How should a full face mountain bike helmet fit?
Mountain Biking is an entirely different ball game than regular bike riding. Whether riding on rock-infested terrain or practicing at a mountain bike park, full-face mountain bike helmets provide superior protection compared to regular road bike helmets. It is very important to find a helmet that fits your head perfectly and doesn’t fly off in case of an unfortunate fall or squeeze of your head due to being a tight fit.
How should a full face mountain bike helmet fit:
A correct sized full face helmet should feel snug on your head and shouldn’t move back and forth or side to side when you move your head. One way to test whether a helmet is fitting you right is when you put the helmet on its front should be no more than an inch above your eyebrows. If the front of the helmet is sitting too high from your eyebrows, the helmet is probably small for your size. Similarly, if the helmet’s front is sitting below your eyebrows, the helmet is too big for you.

But selecting the right fitting helmet is a bit more complicated than putting it on and wiggling your head to see if it moves around. There are many other factors you need to consider when getting a full-face helmet, and in this article, we will tell you how you can get a mountain bike helmet that fits your needs and your head size perfectly, so read on.
Contents
Know the size of your head before going helmet shopping
One of the most common reasons full-face helmets don’t fit is that people buy them without knowing the correct-sized helmet. So before you go shopping for your helmet, find your head’s measurement with the help of either a measuring tape or a string by wrapping it around your lower forehead. Don’t wrap the measuring tape too tightly around your head, and make sure the tape is flexible and not rigid. For a more accurate reading, take help from a friend or family member to measure your head size. Knowing the size of your head will also increase your purchasing options, as you can buy your helmet online if you are more comfortable with shopping online.
Standard helmet sizes you will find for different head measurements are as follows:
- Small: Small-sized full-face helmets are ideal for people with a head diameter between 20 to 21.75 inches.
- Medium: Medium-sized full-face helmets are for people with a head diameter between 21.75 to 23.25 inches.
- Large: Large-sized full-face helmets are for people with a head diameter of 23.5 to 24.75 inches.
Apart from these standard sizes, there is a one size fits all option for men, women, and children. But the most common complaint about one size fits all helmets is that they are not a proper fit, and they need to be tightened around your head for them actually to stay on, which can get a little uncomfortable.
How to make a full-face helmet fit better?
If you are in between sizes and standard small, medium, and large-size full-face helmets aren’t fitting you properly, you can always buy inner liner pads that suit your head and face. Most full-face helmets don’t have a rear retention system to hold the helmet in place; instead, they have pads on the inside that allow the helmet to stay snug on your head so that they don’t move around while riding. Here are some ways you can use these pads to improve how your helmet fits you.
- Try pads with different widths: You can easily buy liner pads with different thicknesses for your full-face helmet, allowing you to choose how your helmet fits you. If your helmet feels too tight, you can get replacement pads that are less thick than the stock ones so they can fit your head perfectly. Similarly, for a helmet that moves around on your head or falls forward when looking straight ahead and obstructs your vision, you can find thicker pads to help you find a better one.
- Wear cycling headwear under your helmet: If you don’t want to spend money on a new set of pads after you have already spent on a full-face helmet, then this DYI method might help. Grab a cycling cap or a similar headwear and wear it under your full-face helmet if it does not fit snuggly on your head. The added layer under the helmet will serve as additional padding to fill the space in your helmet and make it fit perfectly.
- Adjust your helmet’s chin strap: The easiest way to adjust your chin strap is by doing a simple test to see if the chin is adjusted properly. Try opening your mouth with your chin strap secured, and as you open your mouth, the helmet should press against your head a little bit. If you can open your mouth too wide without the helmet pressing against your head, then your chin strap is adjusted too wide, and it can cause the helmet to fly off your head in case of a fall.
Types of full-face mountain bike helmets
Innovation has made its way into full-face mountain bike helmets, and you can choose from plenty of options to fit your needs. But remember that every variation of full-face helmets is meant to fit a specific scenario.
● Enduro Helmets
Generally, full-face helmets become very hot and difficult to breathe in, but enduro-style full-face helmets are a lightweight and well-ventilated variation of full-face helmets. Although Enduro helmets are strong and keep the head well protected in case of a minor crash but being lightweight, they are not suitable for hardcore downhill mountain biking and should only be used by enduro racers.
