riders. Serious riders will want a helmet designed for their specific discipline but you can choose pretty much any of them if you're just riding to get around, keep fit or have a bit of fun.

  • Helmet Construction 
  • General Features 
  • Road Helmets 
  • MTB Helmets 
  • BMX Helmets 
  • Kids’ Helmets 
  • Fitting a Helmet 
  • Replacing a Helmet

Bicycle helmet construction

All helmets are constructed from three distinct layers:

Outer Shell

This part is generally made from smooth, hard polycarbonates and defines the structure of the helmet. It provides a nice overall finish, either matte or shiny, to the helmet once painted up. In the event of a crash, this smooth layer helps the helmet skid more easily on impact, rather than bumping and jerking the neck. It also helps keep the helmet together after the first impact to maintain protection in case of any further impacts.

BMX helmets have to withstand regular small crashes and tend to have a harder, more substantial outer shell constructed from a fibreglass blend. It is heavier, but gives BMX helmets a longer lifespan than standard helmets that should be replaced after every crash, however minor.

Foam Core

The foam core is what absorbs impacts, protecting your head from damage. Generally, expanded polystyrene (EPS) foam is used but you might also see expanded polypropylene (EPP) or expanded polyurethane (EPS). EPP and EPS are not as common because they are heavier and more expensive. Some more advanced helmets mold this foam core directly into the outer shell rather than attaching the outer shell to a pre-molded core to save weight and improve structural integrity.


The inside of the foam core is lined with soft foam or gel pads for comfort and to help ensure a tight, secure fit. These pads do not contribute to impact protection. They are often removable to aid with cleaning. High-end models sometimes add antibacterial and moisture-wicking materials to help control odour and sweat.

General Features

There are lots of differences between the different categories of helmet but there are some general features to look out for nonetheless.


All our cycle helmets meet the required CE EN1078 European safety standard that ensures a suitable level of protection for most riding. High-end helmets will exceed this rating and provide even greater protection. There are also certain disciplines, such as downhill mountain biking, which involve a higher likelihood of serious crashes and demand a higher level of protection than the minimum safety standard. Full-face mountain bike helmets offer the highest level of protection for more dangerous riding.


Like almost all cycling components, the lighter the better. High-end helmets use advanced materials and design to reduce weight while maintaining full protection. Reducing weight anywhere on your cycling setup, including your helmet, helps you climb and accelerate faster and generally conserve energy as you ride. A lighter helmet limits fatigue for your neck, which can be considerable issue if you are in an aerodynamic position on road bike. Maneuverability for your head is also improved with a lighter helmet, helping you keep aware of everything that's going on around you and spot any potential hazards coming up.


Most helmets have vents to let airflow pass over your head, keeping you cool and carrying away excess moisture. The vents are cleverly designed and located so that the helmet still provides sufficient protection despite essentially being full of holes. High-end helmets generally offer superior ventilation, using trickier production methods to cram more vents in while maintaining full structural integrity. These more advanced helmets also benefit from aerodynamic research to maximise airflow through the helmet with internal channels which guide air from specific intake vents, across the head, and out through exhaust vents.


The most important part of buying a helmet is choosing one that fits well. If a helmet is too small, it will sit too high and fail to protect the lower part of your head. If a helmet is too big, it will not be securely fitted to your head and could shift during a crash and expose your head to damage. It’s not just about sizing, however. We all have different shaped heads and some helmets do fit some people better than others depending on the manufacturer. More information about fitting a helmet can be found below.

Retention systems:

The retention system is what tightens the helmet to your head for a secure fit. The simplest helmets - usually BMX and kids helmets - just use the chin strap. Other helmets will include a ratchet at the rear of the helmet that slides in and out to adjust the fit for comfort and security. The best retention systems are micro-adjustable and can be used with a single hand for mid-ride tweaks. This usually involves an easy-to-use dial ratchet that you simply twist to adjust. Some systems adjust in multiple directions to adapt the fit for your particular head shape.


Fit, weight and ventilation both contribute to the overall comfort of the helmet. Helmets higher up the price range offer better comfort thanks to improved padding, straps, retention systems and ergonomic design.

Road cycling helmets

Like most things in road cycling, the emphasis on road helmets is light weight and aerodynamics. Ventilation is also key to help with temperature control in hot weather and during hard efforts. The benefit of good ventilation is particularly felt on climbs when you aren't travelling as fast and you aren't generating as much of a cooling breeze.

As you go higher up the range of road helmets, you'll see more distinctive designs that offer lower weights, better ventilation and superior aerodynamic performance. More attention will be paid to details like the padding and retention system for greater comfort. The use of higher-quality materials will give helmet a more luxurious feel and a sleeker finish.

Road helmets aren't just for lycra-clad racers - they're equally suitable for casual riders, commuters and cross-country mountain biking.

Mountain bike helmets

Mountain Bike helmets are designed with greater coverage than road helmets to help protect against rugged off-road conditions. In particular, MTB helmets tend to extend lower at the rear to protect the back of the head. One key difference with road helmets is the use of a peak. This helps keep the sun, rain and mud out of your eyes so you can clearly see the terrain ahead. It also acts as a first line of defence against any incoming branches!

Different levels of protections are available, all the way up to full-face helmets that protect the chin, teeth jaw as well. As coverage increases, you do have to compromise on weight and ventilation. Spending more will improve weight and ventilation whatever level of protection you opt for, but you should consider the style of riding you enjoy when choosing a helmet.

If you enjoy cross-country riding with lots of climbing over moderate terrain, you'll want a lighter helmet with more ventilation. Those who focus on fast downhill tracks will want a full-face helmet. There are also varying levels of protection for all-mountain and trail riding in between.

BMX helmets

The no-fuss design of a BMX helmet is built to take a fair bit of abuse on the street and in the park. You tend to crash quite frequently in BMXing - particularly when you start - so BMX helmets are simple and robust to keep the cost down. The classic skate styling is also great for urban riders put off by the sportier aesthetics of road or mountain bike helmets. The robust, low-cost design does, however, come with reduced ventilation.

Kids' bike helmets

Kids’ helmets are held to the same stringent safety regulations as adult helmets so you can be sure that your children are safe. They generally provide similar coverage to mountain bike and BMX helmets, which a bit more coverage at the back of the head. They come in a variety of fun colours and designs to help encourage little cyclists to use them while riding around.

Fitting a cycling helmet

To find your helmet size, you will need to measure your head with a tape measure. Start roughly 1cm above your eyebrows and wrap around your head to find your measurement in cms. Match this to a helmet. Most helmets are sold in a size range, e.g. 58-62cm.

Once you have your helmet, you'll still need to double-check the fit. Everyone's head is a slightly different shape and some helmets will fit better than others.

  • Try the helmet on. Make sure it sits low on your forehead just above your eyebrows.
  • Fasten the chin strap. The straps should fit around the ears in a comfortable V shape that doesn't catch or rub your ears.
  • Fine-tune the fit by adjusting the chin strap and rear dial.
  • Make sure that the chin strap is tight but comfortable. You should not be able to insert more than one finger between the chin strap and the throat but it shouldn't chafe or restrict breathing either.
  • Shake your head from side to side – if correctly adjusted, the helmet should not move

Replacing a helmet

You should replace your helmet immediately after it receives any knocks or bumps, as the protective elements of the foam can be compromised. You don't need to have a high-speed crash for a helmet to break.

BMX helmets are designed to withstand a bit more abuse but should still be replaced after any serious incident.

Even if the helmet is not impacted by a fall, UV rays and moisture can break down the structure of a helmet's protective elements. As such, you should replace your helmet every two years whether you have had a crash or not.