How to choose your bike helmet

Some cyclists see buying helmets as nothing more than a necessity, while others view it as a chance to invest in style and tech. Whichever kind of rider you are, picking the right helmet is crucial. We spoke to Ulysse Daessle at MET helmets about how – and when – to make the perfect helmet purchase.

road.cc: What’s the first thing that cyclists should consider when choosing their next helmet?

Ulysse Daessle: The way a cyclist should choose their helmet is a very similar process to the way we approach designing a helmet. First, you have to consider for what purpose you are going to use the helmet. What type of riding? What frequency of riding? What level of performance do you require? The casual user or new cyclist requires one type of helmet. The cyclist who rides in the city or who might use e-bikes needs a helmet that offers more head coverage. The Tour de France winner wants aerodynamic performance and ventilation.

Everybody has different needs, and then on top of that, there is a further layer of passion and cycling enjoyment, which can also influence your choice. But as a first step, it’s about choosing the helmet with the best protection for your intended cycling, and choosing the product with the features that will make your life easier and your ride more enjoyable.

Helmet prices range from very little to a lot. Is there a minimum price that you think signifies a suitable quality helmet? 

At MET we start our helmet range at £30 and we go up to £400. At £30 we can deliver a great helmet that features a good fit, a good retaining system, and is comfortable as well as safe. Even at £30, our helmets provide micrometric adjustment, a 360 headband that eliminates pressure points, good ventilation and all the basic features you’d expect. 

In terms of safety, there is no difference between one of our lower-range helmets and one of our more expensive helmets – the way we develop and lab test is exactly the same. And that applies to children’s helmets, Tour de France winners’ helmets and mountain bike full-face helmets. Of course, helmets have different features that make their prices different, but the serious development and safety testing process is exactly the same. 

Is it the case, as with groupsets, where features on top-of-the-range helmets this year might trickle down to more affordable helmets in later years?

With helmets, you can’t take the same features and scale them down because you are speaking about specific moulds and suchlike. However, the more we look into certain technologies, the more able we are to extend them across the range, albeit with some simplifications. 

If there is a key feature that we don’t want to lose – for example, in terms of comfort, the 360 headband would be one – then that is specified across the full range of our open-face helmets. But at the lower end of that range, the technology is a little more basic, whereas at the higher end it features things such as occipital adjustment, vertical adjustment, and ponytail compatibility. Plus, it’s lighter and it’s more refined. 

On the other hand, we are currently creating lights that can be used across all different models and which could be specified across all price points. 

That leads us to our next question: what do buyers get in return for spending more on a helmet? 

If we look at our top-of-the-range open-face road cycling helmet – the Trenta 3K Carbon Mips – and compare it with our entry-level road cycling option – the Idolo – what you get is better aerodynamic performance, lower weight, and a more complex carbon-fibre structure that also allows us to have different air vents in different positions, providing a more effective ventilation system. 

Find out all you need to know about Mips

With more expensive helmets, often the complexity of the structure of the helmet is different, which affects the tooling and therefore the price. And, of course, more expensive helmets may have specific features that are helpful for a particular type of cycling. These features could be things such as visor [peak] – fixed, removable or adjustable; more evolved retention systems; shielding for some urban helmets; or advanced safety technology such as Mips.

What about weight? 

A cycle helmet is a balance between the best safety possible, the best weight possible, the best ventilation possible, the best comfort, and the best aerodynamic performance if that is required. So it’s not necessarily the case that our focus is always to make helmets lighter. 

In fact, there are some psychological factors when it comes to performance helmets. For example, we actually won’t go below a certain weight – 200g – because we understand that athletes don’t feel confident racing with a helmet lighter than that, because their perception is a helmet lighter than 200g wouldn’t be safe. 

So we are not chasing lightweight at all costs, we are looking at weight alongside other considerations – the top of which are safety and performance. These, along with other important features in the helmet design, will have a knock-on effect on weight, but we try to keep overall weight within certain parameters: a mountain bike helmet should weigh 300g to 400g; a road helmet 200g to 300g.

You mentioned Mips technology before. What is this and should helmet buyers look out for it? 

International safety standards for helmets tend to focus on linear, direct, straight-line impacts. However, some years ago, scientists began looking in a slightly different way at how impacts to the head occurred, specifically rotational impacts where the head might be twisted or sliding. They realised that in these cases, the brain would move within the skull, hitting the inside of the skull and creating concussion. 

