What is the best way to measure your head for a bike helmet? The best way to measure your head for a bike helmet is with a flexible measuring tape, ensuring it’s snug but not tight, and noting the measurement in centimeters.
Getting the right bike helmet fit is crucial for safety and comfort. A helmet that’s too loose can shift and fail to protect you in a crash, while one that’s too tight can cause headaches and discomfort, discouraging you from wearing it at all. This guide will walk you through exactly how to measure your head size to ensure you find the correct helmet size. We’ll cover everything from the tools you’ll need to interpreting the results and what to do if your measurements are between sizes.
Why Accurate Head Measurement Matters for Bike Helmets
When you’re out on your bike, your helmet is your most important piece of safety gear. It’s designed to absorb impact and protect your brain from serious injury. However, its effectiveness relies entirely on a proper fit. A helmet that doesn’t fit correctly cannot do its job. This is why measuring head size accurately is the first and most critical step in finding helmet size.
The Importance of Head Circumference
The primary measurement for helmet sizing is your head circumference. This is the distance around the widest part of your head. Most helmet manufacturers base their sizing on this measurement, often providing a helmet size guide with ranges in centimeters.
Safety First: The Helmet’s Role
A well-fitting helmet stays put, even during sudden movements or impacts. It covers your forehead adequately and doesn’t wobble or slide. This ensures that the helmet’s protective shell and impact-absorbing liner are positioned correctly over your skull, ready to absorb the forces of a potential accident.
Comfort Enhances Usage
Beyond safety, a comfortable helmet makes you more likely to wear it every time you ride. If a helmet feels too tight, too loose, or causes pressure points, you’ll probably be tempted to skip it, especially on shorter rides. A proper bike helmet fit means you can focus on your ride, not on adjusting an uncomfortable helmet.
Tools Needed for Measuring Your Head
You don’t need specialized equipment to get this essential measurement. Here’s what you’ll need:
- A flexible measuring tape: A tailor’s tape measure is ideal. If you don’t have one, you can use a piece of string or a shoelace and then measure that against a ruler or rigid measuring tape.
- A mirror: This helps you ensure the tape is positioned correctly around your head.
- A pen and paper: To record your measurement.
Step-by-Step Guide to Measuring Your Head
Follow these simple steps to get an accurate head measurement for your bike helmet.
Step 1: Locate the Widest Part of Your Head
The widest part of your head is typically about an inch (or two fingers’ width) above your eyebrows and ears. It’s usually a bit higher than where a typical hat would sit.
Step 2: Position the Measuring Tape
- Start at the front: Place the end of the measuring tape on your forehead, just above your eyebrows.
- Wrap around: Bring the tape around the back of your head, going over the most prominent part of the back of your skull. This is usually the widest point.
- Meet at the front: Bring the tape back to where you started, on your forehead.
- Ensure snugness: The tape should be snug but not uncomfortably tight. It should feel like a comfortable headband.
- Keep it level: Make sure the tape measure is parallel to the ground all the way around your head. Avoid tilting it up or down.
- Use a mirror: If possible, use a mirror to check that the tape is level and positioned at the widest part of your head.
Step 3: Read and Record Your Measurement
Once the tape is in place and snug, read the measurement where the tape overlaps. This number will likely be in centimeters (cm) or inches. Most helmet sizing charts use centimeters, so it’s best to get your measurement in that unit. Write down this number. This is your head circumference.
Step 4: Double-Check Your Measurement
It’s always a good idea to repeat the measurement a couple of times to ensure accuracy. Different positions or slight variations in tape tension can lead to different readings. Aim for consistency. This is crucial for how to measure for a helmet accurately.
Interpreting Your Head Measurement for Helmet Sizing
Once you have your head measurement guide data, you can start looking for helmets.
Comparing to Manufacturer Sizing Charts
Every helmet brand will have its own helmet size guide. These guides will typically list size ranges (e.g., Small: 51-55 cm, Medium: 55-59 cm, Large: 59-63 cm).
- Find the right size: Locate the size that best matches your measured head circumference.
