Finding the Right Bike Helmet Size and Fit

March 27, 2018
Bike Helmet Fit
Ryan SmithTo assure a perfect bike helmet fit, you need to properly adjust the straps around your ears and under your chin.

Protecting your brain should seem like a no-brainer. According to the Federal Highway Administration, bike helmets are 85 to 88 percent effective at preventing head and brain injuries. But “helmets are very similar to seatbelts,” says Erik daSilva, the education and outreach coordinator for the Bicycle Coalition of Maine. A helmet won’t help you in an accident if you aren’t wearing it or if it isn’t adjusted properly. Unfortunately, he says, many cyclists don’t have the right bike helmet size and fit. To make sure you do, follow these tips from daSilva and Doug Smith, a program coordinator at the Washington Area Bicyclist’s Association.

START WITH SIZE
Every helmet varies in shape and in size. To make sure your helmet is the right size for you, put it on and try to move it around. If you can rotate the helmet on your head (too big); if the top of your head is making contact with the inside of the helmet (too small); or if the helmet squeezes the sides of your head (too small), you might need a different size. Once you find the right size helmet, check and see if it has an interior plastic band, which can be adjusted for an even better fit. This band should be tight enough to be comfortably snug. DaSilva’s advice for parents? “Don’t get your kids a helmet that they will grow in to,” he says. “Get them the helmet that is going to fit right then and there.”

THEN FIND YOUR FIT
Smith makes sure students in his adult cycling safety classes have their helmets adjusted before they get onto their bikes. Both he and daSilva recommend an easy-to-remember, three-step, two-finger guide to helmet adjustment.

1) Eyes. The front edge of your helmet should rest two finger widths above your eyebrows. In this position, the helmet is perfectly centered on your head: not so far forward it exposes the back of your head and not so far back it exposes your forehead. If the helmet isn’t comfortable in this position, you might need a different size.

2) Ears. The straps should form a perfect “Y” shape around and below your ears, mirroring a two-fingered peace sign. This will keep the helmet from rolling back or falling forward. The straps should intersect right underneath your earlobes. Most helmets have a sliding buckle on each side; adjust these so they fall just below your ears.

3) Chin. Once you’ve buckled the straps, make sure that you can comfortably fit two fingers between the clip and your chin. According to Smith, if you open your mouth to yawn, you should feel the helmet tugging down on your head, but it shouldn’t choke you. If you can’t achieve a comfortable fit by adjusting the straps, considering trying a different model of helmet.

If you do have an accident, replace your helmet immediately. “Helmets are only allowed one crash,” Smith says. And before you get back on your bike, make sure the new helmet is properly adjusted and in good shape. You never know what lies ahead.


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Katie Hill

Katie Hill is a 2018 graduate of Boston's Emerson College, where she majored in journalism and minored in environmental studies. She interned for AMC Outdoors in spring 2018 and will spend the summer working for a guest ranch in central Wyoming.