Why helmet fit matters
Before we get into fitting your lid, let’s consider why correct fitment is important. First and foremost, motorcycle helmets are safety devices. In fact, it is one of the most tightly regulated safety devices related to your motorcycle. DOT FMVSS 218 outlines requirements for helmet retention (staying on your head), helmet penetration (stopping things from going through your head), and helmet impact protection (absorbing energy so you don’t get brain damage). All good stuff, right?
Now here’s the kicker: The DOT also regulates helmet size and it makes clear in FMVSS 218 that the above testing is only valid for a properly sized helmet. You read that correctly. If your helmet is out of the size range for your matching headform, all bets are off. Just like an airbag in a car can save the life of an adult passenger, but can be deadly to a small child riding in the front seat, your helmet can only work if it fits properly.
In addition to safety, many of the features designed into your helmet are based around a specific helmet size. Venting, sound insulation and even your viewport design are all based on the expectation that certain parts of your head and face will be in certain places. If the fit is off, you may be disappointed with your helmet.
Steps for fitting a new helmet
So how do we determine a proper helmet fit? Below are the rules for fitting your lid. These rules are geared towards full-face helmets, but the principles can be applied to modular and open-face helmets, as well.
- Start by measuring your head and then select the corresponding helmet size from the manufacturer’s size chart. These sizes are based on DOT-regulated headforms and are the best place to start when fitting your lid.
A new helmet should be snug around any part of your head that would be covered by a baseball cap. This area should be about as firm as a tight knitted winter hat — slightly compressed, but not painful or squeezing.
- There should be no “hot spots” or specific points in the baseball cap area where you feel pressure or pinching. This includes the forehead, back of the head and temples.
- In a new helmet, the sides of your face should be tightly compressed, particularly around your cheeks. The pressure may feel awkward or slightly uncomfortable, but should not be painful. You should not be able to chew gum, and you may not be able to speak clearly.