How to Adjust your Bike Helmet


I treated myself to a new bike helmet recently. Don’t worry – I’m not about to start another part of the “war” between those who feel that wearing cycling helmets should be compulsory and those who argue it shouldn’t. Then I noticed a young rider with her helmet angled way back on her head. While I felt that this was an incorrect position, it occurred to me that I had never had any advice on how to wear or adjust a bike helmet – it was just something you put on.

So I thought it might be worthwhile to look and see what information there is out there and found a couple of good guides, one in the USA and one in the UK – which happens to refer to and use a different US guide.

Let’s take the UK information first, which is from the Bicycle Helmet Safety Institute which is a consumer funded body.

First put the helmet on and fasten the buckle. Be sure the front is in front! You want to adjust it to the “Eye-Ear-Mouth” test developed by the Bicycle Coalition of Maine:

• When you look upwards, the front rim should be barely visible to your eye
• The Y of the side straps should meet just below your ear
• The chin strap should be snug against the chin so that when you open your mouth very wide you feel the helmet pull down a little bit.

With the bike helmet in position on your head, adjust the length of the rear straps, then the length of the front straps, to locate the Y fitting where the straps come together just under your ear. That may involve sliding the straps across the top of the helmet to get the length even on both sides. Then adjust the length of the chin strap so it is comfortably snug. If it cuts into the chin and is not comfortable, it is too tight. Now pay attention to the rear stabilizer if the helmet has one. It can keep the helmet from jiggling in normal use and make it feel more stable, but only a well-adjusted strap can keep it on in a crash.

When you think the straps are about right, shake your head around violently. Then put your palm under the front edge and push up and back. Can you move the helmet more than an inch or so from level, exposing your bare forehead? Then you need to tighten the strap in front of your ear, and perhaps loosen the rear strap behind your ear. Again, the two straps should meet just below your ear. Now reach back and grab the back edge. Pull up. Can you move the helmet more than an inch? If so, tighten the rear strap.

For a final check, look in a mirror or look at the wearer whose bike helmet you are fitting. Move the helmet side to side and front to back, watching the skin around the eyebrows. It should move slightly with the helmet. If it does not, the fit pads are probably too thin in front or back.

When you are done, your helmet should be level, feel solid on your head and be comfortable. It should not bump on your glasses (if it does, tighten the nape strap). It should pass the eye-ear-mouth test. You should forget you are wearing it most of the time, just like a seat belt or a good pair of shoes. If it still does not fit that way, keep working with the straps and pads, or try another helmet.

Important Safety Note: with a helmet that fits this well on a child, you must be sure the child removes the helmet before climbing trees and playing on playground equipment. Otherwise there is a risk of catching the helmet and being strangled! That doesn’t happen in normal bike riding, even in crashes, but it can happen while climbing trees or monkey bars.

Finally, you want the straps to stay adjusted. Some helmets – even expensive ones – do not have locking pieces on the side where the straps come together under your ear. If you can move the side buckle with your hand, it will migrate in use. We call that “strap creep,” and it is a major problem. If your helmet has non-locking side pieces, that means you have to either put on a rubber band and snug it up under the side buckle, or you will need to sew the straps when you have the fit just right. If you use heavy thread you only need five or six stitches to hold it. It’s an extra chore, but worth it.

Here’s the second guide, which is from Randy Swart, director of the Bicycle Helmet Safety Institute in Arlington, Virginia, as reported on the US Bicycling magazine site

1. Place the helmet on your head so it’s level front-to-back—when you look up, the front should barely be visible—and not listing to one side.

2. Tighten the strap just enough against your chin so that it pulls your helmet down a bitwhen you open your mouth.

3. The Y of the strap should fall just below each ear.

4. Adjust so that the lid is snug but not too tight. (It shouldn’t move when you shake your head, or leave a mark on your forehead.)

Final Test: Gently push the front of your helmet up and back. If it moves more than an inch, readjust.

If you have diligently read your way though this, you’ll recognise that two of the children in the photo have straps which are far too loose – perhaps that is why big brother is scowling at them!


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