Overview

Most experienced EUC riders say that a full face helmet (that is, a helmet with a chin bar) is the way to go. However, there are multiple types of full face helmet to choose from, and different types are better suited to different types of riding and different riding speeds.

There are two main choices to make:

  1. Do you want a street or off-road helmet?
  2. What level of impact protection do you want? (Motorcycle helmets provide the highest level of protection.)

The table below shows the style of helmet corresponding to each combination of answers:

  Non-motorcycle Motorcycle
Street Downhill longboarding Standard “full face” motorcycle helmet
Off-road Mountain bike Motocross

Street helmets are probably better for cooler weather and higher speeds. As for protection, these are the minimum recommended levels of impact protection based on riding speed:

Helmet type Speed (mph) Certifications
Bicycle <20 CPSC, EN 1078
Downhill racing or e-bike 20-28 ASTM F1952, NTA 8776
Motorcycle >28 DOT, ECE, Snell

In terms of safety, the most important feature is helmet certification. The second most important feature is a technology like MIPS that reduces head rotation. (It can also help to get a brighter color for traffic visibility.)

Sellers of cheap helmets on sites like Amazon and AliExpress may lie about helmet certifications. See the show Fake Britain examine a fake bike helmet and a fake motorcycle helmet.

The specific type of motorcycle helmet I recommend for most riders is a dual-sport helmet with ECE certification. The reasoning behind these recommendations is explained further down.

Why a full face helmet?

Probably the most common type of EUC crash is a faceplant. This happens when, for any number of reasons, the wheel loses the ability to keep the rider upright, and the rider falls straight forward into the ground. The effect is similar to having a rug pulled out from under you.

A team of researchers at New Imperial College London simulated e-scooter falls showing how this happens.1 These falls are very similar to the EUC faceplant, and you can see some results below.

Faceplant simulation

In many cases riders will instinctively put their hands out to prevent hitting their face, but that doesn’t work every time and it’s not worth gambling your face on.

Street vs off-road

The face shields on street helmets keep bugs/dirt/tree pollen/dust/rain out of your face better than glasses or goggles can. At higher speeds even rain becomes surprisingly painful, so this is a big plus.

But the convenience comes with potential downsides, as the face shields also keep out wind and road noise. Generally, street helmets are less ventilated and quieter than off-road helmets, and off-road helmets can offer greater peripheral vision.

Ventilation: Due to the face shield blocking airflow, street helmets have less ventilation than off-road helmets. Off-road helmets’ pointy chinbars also provide more airflow to a rider’s face.

Noise: Street helmets are typically designed to be quieter, which is good at high speeds and around cars, but may be a nuisance at lower speeds and around relatively quiet bicycles and pedestrians.

Peripheral vision: Off-road helmets are made to fit goggles, and as a result they have larger eye openings that allow the wearer to see more than in traditional street helmets, at least when not wearing goggles. Off-road helmets also offer extra vertical (downward) vision, which can be useful for seeing the road near ahead or displays on the wheel. However, bicycle and motorcycle helmet standards all require a 210° horizontal field of view, so that, regardless of goggles, peripheral vision in certified helmets isn’t obstructed enough to cause a safety issue. In my opinion, the extra view is a comfort feature rather than a safety issue.

Dual-sport (aka adventure) helmets are a hybrid of both styles, with the larger eye openings to allow goggles as well as a face shield for the street. I think this is a sensible style of motorcycle helmet for most riders.

How much impact protection?

The US Consumer Product Safety Commission (CPSC) suggests that bicycle helmets can be appropriate for motorized scooters with speeds below 20mph (see footnote 4 of their helmet guide). There are many full face bicycle helmets, like the Demon Podium and the O’Neal Backflip, that fall into this category. So, for example, if you ride an InMotion V8, which has a top speed of 18mph, this kind of helmet is probably fine.

