How to choose and properly fit a bike helmet

How do you know if your child's helmet fits properly? Is there a shelf life for helmets? Are helmets with spikes safe? The experts at the UW Health Kids Safety Center offer these tips for proper protection:

How to make sure your child's bike helmet fits

Step 1: Position

A bike helmet should fit snugly and sit level on your child's head and low on the forehead. A good test is to place one or two fingers above your child's eyebrow. There shouldn't be a gap between the fingers and the bottom of the helmet.

"You often see kids wearing the helmets much too high on the forehead," said Safety Center child safety educator Sherri Faust. "The brain is what we're trying to protect by wearing the helmet — which means covering the forehead."

Most bike crashes occur when the body flips over the handlebars, so the forehead typically bears the brunt of the impact, Faust said. "If the helmet's all the way up high so you don't mess up your hair, you're not protecting your brain," she said. If the helmet sits too high on the head and will not cover the forehead, some helmets have a turn dial adjustment to allow the helmet to sit lower, just above the eyebrows. Or, a larger helmet might be needed.

Step 2: Side straps

Adjust the slider to form a "V" shape under and slightly in front of the child's ear.

"Making the 'V' helps ensure the helmet fits comfortably around the ears," Faust said. "If the strap is bothering your child or rubbing against their ears, they're not going to want to wear it."

Try to make the front strap slightly shorter than the back strap, if the helmet's straps are adjustable, Faust said. That will help keep the helmet in place, level to the ground — and therefore offer the best protection.

Step 3: Chin strap

Buckle and tighten the strap until it is snug, so that only one finger fits under the strap.

"That's probably the biggest thing: If it's too loose, the helmet isn't going to stay where it needs to stay if there's an accident," Faust said. "The same is true for adults. It'll feel kind of tight, but that's how it's supposed to feel."

Step 4: Test for proper fit

Have your child open their mouth wide and make a big yawn. "They should be able to feel the helmet pulling down" Faust said. If the helmet slides back easily:

• Unbuckle it and shorten the front side strap.

• Buckle, re-tighten the chin strap and test again.

• Finally, be sure any extra chin strap is secured by feeding it through the rubber band (if the helmet has one), and then roll the rubber band down to the buckle.

What should you look for in a helmet?

Padding

Adjustability is a big factor in extending the helmet's useful life, Faust said. Look for a helmet with extra pads, so you can adjust the padding as your child grows.

Avoid spikes

While your child might think spikes or a "mohawk" on a bike helmet looks cool, Faust advises against buying a helmet with these and other types of 3-dimensional decorations (e.g., horns, ears, etc.). "You really do want a relatively smooth helmet surface," she said. "If you fall off your bike and your helmet has spikes, those are going to dig into the ground, which is going to torque the neck. And now you've got the chance of creating more injuries. A smooth helmet will just glide," offering optimal protection. Instead of spikes, Faust suggest adding decals or stickers to a smooth bike helmet so a child can make it his or her own.

Multisport helmets

If your child is riding a scooter, skateboarding or roller blading, a helmet should be worn that's specifically designed for that activity and the type of crash that typically occurs with it, Faust said.

When should a helmet be replaced?

In addition to replacing a helmet as a child head grows, it's also important to replace helmets that have been worn in a crash, Faust said. Even if damage isn't visible, impact crushes the helmet's foam, which is what protects the brain.

"Once the foam compresses, it's not going to be able to absorb another crash or bump as readily as it did in the beginning," Faust said.

If you're not sure whether the foam was affected, it's safest just to replace it. That's also why you should be careful with your helmet — so you don't damage the protective foam by dropping it. "When you're done with it, take it off gently," she said. "Don't just throw it to the ground or toss it on the driveway."

Bike and multisport helmets for children and adults are available at the UW Health Kids Safety Center at American Family Children's Hospital, most for $10. Safety Center staff can also help with making sure helmets fit properly — whether you purchase it at the Safety Center or elsewhere. Safety Center hours and more information