What is the difference between a mountain bike and a road helmet?
Road helmets usually don’t have a visor, are sleeker, more compact, and have more & larger air vents compared to the heavier, rounder, bulkier and airflow restricted mountain bike helmet.
However, the real question might be what helmet offers better protection?
The latest finding from the STAR protocol finds that road cycling helmets offer more and better safety protection (including protection from concussions), compared to MTB trail riding/non-road helmet. Also, helmets with MIPS (or similar technology) perform better than helmets without.
The classic road helmet
Mountain bike helmet
bicycle helmet standards & linear acceleration
All bicycle helmets in the U.S. market must meet the Consumer Product Safety Commission (CPSC) standards. Europe also has standards, the European Standard
(EN1078), which are 20% more stringent than in the United States. Both of these countries' mandates operate on a pass-fail system and if you bought a helmet in the U.S. or Europe then your helmet passed the required tests.
However, both the CPSC and Europe Standards only test the helmet for peak linear acceleration (PLA) through a series of drop tests on the top of the helmet. No tests are performed that check angular or rotational acceleration. However, in the real world linear type of falls are extremely rare.
So what does linear acceleration look like in the real-world?
Imagine that you are cruising down a trail and all of a sudden you fall off your bike and start flying through the air, then you magically stop all your forward momentum until you're suspended in midair with your body perfectly aligned straight up and down, and at this point, you crash headfirst into the ground.... from a height of about 7 feet (2 m)…….like I said………rare.
Most real-world falls and accidents happen at angles, such as:
Going over the handlebars and landing on the back of your head
Headfirst dive from hard braking
Side-fall from stalling-out with clipless pedals
Washout
Skidding sideways
Picture A = Standard bicycle helmet test
“Drop tester setups. (a) Normal impact setup, as specified by CPSC bicycle helmet testing standard. (b) Oblique impact setup, with angled anvil, Hybrid III biofidelic neck, and 3-axis load cell.” (Image Source & Quote: (Hansen et al.)
MTB vs road helmets & protection
Researchers at Virginia Tech created the STAR protocol for testing impacts that are more realistic in the real-world. The STAR method is a “biomechanically-based helmet evaluation protocol that quantifies the ability of individual helmet models to reduce the incidence of concussion.”
A 2019 study in the Annals of Biomedical Engineering tested 30 helmets using the STAR protocol and found that ROAD helmets tested BETTER than MTB trail/commuter helmets. Also, lids with MIPS (Multi-directional Impact Protection System) performed better than helmets without the MIPS slip-plane layer. MIPS technology helps reduce rotational forces, which are forces that are commonly associated with concussion type injuries.
Road cycling helmet
Road Cycling helmet
Road cycling helmets are designed to be:
Lightweight
More aerodynamic
Better ventilated with more and bigger vents
More compact
Trail riding helmet
mtb helmets
Mountain bike helmets are designed with:
Greater head coverage, particularly on the sides and the back
Smaller & fewer vent - designed so trail objects don’t puncture through during fall
Different vent placement
Heavier
Thicker and stiffer outer shell
Adjustable visor
Why did road helmets perform better than trail helmets?
Why did the road helmets with less coverage perform better than the heavier XC-MTB style lids?
“with non-road style helmets among the worst”
The sample size is obviously small, with only 30 helmets tested in the aforementioned study. However, Dr. Megan Bland in her doctoral dissertation, Assessing the Efficacy of Bicycle Helmets in Reducing Risk of Head Injury also noted that “helmets that performed worse in one impact configuration tended to perform worse in others, with non-road style helmets among the worst.”
So what is the reason for non-road style helmets performing worse in tests that mimic real-world bicycle accidents?
Dr. Bland’s 223-page dissertation found that the heaviest and stiffest helmets regardless of style performed the worst. Bland suggests that shell thickness, vent configuration & radius of curvature influenced the “helmet effective stiffness.” Basically, helmets that are lighter, more ventilated with strategically placed vents perform the best because the less-rigid helmets do a better job of cracking the polycarbonate (or similar material) shell and spreading the initial burst across the whole surface before compressing the foam liner.
Do bicycle helmets prevent concussions?
“No helmet design has been proven to prevent concussions. The materials that are used in most of today’s helmets are engineered to absorb the high impact energies that can produce skull fractures and severe brain injuries.”
Do mountain bike or road helmets prevent concussions?
No, according to the U.S. Consumer Product Safety Commission:
“No helmet design has been proven to prevent concussions. The materials that are used in most of today’s helmets are engineered to absorb the high impact energies that can produce skull fractures and severe brain injuries.”
CPSC Standards & Concussions
The CPSC standards were created back in 1994 when doctors didn’t understand much about concussions, and the standards haven’t really changed much since.
Helmet manufacturers still have to pass tests designed to prevent skull fractures in order to sell them in stores. However, as concussions have been brought to national attention, bicycle helmet manufactures have created their own tests and technology (Koroyd & MIPS for example) to offer a level of protection against brain trauma that is currently not part of the governmental testing protocol. So the answer to this question is really more of a yes…but trying to quantify the answer is difficult.