Mips was one of the first technologies that addressed this problem by having a cradle inside the helmet separate from the external helmet shell, which helps to reduce the rotation speed of the brain inside the skull. This cradle has between 12-15mm of play in every direction, and it absorbs and dissipates the rotational energy which would otherwise be transferred to the head and brain. So Mips is an element that addresses rotational forces, while the helmet itself is made to absorb the linear impact.

When we design a helmet in general, we have to be clever, and at MET we have one of the few machines in the world that can measure rotational impacts. We understand that it also helps to reduce the possibility of rotational forces if we design helmets that don’t have sharp edges or rigid visors – that’s why all our mountain bike helmets have flexible visors.

But we also use Mips because we can see it adds an extra element of safety and we believe it is the best system available to address these rotational forces. And, coming back to the idea of helmet design as a balancing act, Mips is lightweight, it doesn’t affect ventilation, and it is very efficient at doing what it is designed to do.

Now to the really important question: fit. How should somebody buying a new helmet make sure it fits them correctly?

The first thing is to be sure about the size you need. Measure your head and have the measurement in centimetres or inches. Once you have that, you can then go onto helmet manufacturer websites to have a look at different helmet models, or go into your local bike store to look at the range it stocks. 

Really, the best way to make sure you have the right helmet is to try it on. At MET, we really like to work with shops and one of the great benefits they can provide customers with is the opportunity to try things on. However, a lot of websites also allow you to order a helmet and send it back for a different size if it doesn’t fit. 

Are there any easy tips for making sure people buy a helmet that will fit well? 

One thing is to check how the helmet is made. A helmet with a 360 headband and micrometric adjustment will help to eradicate pressure points on your skull: your skull should not be in contact with the helmet shell, it should be in contact with the band. Helmets that offer vertical adjustment and, if possible, occipital adjustment allow you to have the best fit because you can perfectly adjust the way the helmet fits on your head.

Do you see people making any common mistakes when they buy, or even when they wear their helmets?

Yes. We see quite a lot of people wearing their helmets too high, positioned too far back on their head. We advise people to have the helmet positioned horizontally on the head. The helmet also must not be too small, otherwise it will sit on top of the head. If it’s too big it will look like a giant mushroom and you might not be able to tighten it properly, which means there will be stability issues with it on your head. 

Adjustable strap dividers are important too, so you can place the point where the two strap arms meet just underneath your ears – that maximises stability. The straps should be the same length on both sides and well-aligned on the head. 

Essentially, when you have your helmet on your head, it should be stable and it should properly cover your skull. 

When should people replace their helmets? 

Obviously, when you crash you need a new helmet. Even if your helmet drops from table height, we strongly advise you check it. You can often spots signs on the shell or on the internal structure that the helmet has suffered some damage. If you see any indication that the helmet has done its job and dissipated the energy of a fall or crash, then you need to replace it because, if you crash in a similar way again with the same helmet, it won’t perform as intended the second time. 

In terms of long-term helmet replacement where there hasn’t been an incident, that is very tricky for us to recommend as a helmet manufacturer because people think we say it just because we want to sell more helmets. We did some tests internally and we took some helmets that had been stored in optimal conditions for more than 10 years – in the box, away from chemicals and light – and they performed exactly as intended even after that time. The materials themselves won’t degrade as long as there are no external agents acting on them. 

The problem is, as soon as you use the helmet, it is subject to the hazards of cycling: it might fall a couple of times or get knocked or hit branches. Also, you expose it to external elements like the sun and sweat– we did some experiments and found that some people have a more acidic sweat that can damage the helmet over long-term use – so there are all sorts of things that could degrade the helmet’s protection. Also, if you wear it every single day, it will be more exposed to these issues; if you use it once a year then you store it perfectly, the issue is not the same. 

So we can’t say to everybody, ‘You must change your helmet every two years’, but we believe that between three and five years most helmets will be subjected to enough incidents that they won’t perform quite as they should and it would be sensible to replace them. It’s worth remembering that a helmet is a safety device and in the time between changing helmets you probably would have changed your kit or your wheels or your entire bike. Don’t treat your helmet like a flash bit of kit, treat it like a safety device, like your brake pads, and check it regularly. 

If there’s one message we would like to spread it is simply this: check your helmet before every ride to make sure it is in good condition.

For more info on MET's extensive range of helmets, head over to www.met-helmets.com