For protection at higher speeds, many riders opt for helmets certified for downhill mountain bike racing (ASTM F1952). Examples are the Fox Proframe and the TSG Pass. These helmets are subject to higher impact requirements for the more dangerous conditions of downhill racing. Since the downhill standard wasn’t intended for the street, it doesn’t specify a range of speeds, which has created some confusion. For example, the electric-scooter.guide website says these helmets are only intended for speeds <20mph, the same as regular bicycle helmets. Meanwhile Adam from Wrong Way suggests they’re appropriate up to 50-60kph (31-37mph).2

To clear up the confusion, I compare the downhill standard with two other standards intermediate between bikes and motorcycles: Snell’s L-98 standard for moped helmets and the Dutch NTA standard for e-bike helmets. The Snell L-98 standard is meant for vehicles traveling below highway speeds, while the NTA e-bike standard is meant for e-bikes traveling up to 28mph (the legal top speed for e-bikes in the Netherlands). Unfortunately, as of June 2023, no helmets have the moped certification, but at least we can use it for comparison. I currently know of three full face helmets with the e-bike certification, The Beam’s Virgo, Bell’s Full-10 Spherical, and Bluegrass’ Vanguard.

Many helmet standards, including these, use a common impact testing scheme, which involves dropping a dummy head in a helmet onto an anvil and measuring the acceleration of the head during the impact. If the acceleration exceeds a threshold, usually between 250 to 300 G’s, then the helmet fails the test. This video shows a helmet undergoing the certification tests:

The downhill racing, moped, and e-bike standards all have similar impact requirements. Snell’s moped standard seems to have the highest requirements, followed closely by the NTA e-bike standard, with ASTM’s downhill racing standard slightly below that. Following the NTA’s guidance, since the downhill certification’s requirements are slightly lower than e-bike requirements, downhill helmets would also be appropriate for speeds up to 28mph at the highest, and maybe a little less than that.

The table below shows the approximate drop heights (in meters) for each of these standards, along with bicycle and motorcycle standards for comparison:

Standard Flat Hemi Curbstone Max G
EN 1078 (Bicycle) 1.5 – 1.1 250
CPSC 1203 (Bicycle) 2.0 1.2 1.2 300
ASTM F1952 (Downhill racing) 2.0 1.6 1.6 300
NTA 8776 (E-bike) 2.2 ? 1.6 ?
Snell L-98 (Moped) 2.4 1.6 1.6 300
ECE 22.06 (Motorcycle) 3.4 – 2.9 275
DOT FMVSS 218 (Motorcycle) 1.8×2 1.4×2 – 400
Snell M2020R (Motorcycle) 3.4 3+2 – 275
Snell M2020D (Motorcycle) 3.1+2.6 3.1+2.6 – 275

Both the DOT and Snell standards require dropping the helmet twice on the same spot.

Are there downsides to all this impact protection? One potential downside is the extra weight it requires. But in practice, most people don’t seem to mind the weight and may not even notice it except on some long rides. Another claim, that the extra weight leads to neck injuries, is not supported by research.3

A more practical downside is that motorcycle helmets are optimized for motorcycles. In terms of hearing and ventilation, that means they’ll be a bit impractical at slower speeds.

Rotation (MIPS)

Research shows that brain injuries like concussion can be caused, not only by a direct impact, but also by sudden rotation. MIPS (Multi-directional Impact Protection System) is a technology widely available in bicycle helmets, meant to reduce sudden rotations in a crash. Research shows that MIPS, as well as some competing technologies, are successful.4

Most of this research is based on bicycle helmets, so it’s not clear to what extent it applies to motorcycle helmets. However, there are some motorcycle helmets with MIPS available. The new ECE 22.06 standard also includes a rotation test, which should address these concerns to some extent.

Motorcycle helmet certifications

The 3 most common motorcycle helmet certifications in the US are DOT, Snell, and ECE. Oddly enough, Snell and ECE certifications are incompatible with each other. Experts disagree about which is safest, though it looks to me like most support ECE over Snell. (Snell introduced a new M2020R standard for Europe that is compatible with ECE certification. I’m only discussing the original Snell standard here, which has become M2020D.)

DOT certification does not require independent testing. As a result, I would only trust DOT certification from established and respected brands.

The main disagreement is about how hard the helmet’s impact foam should be. Harder foam can absorb a harder impact, but provides less cushioning. Snell takes the position that the foam should be hardened in order to absorb the hardest impacts. The experts behind the ECE standard argue that harder foam doesn’t provide enough cushioning and causes too many injuries in smaller impacts, so ECE requires softer foam.

