No single answer covers every accessory. Four peer-reviewed impact studies on helmet add-ons found the outcome depends on where the accessory sits and how rigid the mount is, not on whether you added something at all. A soft, non-rigid mount placed away from the crown, front and side impact zones measured better outcomes in two studies. A rigid add-on at the wrong spot measured no real improvement in a third. Mount location is the variable that matters.
Your action camera sits two finger-widths from the crown of your helmet. That is the exact spot every major crash-test standard aims a drop rig at.
Nobody tested that combination before you bought it. The helmet was certified alone, as one sealed shell. The camera mount was never part of that test.
Four studies published between 2015 and 2024 finally asked whether that gap matters for riders who clip things onto a certified helmet. The answer is not yes or no. It is where.
Key takeaways
- A camera mounted on a cycling helmet cut peak head acceleration by about 51% at a 4 m/s impact and about 61% at a 6 m/s impact, compared with the same helmet bare (Butz et al., 2015).
- A rigid aftermarket shell add-on marketed as protective failed to significantly improve impact force at most tested locations on a football helmet (Breedlove et al., 2017).
- The newest add-on study found outcomes ranging from about 8% to nearly 63% lower modeled injury risk, and the only variable that explained the spread was which product and mount location were tested, not whether an add-on was present (Stark et al., 2024).
- ECE 22.06, the standard that governs most motorcycle helmets sold outside the US, certifies the complete unmodified helmet only. It has no test for rider-added accessories (UNECE).
The research behind this
Peer-reviewed impact tests this post is built on. Each card says what was measured, what was found, and what it cannot tell you.
Cycling helmet plus camera, impact testing
- What they measured
- A crash-test headform dropped at 4 m/s and 6 m/s onto a cycling helmet, with and without an externally mounted camera, recording peak head acceleration and skull force.
- What they found
- The camera mount reduced peak linear head acceleration by about 51% at 4 m/s and about 61% at 6 m/s versus no camera. Skull forces stayed well under the fracture threshold in both setups.
- What it can't tell you
- This is a cycling helmet, not a motorcycle shell, and a lab headform, not a live rider. One camera and mount geometry only.
Climbing helmet cameras, legislative impact criteria
- What they measured
- Three helmet types, three impact locations and five camera-mount combinations, tested against falling-object and fall-onto-surface scenarios.
- What they found
- Every helmet and camera combination tested complied with the relevant legislative performance criteria. No combination exceeded the published injury thresholds.
- What it can't tell you
- Built for a climbing-helmet standard and low-height falls, not the high-speed oblique impacts a motorcycle helmet standard tests for.
Aftermarket shell add-on drop testing
- What they measured
- Drop tests on football helmets fitted with a soft aftermarket shell-cover add-on, comparing impact force and head acceleration against the same helmets bare.
- What they found
- The add-on failed to significantly improve impact-force attenuation at most of the tested impact locations, despite being marketed as protective.
- What it can't tell you
- Football helmet geometry and impact profile differ sharply from a motorcycle full-face shell. One product line tested.
Shell add-on products, location and product dependence
- What they measured
- Pendulum impacts at the front, front-boss, rear and side of football helmets fitted with three commercial shell add-ons, single and paired.
- What they found
- Results varied by product and location. The best-performing add-on cut peak acceleration by about 7.9% and modeled injury risk by about 34% to 62.8%. The weakest add-on's gains were marginal.
- What it can't tell you
- Football, not motorcycle, and soft shell covers, not a chin-mounted filtration unit. No motorcycle-specific add-on data exists yet.
What the studies actually measured
None of these four studies tested a motorcycle helmet with an air-filtration unit clipped to it. That exact product does not exist in the published literature yet. What they tested is the closest available evidence: what happens, physically, when something is mounted onto a certified helmet shell.
Butz et al. (2015) dropped a crash-test headform fitted with a cycling helmet onto a rigid surface at 4 m/s and 6 m/s, once bare and once with an externally mounted action camera. They measured peak linear head acceleration and skull impact force at both speeds. The camera mount came out ahead at both speeds, not behind.
Martin et al. (2016) ran a larger matrix: three helmet categories, three impact points on each, and five different camera-mount combinations, tested against the specific drop heights and surfaces that climbing-helmet legislation requires. Every single combination passed.
Breedlove et al. (2017) took the opposite kind of product: a rigid, bonded shell cover sold to parents as added protection for football helmets. They dropped the same helmets with and without the cover, at several impact points, and measured the Gadd Severity Index and linear acceleration. At most points, the cover made no measurable difference.
Stark et al. (2024) is the newest and most detailed. Three different commercial add-ons, four impact locations, single add-ons and paired add-ons simulating a player-to-player collision. One product and location combination cut modeled injury risk by close to two thirds. Another barely moved the number. Same category of product, same test rig, very different results.
Read together, the four studies are not contradicting each other. They are measuring the same two variables from different angles: how rigid the mount is, and where on the helmet it sits.
From GoPros to comms units: a decade of riders adding things to certified helmets
Helmet-mounted action cameras went mainstream from around 2012. By 2015, the biomechanics community was publishing the first crash-test studies specifically because riders, regulators and the media were already asking whether the mounts were safe (Butz et al., 2015).
ECE 22.06, approved in 2020 and mandatory for new helmet type-approvals sold in most of Europe and Asia from January 2024, widened the set of impact points a helmet gets struck at during certification. The previous version, 22.05, used a smaller, fixed set of points. The new one uses a larger, partly randomised set. That tightening sharpens the question of what counts as the certified configuration. It does not loosen it.
