Bike helmet sizes explained: how to measure your bike helmet size for a perfect fit

Ensuring your bike helmet fits properly is crucial for maximum protection. A loose helmet might not stay put during an accident, increasing the risk of a dangerous head injury. On the flip side, a too-tight helmet is not only uncomfortable but also potentially unsafe.

 

Let's walk through sizing for both road bike and mountain bike helmets, considering the variations in size notations among different manufacturers.

 

While some budget helmets claim a universal fit, many helmets come in specific sizes for a secure and comfy feel. Manufacturers use different methods – some provide head diameter ranges (like 52 to 56cm), while others stick to small/medium/large categories. If sizes are in words rather than numbers, you'll find a link to a sizing chart that breaks down the diameter range for each size.

 

Remember, each brand might have specific size guides for different helmet models, so always double-check before making a purchase.

 

Most bike helmets, excluding some specialized models, have an adjustable cradle to accommodate various head sizes within a defined range. However, heads aren't all the same shape, and helmets can differ in shape across brands. Just like with cycling shoes, it's wise to try before you buy to nail the perfect fit.

 

Now, let's measure your head for that ideal helmet size. When buying a new helmet, use a flexible fabric tape measure. Measure just above your eyebrows and ears – this is where the helmet should sit for a proper fit. Pro tip: Raid that sewing kit in a biscuit tin; there's likely a tape measure hiding in there.

 

Helmet Fit 101: Getting It Right

 

Ensuring your helmet fits correctly is crucial for both comfort and safety. Forget about the metal tape measure from your toolbox – it's not your go-to for measuring the curves of your head. Opt for string if you don't have a proper measuring tool, and remember, the fit should be snug, not suffocating.

 

Adjusting the Fit

 

Once you've measured accurately, fitting the helmet should be a breeze. Place it on your head, ensuring it sits comfortably above your eyebrows and ears. Use the rear dial to adjust the cradle – it might tighten the cradle or a band around the helmet's circumference. Fine-tune the cradle's height for that perfect fit. The chin strap? Snug, not too tight.

 

Replaceable Padding

 

Some helmets offer replaceable padding for a customizable fit. Don't be discouraged if it takes a few tries to get it spot-on. The end goal is a snug fit; the helmet shouldn't rotate and should stay level on your head.

 

MIPS Technology

 

Ever wondered about MIPS? Modern helmets often feature MIPS liners, enhancing safety by allowing the outer shell to rotate independently. No need to worry about sizing adjustments – MIPS is now integrated into the helmet's design from the get-go. A slight movement (around 10 to 15mm) is normal and confined to the outer shell, not the cradle.

 

Styling Concerns

 

Ponytails and helmets don't always get along. Some helmets cater to this hairstyle with a rear exit port, while others don't. Adjust your hair or choose a helmet designed to accommodate your ponytail. Thin hats or cycling caps are fine under helmets, but beanies or hoods? Not recommended – they alter the fit and compromise safety.

Follow these tips for a helmet fit that's snug, safe, and tailored to your style.