This disagreement is reflected in each standard’s test requirements. The table below shows that ECE has the lowest impact requirements, while Snell has the highest (the impact energy of two drops add together, so that, for example, DOT’s two drops are roughly like a single 3.6 meter drop). In contrast, ECE has the strictest head acceleration limits, while Snell is the most permissive. DOT is in between.

Standard Drop height, flat anvil (m) max G’s (official) max G’s in practice Head acceleration limiting factor
ECE 22.06 3.4 275 <2505 HIC
DOT FMVSS 218 1.8×2 400 around 2505 Dwell times
Snell M2020D 3.1+2.6 275 275 Peak acceleration

Two arguments lead me to prefer ECE. First, there’s reason to believe that a 1.8 meter test drop corresponds to the 90th percentile of motorcycle head impacts, and a 3 meter drop corresponds to the 99th percentile.6 The 3.4 meter drop required for ECE certification is already beyond the 99th percentile for motorcycles. Crash speed is correlated with injury severity,7 and, based on that, I think slower EUC speeds imply that the 99th percentile of EUC head impacts is significantly lower than that for motorcycles.

Second, I’m not aware of any case of an EUC rider suffering a brain injury due to inadequate motorcycle helmet foam, at least as of May 2023. This suggests to me that the extra hardness required by Snell isn’t needed for EUCs. In fact, I’m not aware of any rider even completely compressing the foam of a bicycle helmet. In the US, bicycle helmets are only tested with a 2 meter drop (for CPSC certification). So my guess is that the ECE impact requirement is adequate.

It’s not clear that these issues matter much. The difference is most pronounced for the rarer hard impacts that are near the limits of what the helmet foam can absorb, and is probably minor for the smaller head impacts that are much more common.

A few more notes:

The NHTSA independently tests a small subset of DOT-certified helmets every year. You can search the NHTSA’s helmet test results on their clunky website here. Unfortunately chin bars and face shields are not tested for DOT certification.

SHARP and CRASH are two more helmet testing organizations. Both use a 5-star rating system to evaluate helmets, which can be useful for getting additional info.

Eye protection

Having dust or bugs fly into your eye at 15mph is pretty uncomfortable, so I recommend wearing some kind of eye protection if your helmet doesn’t have a face shield.

If you normally wear glasses, they can do a decent job of keeping things out of your eyes. The downside, though, is that they can shatter in a crash. Shatterproof cycling glasses are a better solution.

ANSI Z87 certified motorcycle glasses or goggles provide an even higher level of protection.

More resources

  1. See Computational prediction of head-ground impact kinematics in e-scooter falls, or the press article summarizing the paper, E-scooter simulations highlight head injury risk to riders from falls. ↩

  2. In the video he only discusses helmets with a regular bicycle certification. I’m not sure why he ignores the official downhill certification. ↩

  3. For example, see Motorcycle helmets and cervical spine injuries: a 5-year experience at a Level 1 trauma center. ↩

  4. See “Impact Performance Comparison of Advanced Bicycle Helmets with Dedicated Rotation-Damping Systems” (link), “A New Assessment of Bicycle Helmets: The Brain Injury Mitigation Effects of New Technologies in Oblique Impacts” (link), “The Effect of MIPS, Headform Condition, and Impact Orientation on Headform Kinematics Across a Range of Impact Speeds During Oblique Bicycle Helmet Impacts” (link), and “Evaluation of two rotational helmet technologies to decrease peak rotational acceleration in cycling helmets” (link) ↩

  5. Officially DOT allows a maximum value of 400g, but in practice its dwell time requirements imply a maximum of around 250g. See Conflicts of Contemporary Motorcycle Helmet Standards, p. 168. ECE adds HIC (head injury criterion) requirements that also imply a lower G value. While I couldn’t find a rigorous estimate, we can infer something from Snell compatibility: many helmets have dual Snell and DOT certifications, but practically none are able to meet both Snell M2015/M2020D and ECE standards. This implies that ECE’s head acceleration limits are lower than DOT’s. (Snell M2020R adopts the same HIC limits as ECE.) ↩ ↩2

  6. For the 90th percentile estimate, see the Hurt report, p. 279. For the 99th percentile estimate, see Conflicts of Contemporary Motorcycle Helmet Standards, p. 165. ↩

  7. See the Hurt report, p. 213-215 ↩