- Consider overlaps: If your measurement falls exactly on the border between two sizes, it’s usually best to try both. Some brands might be cut slightly differently, so one might offer a better fit.
Understanding Hat Size vs. Helmet Size
It’s important to note that your hat size chart measurement might differ slightly from your helmet measurement. Hats sit on the outside of your head and can be adjusted, whereas a helmet needs to fit snugly on the bone structure of your skull. While hat size can give you a rough idea, always rely on your direct head measurement for finding helmet size.
What to Do If Your Measurement is Between Sizes
This is a common scenario, and it’s where trying on helmets becomes essential.
Trying On is Key
If your head circumference falls between sizes on a manufacturer’s chart:
- Try the smaller size: Check if it fits snugly without feeling restrictive or causing pressure points.
- Try the larger size: See if it feels secure but also if it’s too loose or leaves too much room for adjustment.
- Consider adjustability: Many modern helmets have adjustable dial systems at the back. This can often help fine-tune the fit, especially if you’re between sizes. A helmet with an adjustable fit system might make the larger size work better if it can be tightened sufficiently.
The Importance of the “Snug” Test
When trying on helmets, look for the following signs of a correct helmet size:
- No significant gaps: The helmet should feel like it’s conforming to your head’s shape. There shouldn’t be large air gaps between your head and the helmet’s padding.
- No pressure points: You shouldn’t feel uncomfortable pinching or pressure on any part of your head.
- Even distribution of pressure: The weight of the helmet should feel distributed evenly across your head.
How to Check for a Proper Bike Helmet Fit (Beyond Just Measuring)
Even with the correct measurement, a final fitting is essential. This is where you confirm your bike helmet fit.
The Shake Test
- Buckle the chin strap: Fasten the buckle securely.
- Tighten the retention system: Use the dial or other adjustment mechanism to snug the helmet around your head.
- Nod your head: Gently shake your head from side to side and nod up and down. The helmet should stay in place and not shift significantly. If it moves a lot, it’s too big or not adjusted properly.
The Brow Test
- Position correctly: The front edge of the helmet should sit about one to two finger-widths above your eyebrows. This ensures your forehead is protected.
- Check for visibility: The helmet shouldn’t obstruct your vision. If it sits too low and blocks your line of sight, it’s not fitted correctly.
The Strap Adjustment
- “V” shape around ears: The side straps should form a “V” shape just below your earlobes. Adjust the sliders to achieve this.
- Chin strap snugness: The chin strap should be snug enough that you can only fit one or two fingers between the strap and your chin. It should not be uncomfortably tight or restrict breathing.
Foam Padding and Fit Systems
Many helmets come with different thicknesses of foam padding. These can be swapped out to fine-tune the fit, especially if you have an odd head shape. The rear adjustment dial (often called a “fit system” or “retention system”) is crucial for tightening or loosening the helmet to achieve that perfect snugness.
Common Mistakes to Avoid When Measuring Your Head
To ensure you get the most accurate measurement possible, be mindful of these common pitfalls:
Ignoring the Widest Part
Focusing on where you normally wear a hat rather than the actual widest circumference of your head can lead to an incorrect measurement. Always go slightly higher and around the fullest part.
Measuring Too Tightly or Too Loosely
A tape measure that’s pulled too tight will give you a smaller measurement than reality, potentially leading you to buy a helmet that’s too small. Conversely, a loose measurement can result in a helmet that’s too big. Aim for the feel of a comfortable headband.
Not Repeating the Measurement
Humans aren’t perfect measuring instruments. Repeating the measurement a couple of times helps catch any errors and ensures consistency.
Relying Solely on Hat Size
As mentioned, hat size chart information is a starting point at best. Direct head measurement is paramount for proper helmet sizing.
Forgetting About Hair and Hair Accessories
If you frequently ride with a bandana, thin skullcap, or other hair accessories, consider measuring your head with them on, or at least factor in the extra space they will take up. A helmet that fits perfectly without anything underneath might be too tight with a skullcap.
