May 7, 2022
Cedar Cycling

Bike Helmet Fit And Size Guide

Bike helmets are an essential piece of kit for any cyclist, but choosing the right helmet is not just a matter of looking for one that looks good.
First and foremost, a bicycle helmet has to do its job, and this means protecting the rider in the event of a crash. But a helmet should also be comfortable and offer good ventilation, so that you don't overheat.

There are a few simple things to look out for when buying a cycle helmet to make sure you get the best possible helmet:

  • The outer shell should be made from expanded polystyrene (EPS) which is designed to absorb energy and disperse the energy of a crash over a large area, reducing the risk of serious injury.
  • There should be plenty of vents to keep your head cool on hot days, but also to help with airflow in colder weather.
  • The straps should be adjustable and easy to use.
  • The helmet should fit properly - not too tight, or too lose - and sit level on your head.
  • The helmet should come with plenty of information about safety and care.

Helmet Fit Guide

Helmet Fit Guide

Step 1

Place the tape measurer about 25 mm above your eyebrows.

Step 2

Ensure the measuring tape is about 15 mm above your ear.

Helmets come in a variety of sizes - usually small, medium and large. Before you buy a helmet, you need to measure your head size. You can do this by measuring around your head just above your eyebrows where your helmet will sit.

Next, check that the helmet you are thinking of buying has the correct 'size range' as listed in the product description. Different brands have different size ranges so it is important that you check this before you buy a new helmet.

Knowing what size helmet you need is not just important for comfort; it's also important for safety. If a helmet is too big it could move around when you're riding or fall off in an accident, leaving your head unprotected. On the other hand if a cycle helmet is too small this could restrict blood flow or even cause injury if it's too tight to stay on properly during an impact with the ground or other obstacles.

In order to ensure that your cycle helmet fits correctly it's best to go into a store where you can try on several different sizes before making your decision - this is especially important for children as their heads grow at different rates and they may have outgrown their current helmet before they need to replace it.

Helmet Size Guide

Helmet Size Guide

Here is a list of common head measurements in centimetres (cm) together with the corresponding helmets size:

Adult Helmet

Adult Helmets
WesternS51-55 CM
WesternM55-59 CM
WesternL59-63 CM
AsianS51-57 CM
AsianM55-61 CM
AsianL59-65 CM

Youth Helmet

Adult Helmet
WesternOSFM49-57 CM
AsianOSFM51-59 CM

Child Helmet/Toddler Helmet

Child Helmet
UniversalChild Universal50-55 CM4-10
Child Helmet
UniversalToddler Universal46-51 CMUnder 5
Toddler Helmet


We hope that the guide has been useful. If you have any further questions about choosing the correct size helmet, or need advice on fitting your helmet properly, please don't hesitate to ask us.

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