Four independent studies, across four helmet categories, in nine years is still a thin body of research. It is also a growing one. This is an active, unresolved engineering question, not a settled debate on either side.
What actually breaks a helmet's certification, and what doesn't
A certified helmet is tested and approved as one complete, unmodified assembly, not a shell plus whatever you clip on afterward. The moment you drill into the shell or bond something to the EPS foam liner with a solvent-based adhesive, you have created a configuration nobody tested.
Neither ECE 22.06 nor the US FMVSS 218 covers rider-added accessories. Both certify the as-sold helmet only.
The research says the risk is not accessory versus no accessory. It is mount rigidity plus mount location plus added mass.
A soft, non-rigid mount placed at a non-critical zone measured better outcomes in two separate studies: the cycling camera mount (Butz et al., 2015) and the climbing camera mounts (Martin et al., 2016).
A rigid shell add-on marketed as protective failed to help at most locations in a third study (Breedlove et al., 2017). The newest study shows the effect is specific to a given product and location, so you cannot generalise from one accessory to another (Stark et al., 2024).
Before clipping anything to your helmet, check the mount touches nothing but soft fabric or foam, and that it sits off the crown, front and side of the shell. Those three zones are where every major standard aims its impact points.
| Impact speed | Reduction in peak acceleration |
|---|---|
| 4 m/s | 51% |
| 6 m/s | 61% |
More riders will be adding more things to their helmets by 2031
Comms units, action cameras, heads-up displays and now active filtration are all growing accessory categories on their own. At the same time, ECE 22.06's wider, partly randomised impact-point testing is the direction every major helmet market's standard is moving, not the exception.
If both trends hold, a materially higher share of helmets on the road will carry at least one rider-added accessory by 2031, while the certification standard itself keeps tightening around the bare shell. That widens the gap between what's certified and what's actually on a rider's head. It does not close it.
This is a projection built from the direction of two separate, sourced trends. It is not itself a measured study, and no source states it directly. The fix available to a buyer today is choosing an accessory engineered around that gap, not waiting for a standard that covers aftermarket add-ons. No major market has one yet.
What to do before you clip anything onto your helmet
- Check for drilling. If fitting it means drilling into the shell, the certified configuration is already gone.
- Check the adhesive. A solvent-based adhesive bonded to the EPS foam liner changes how that foam absorbs an impact. Clips, straps and magnets don't.
- Check the location. Keep the mount off the crown, front and side of the shell, the zones every major standard actually strikes.
- Check the release. A mount that stays rigid under load behaves differently from one that gives or detaches. Prefer the one that gives.
An EB helmet air-filtration unit is built around those four checks by design. It attaches with a magnet ring and a soft fabric and velcro seal at the chin underside.
Nothing bonds to the shell. Nothing sits at the crown, front or side. The H11 HEPA filter inside stops at least 95% of PM2.5, and the unit comes off without tools.
Frequently asked questions
Does mounting a camera void a motorcycle helmet's certification?
Not automatically. The four studies above found the outcome depends on mount rigidity and location, not on the presence of an accessory. Drilling the shell or bonding something to the EPS liner is what actually changes the tested configuration.
Is it safe to attach an air filter to a motorcycle helmet?
The literature on helmet add-ons, while not motorcycle-specific, consistently points to mount location and rigidity as the deciding factors. A non-invasive mount away from the crown, front and side impact zones is the lower-risk pattern across every study reviewed here.
Does ECE 22.06 test helmet accessories?
No. ECE 22.06 certifies the complete, unmodified helmet as sold. It has no provision for rider-added accessories, and neither does the US FMVSS 218.
Where is the safest place to mount something on a helmet?
Away from the crown, front and side, the three zones every major impact standard strikes during certification. The chin-bar underside, where a filtration unit's chin interface typically sits, falls outside those zones.
Sources
- Butz, R. M., Knowles, B. M., Newman, J. A., & Dennison, C. R. (2015). Snell certified bicycle helmets fitted with accessories: effect on dynamic impact performance. Journal of Biomechanics, 48(14), 3816 to 3824. doi.org/10.1016/j.jbiomech.2015.09.032
- Breedlove, K. M., Breedlove, E. L., Nauman, E. A., Bowman, T. G., & Lininger, M. R. (2017). The ability of an external shell add-on to decrease impact attenuation in high school football helmets. Journal of Athletic Training, 52(9). doi.org/10.4085/1062-6050-52.6.01
- Stark, R., Begonia, M., Jung, H., & Rowson, S. (2024). Effects of shell add-on products on football helmet impact performance. Annals of Biomedical Engineering, 52, 2923 to 2931. doi.org/10.1007/s10439-024-03627-5
- Martin, J. T., StClair, A., Willis, D., Rickman, K., & Hynd, D. (2016). Assessment of the effects of camera mounts on helmet performance. Injury Prevention, 22(4). doi.org/10.1136/injuryprev-2015-041857
- UNECE / WP.29. Regulation No. 22, revision 06 (ECE 22.06), motorcycle helmet homologation. unece.org/transport/vehicle-regulations
- NHTSA / US DOT. Federal Motor Vehicle Safety Standard No. 218, motorcycle helmets, 49 CFR §571.218. ecfr.gov, 49 CFR 571.218
Written by Ash, mechanical engineer and founder of Easi Breezi, building an active HEPA filtration system for motorcycle helmets (patent pending). Based between Hong Kong and Bali, riding daily in the traffic this blog writes about.