● Two in one helmet
These types of helmets can be converted into half-shell helmets or full-faced downhill helmets thanks to the removable chin of the helmet, and this feature makes them a good choice for people who want a helmet that can be used for road riding as well as mountain biking. But then again, these convertible helmets aren’t as sturdy as dedicated full-face helmets, so they should only be used for casual downhill riding. These helmets were very popular in the late ’90s and early 2000s, but they slowly lost their popularity now, they are making a comeback with better materials, and their target market is mostly enduro riders.

● Downhill helmets
If you are an adrenalin junky and like to do aggressive downhill runs and enduro riding, then it is best to go with downhill mountain bike helmets designed for this specific purpose. Downhill full-face mountain bike helmets provide the highest level of protection to the rider in case of an unfortunate high-speed crash. These helmets are meant to be worn with goggles for added protection for high-speed downhill runs.
Pros and cons of full-face mountain bike helmets?
● Pros of full-face helmets
- Whole face: A full-face helmet protects your whole face and head, making it the safest option.
- Gives confidence: If you are a conscious rider with confidence issues, then a full-face helmet can give you the feeling of confidence you need to improve your skills.
- Goggles: Most full-face helmets come with goggles that help you to protect your eyes from debris or bugs when riding.
- Warm: They are great for hitting the trail during cold weather, keeping the head nice and warm.
● Cons of full-face helmets
- More expensive: They are not the cheapest option if you want an affordable helmet.
- Heavier: They are usually heavier than open-face helmets; therefore, it takes some time to get used to wearing a full-face helmet.
- Ventilation: Full-face helmets aren’t very well-ventilated and pose an issue of not being able to evaporate sweat efficiently when wearing one.
- Hot in summer: If you do a lot of paddling in summer, it can get extremely hot in full-faced helmets.
- Confidence: Riders tend to get a bit too confident after wearing full-face helmets and go for trails or jumps they usually wouldn’t and end up getting hurt. So as long as you know your limits and skill level, you should be fine.
Do you need a full-face helmet?
The bottom line is if you like to go on trails or are into some jumps, you are always at risk of injury. While it is true that more weight and lack of ventilation in full-face helmets need some getting used to, it is a small price to pay for complete head and face protection.
How do I measure a Full Face Helmet?
There are five steps I recommend following when you want find your perfect full face helmet:
Step 1: Measure your head
The first step you should always do is measure your head. Use a flexible tape measure and wrap it around your head an inch and a half above your eyebrows. Look to the horizon and ensure the tape measure is horizontal. This should give you the diameter of your head. You can also use a piece of thin rope to do this and use a tape measure to measure the length.
With this diameter, you can now check the sizing chart from various helmets and find one that matches your head. If you find your size in the middle, I recommend choosing the lower size. This should give a good fit for most. Now you can order the helmet.
Step 2: Try the helmet
Knowing the helmet should fit, it is time to try it on. Put it on and fasten the chin strap. The first couple of times, putting the helmet on will take a little bit more effort, as all the material is still new and has not been set to your head.
The helmet shouldn’t really move around when you move your head around. You can also try grabbing your helmet in your hands and trying to move it around. A small movement is fine, but it is not a good fit when you can move it around.
Step 3: Check the chin bar
The next step you need to do is to check the position of the chin bar. The chin bar should cover your chin completely and your mouth slightly. You can move the helmet slightly up or down by grabbing the chin bar. Ensure the chin bar is in the correct position before continuing to step 4.
Step 4: Check the visibility
With the chin bar in the correct position, check that you have good visibility. Your view should not be obstructed greatly by the helmet. A little bit of helmet in the far ends of your view is fine.
Step 5: Overall feeling
Knowing the position and view of the helmet is fine, check if wearing the helmet feels ok. Each person has a slightly different head shape, and a specific helmet can be a perfect fit for one and feel bad for somebody else. If you feel that certain parts put more pressure on your head, and in other locations, you do not feel it, it indicates that it is not a great fit for you.
Some helmets come with a replaceable neck roll or cheap pads. This can be a great way to make it fit well. I have had several occasions where a helmet did not fit well or didn’t feel great. In those situations, return the helmet and try another one.
How tight should a full-face helmet be?
A full-face helmet should be such that if you shake your head around, it should only move slightly and not wobble. Similar if you use your hands to move the helmet. But it should always feel relatively comfortable and not be so tight it hurts.
If the helmet is still new, it will bed a little. But do not expect a supertight helmet to be loose after a while. Also, the padding around the neck will compress after wearing it for some time.
Several helmets also have different cheek pads or replaceable neck rolls. Try them to see if that helps.