Helmet Sizing Chart Example
Here is a sample helmet size guide. Always refer to the specific manufacturer’s chart for the helmet you are interested in.
| Size | Head Circumference (cm) | Head Circumference (in) | Typical Hat Size (US) |
|---|---|---|---|
| XS | 48 – 53 | 18.9 – 20.9 | 6 – 6 5/8 |
| Small | 53 – 57 | 20.9 – 22.4 | 6 5/8 – 7 1/8 |
| Medium | 57 – 61 | 22.4 – 24.0 | 7 1/8 – 7 5/8 |
| Large | 61 – 65 | 24.0 – 25.6 | 7 5/8 – 8 1/8 |
| XL | 65 – 69 | 25.6 – 27.2 | 8 1/8 – 8 5/8 |
Note: These are approximate. Different brands and models will have variations.
What If My Head Shape is Unusual?
Some people have heads that are not perfectly round. They might be more oval or have prominent brow ridges.
Oval vs. Round Heads
- Oval-shaped heads: Some helmet models are designed with a more oval fit. If you find round helmets pinch the sides of your head or feel too loose at the front and back, look for helmets that specify an “oval” fit.
- Brow ridge: If you have a prominent brow ridge, ensure the helmet sits comfortably without pressing down on your brow.
Trying On is Your Best Friend
For unusual head shapes, trying on multiple brands and models is the only way to guarantee a good fit. What works perfectly for one person might not work for another, even with the same head circumference.
Maintaining Your Helmet for Optimal Fit and Safety
Once you’ve found the correct helmet size, proper care will ensure it continues to provide a good fit and maximum protection.
Cleaning Your Helmet
Regularly clean the shell and interior padding with mild soap and water. Avoid harsh chemicals, as they can degrade the helmet’s materials. Follow the manufacturer’s cleaning instructions.
Checking for Damage
Inspect your helmet regularly for any signs of damage, such as cracks, dents, or deep scratches. If your helmet has been in a crash, even if there’s no visible damage, it should be replaced, as the impact-absorbing foam may have been compressed.
Replacing Your Helmet
Helmets have a lifespan, typically around 3-5 years from the date of manufacture, even if they haven’t been in a crash. The materials can degrade over time due to exposure to sunlight, sweat, and temperature changes. Always check the manufacturer’s recommended replacement schedule.
Frequently Asked Questions (FAQ)
Q1: Can I use a tape measure from my kitchen?
A1: While any flexible measuring tape will work, a tailor’s tape measure is best as it’s designed for curves. If using a rigid ruler, you’ll need a piece of string or a shoelace to wrap around your head and then measure against the ruler.
Q2: How do I know if a helmet is too tight?
A2: A helmet that is too tight will cause noticeable pressure points or headaches, especially after wearing it for a short period. It might also feel difficult to put on or take off.
Q3: What if my hair is very thick or bulky?
A3: If you wear your hair in a style that adds significant volume, it’s a good idea to measure your head with your hair styled as you would wear it for riding. You might need to size up or look for helmets with more internal volume.
Q4: Do cycling caps or skullcaps affect helmet fit?
A4: Yes, they can add a millimeter or two to your head circumference. If you plan to wear a cycling cap or skullcap regularly, it’s best to measure your head with it on to ensure your helmet will still fit comfortably.
Q5: How many times should I measure my head to be sure?
A5: Repeating the measurement at least twice, ensuring the tape is level and snug each time, is recommended to confirm accuracy.
Q6: Can I use my old hat size to buy a new helmet?
A6: While your hat size can give you a general idea, it’s not precise enough for buying a bike helmet. Always measure your head circumference directly for helmet sizing.
Q7: What does “retention system” mean on a helmet?
A7: The retention system is the adjustable mechanism at the back of the helmet that helps secure it to your head. This is often a dial you turn to tighten or loosen the internal band.
Q8: Should I buy a helmet online if I can’t try it on?
A8: It’s always best to try on helmets in person to ensure a proper bike helmet fit. If buying online is your only option, make sure the retailer has a good return policy in case the fit isn’t right. Carefully consult the brand’s specific helmet size guide.
By following this comprehensive head measurement guide, you can confidently choose a bike helmet that offers optimal safety and comfort for all your rides. Remember, a proper fit is the foundation of a safe cycling experience.