How To Fit Your Bike Helmet

A bike helmet can literally save your life if you fall and hit your head during a ride—but it’ll do you way less good (perhaps no good at all) if it doesn’t fit you properly.

Here’s how to get the right size and fit.

Measure your head to find the right helmet size

Helmets are sized according to head circumference. If you’re not sure how large your head is, grab a tape measure and find out.

Measure (in centimetres) right where the helmet will sit on your head, which is the widest part above your eyebrows and ears. Compare your measurement to a helmet sizing chart—though keep in mind that sizes are sometimes called child, youth or adult and other times small, medium or large. 

Because helmets vary in size, shape and design from one manufacturer to the next, try on before you buy. This is especially important if your helmet doesn’t offer a lot of adjustment options (some have fixed strap lengths, for example).

And if you’re buying a helmet for your kid, don’t get them one they’ll “grow into.” Helmets should always fit right now, even if that means you have to size up later.

Adjust the helmet on your head

Your helmet should sit level on your head—not cocked at an angle forward or back or from side to side. If you can fit the width of about two fingers between your eyebrows and the helmet, it’s in the right spot.

Some helmets are fixed in size, meaning they will fit only a specific head circumference. Others are adjustable within a certain range for a more precise fit. If yours is adjustable, turn the rear dial until the helmet sits firmly and comfortably on your head.

Add or adjust the included foam fitting pads to customise the fit even more.

Adjust the side straps

The point where the “V” shape of your helmet straps meets should sit just in front of and below your ears. Move the slider up or down the straps to tighten or loosen the V.

Adjust the chin strap

The buckle on the chin strap should be centered, and when closed, you should be able to fit only a finger or two between the strap and your chin. Tighten or loosen if needed.

Test the fit

The Bicycle Helmet Safety Institute suggests two fit tests:

1. Push the front of your helmet up and back with your palm. If it moves more than an inch, adjust the fit.

2. Shake your head in all directions. If the helmet shifts, adjust the straps.

Finally, make sure the helmet is comfortable to wear. If it isn’t, you’ll feel a constant need to adjust—or you simply won’t wear it at all. And if you do crash and hit your helmet, replace it even if you don’t see any obvious damage.