Full face MTB helmet
mtb vs road & what helmet manufactures say
I contacted several large bicycle helmet manufactures to find out what the differences are between road and mountain bike lids, and here are some of the responses:
“Road helmets are much lighter but will have the same amount of impact protection as mountain bike helmets”
“Helmet construction between road and mountain bike helmets will be identical. That is, they will meet all the same safety standards.”
“The main differences will be shape. Generally the mountain bike helmets will have a bit more protection around the lower portion of the back of the head”
“Road helmets are much lighter but will have the same amount of impact protection as mountain bike helmets” - Specialized Bicycle Components, Inc.
“Road helmets will rarely have a visor where as mountain bike helmets will have this feature standard”
“Most of our XC mtb racers will use road helmets because they are lighter and cooler”
DO CONVENTIONAL BICYCLE HELMETS PROVIDE ADEQUATE PROTECTION IN MOUNTAIN BIKING?
Do conventional bicycle helmets provide adequate protection in mountain biking was the name of an article that was published in Wilderness & Environmental Medicine way back in 1995, when mountain bikes were commonly called ATB or all-terrain bicycles.
Back in the ATB days, there was no such thing as specific MTB helmets. Today, even though bike shops have entire lines of off-road helmets, it’s really more superficial since all helmets have an identical construction. Outside of a few cosmetic and stylish modifications, no real differences exist, and the few differences that do, such as less ventilation, extra weight, and stiffer shells might actually do more harm than good.
bicycle Helmets & the future
Today’s bicycle helmets are vastly superior to those of even a handful of years ago. New and improved technology doesn’t just apply to the bikes, but all the gear, including the most essential piece of protective equipment……the helmet.
Many modern bicycle helmets come equipped with a slip-plane layer, different foams, and foam densities, with the traditional EPS being replaced with thicker densities or different foams altogether. Koroyd, WaveCell, and MIPS among others, make the helmets more protective which equates to a safer and more fun bicycling experience.
Cross-sectional images of helmets without a rotation-damping system (a), with a slip liner (b), and with a cellular liner (c).
(Image & Quote Source: DiGiacomo et al. 2021)
Final Thoughts
The differences between helmet protection based upon the style or classification are fairly minimal. Do the smaller vents in mountain bike style helmets protect against sticks, rocks, and other debris in the event of falling, or crashing into them???
We can all agree that riding while wearing a helmet is safer. What type/style of helmet you wear is really more of a personal choice, even more so than what type of riding your doing. Do you value great ventilation, lightweight and compact, or does the larger mtb style helmet make you feel more secure? The only correct choice is what helmet you enjoy, regardless of what bike shops or your friends will tell you.
Jesse - Master of Science - Health & Human Performance - Bachelor of Science - Kinesiology: Jesse is the Director of Pedal Chile, which is a Bicycle Tour Company in the Chilean Patagonia. Jesse prefers to ride singletrack with a roadie helmet since it’s better ventilated and lighter.
Sources for this article:
Bland, M.L, “Assessing the Efficacy of Bicycle Helmets in Reducing Risk of Head Injury" (2019). Doctoral Dissertation
Bland, M.L., McNally, C., Zuby, D.S., Mueller, B.C. and Rowson, S. (2019). Development of the STAR Evaluation System for Assessing Bicycle Helmet Protective Performance. Annals of Biomedical Engineering, 48(1), pp.47–57.
Bland, M.L., McNally, C., Zuby, D.S. et al. Development of the STAR Evaluation System for Assessing Bicycle Helmet Protective Performance. Ann Biomed Eng 48, 47–57 (2020). https://doi.org/10.1007/s10439-019-02330-0
Bland, M.L., Zuby, D.S., Mueller, B.C. and Rowson, S. (2018). Differences in the protective capabilities of bicycle helmets in real-world and standard-specified impact scenarios. Traffic Injury Prevention, 19(sup1), pp.S158–S163.
Chow, T.K., Corbett, S.W. and Farstad, D.J. (1995). Do conventional bicycle helmets provide adequate protection in mountain biking? Wilderness & Environmental Medicine, 6(4), pp.385–390.
DiGiacomo, G., Tsai, S. & Bottlang, M. Impact Performance Comparison of Advanced Snow Sport Helmets with Dedicated Rotation-Damping Systems. Ann Biomed Eng (2021). https://doi.org/10.1007/s10439-021-02723-0
Hansen, Kirk, et al. “Angular Impact Mitigation System for Bicycle Helmets to Reduce Head Acceleration and Risk of Traumatic Brain Injury.” Accident Analysis & Prevention, vol. 59, Oct. 2013, pp. 109–117, 10.1016/j.aap.2013.05.019.
Mustafa, H., Pang, T.Y., Ellena, T. and Nasir, S.H. (2019). Impact attenuation of user-centred bicycle helmet design with different foam densities. Journal of Physics: Conference Series, 1150, p.012043.