When To Replace It... is a new feature series in which we explore when one should replace common cycling products like helmets, apparel and various moving parts on your bike. Curious about a particular product? Shoot us an email at anne.rook@futurrnet.com
But what about wear from use and ageing of cycling soft goods? When should you change out other safety-critical items proactively, to ensure they will work as designed? There are no easy measuring guides or wear indicators for bike helmets like those on tyres, for instance.
Many helmet manufacturers and certification organisations generally recommend replacement on a calendar schedule, no matter the use or exposure. The independent U.S.-based publication Consumer Reports indicates that you should routinely replace your helmet every three to five years. Snell, the independent testing laboratory that certifies helmets, also suggests the same interval for replacing a bike helmet.
This guidance seems broad and potentially expensive, so we asked representatives from several helmet manufacturers to learn more about why and when to replace one of the most important pieces of cycling gear.
How and why bike helmets degrade
Helmets consist of several parts, each of which may wear at different rates, but they are only as good as the entirety of the helmet. Retention straps are exposed to the sun’s UV rays and sweat from riding in the heat.
The padded internal retention structure and fit adjustment system that contacts your head is protected from the sun, but is still exposed to sweat. The protective layer of a helmet, which may include proprietary systems like WaveCel, MIPS or Spherical, is shielded from UV, but may still be exposed to sweat and elements via cooling ports, and is susceptible to ageing from heat exposure.
And most obviously is a helmet’s external protective shell, which is always exposed to the sun and elements. Holding these components together is glue, which also ages at different rates depending on use and exposure.
It’s generally accepted that if you take a spill on your bike while wearing a helmet, and the helmet touches the ground, replace it. Doing so ensures you’ll be 100% protected should a helmeted head strike happen again.
But what if a helmet you've never crashed and looks to be in fine shape, even after a few years? Do you need to spend money on what looks to be a perfectly safe and functional bit of kit?
The authoritative U.S. Consumer Products Safety Commission (CPSC) indicates that, in the absence of brand-specific recommendations, a helmet is safe up to 10 years. But this guidance seems to be the outlier. Most brands of helmets advise a more frequent replacement plan: after five years at most.
Belgian helmet manufacturer Lazer, for example, indicates that "under normal use, it’s smart to start thinking about replacement after three years, and Lazer recommends definitely replacing helmets after five years."
Factors such as UV exposure, sweat, chemicals such as sunscreen and bug spray, all can prematurely age helmets. Lazer suggests that its helmets won’t "suddenly stop working after five years," but notes that "normal wear, exposure, and material ageing can reduce its effectiveness."
Follow the science and manufacturers’ claims about chemicals
Published research indicates age alone is not the sole factor for buying a new helmet. One study examined the EPS protective cores from 63 used and unused helmets, ranging in age between two and 20 years. It similarly found, "impact attenuation properties of EPS foam in field-used bicycle helmets do not degrade with [helmet] age." Another study concluded, "bicycle helmets do not lose their ability to attenuate impacts with age; however, other helmet features that may change with age were not evaluated."
So why throw away what looks to be a perfectly serviceable piece of protective gear?
Senior director of R&D at Giro, Steven Kennedy, says replace your helmet based on use, but do so within a 36 to 60-month range.
"Generally, we say three to five years as a range. That's because I think it's really based on how much the helmet's used," says Kennedy.
"I think the biggest, true degrader of material quality is UV exposure. So if you're using the helmet once a month through the summer in the northeast, and it's stored in a cool, dry basement for five years, that's one situation versus if you're using it in Arizona, year-round, every day as a commuter helmet, that's a completely different situation," cautions Kennedy.
"Ultimately, the UV rays, the dryness and drying out of glue is probably the biggest concern, from an engineering standpoint, over time," he says. "I think the best parallel is in Southern California, we all surf. Manufacturers say, don't put your wetsuit in the sun to dry. Everyone does, and you can see the glue turn yellow, crack and degrade."
"As they off-gas, they become a little more brittle. And so the biggest concern from my standpoint as an engineer is those glues drying out over three years of constant UV exposure, and that's where we would say replace the helmet and find something newer—fresh glue, everything's all together nice and tight," suggests Kennedy.
Joshua Rebol of Giant Bicycles told Cycling Weekly it tests helmets, "in lab conditions that would negatively affect impact performance like extreme heat, cold, wet and UV."
Giant cautioned riders to be mindful of where they store their helmets when not in use, and how to clean them.
"Longterm exposure to something like storage in a hot trunk of a car where temperatures easily hit 60º to 70ºC is something I don’t think riders are normally thinking about, and can prematurely age a helmet and cause a degradation of performance," says Rebol.
To prolong helmet life, he also suggests, "if your helmet comes with a soft cover or you can protect it with a soft case or bag, you should, by all means, use that for storage. Please don’t clean your helmet with solvents that could damage the shell or foams. Dish soap and warm water will do nicely."
Does your helmet pass the smell test?
Bug spray and spray-on are safe for teh skin but damaging to helmets
Giro’s Kennedy suggests riders practice good hygiene, and keep helmets smell-free. If there's a stank to your lid, it’s likely you’re cultivating bacteria, which is a skin irritant. Although this may not damage your helmet, it could damage your skin.
"Helmets are absorbing bacteria, and they can get pretty nasty, too. So, depending on how well you take care of your helmet, if you're sweating like crazy, you just throw it on the shelf at the end of the ride. There can be some pretty gnarly mould and bacteria growing on that stuff," says Kennedy.
And no one likes helmets with smelly bacteria farms.
"The stink is actually bacteria, and that's not stuff that you want to have on your skin. So similarly, depending on how well you take care of the helmet, is how long before it gets funky," he said.
"Then it can be a bad skin irritant on the sides of your face with straps, on the brow, that sort of thing. If you are super diligent, you rinse it with clean water after every ride—the brow pieces that you can take out—with a little antibacterial hand soap," observed Kennedy.
Bontrager’s Alex Applegate cautions against exposure to common protective and cleaning chemicals such as ammonia, which can negatively impact helmet function and lifespan. Since bug repellent is a commonly used product, keep it away from your headgear.
"We don’t have a full list [of chemicals or products] to share here; bug spray is often a large offender. We recommend applying bug repellent and [then] washing your hands before putting on your helmet; never spray on or near your helmet," says Applegate.
His colleague, Tim Kellagher, similarly cautions, "bug spray is something that is safe for skin, could be so damaging to foam and other materials."
And Kennedy, of Giro, also cautioned against getting spray-on sunscreen near your helmet, as it degrades the foam EPS protective component.
Bontrager, like Giant, suggests not storing helmets in hot automobiles at the risk of safety degradation.
Rudy Project suggests getting a new helmet after three to five years, too. The Italian manufacturer states that the protective layer of EPS foam degrades over time, and its protective properties become less than optimal.
This turnover cycle is also consistent with the advice offered by MIPS, the manufacturer of concussion-reducing technology licensed and utilised by many helmet makers: swap your lid when it’s between 36 and 60 months old.
Top takeaways for prolonging bike helmet lifespan
- Store in a cool, dry, dark location
- Do not use cleaning agents; use soap and water on helmets
- Keep bug spray and sunscreen away from helmets
- When locking your bike outdoors, take your helmet with you
- Examine straps and the retention system prior to each use for integrity
Replace your bike helmet if:
- You celebrate its fifth anniversary
- It hits the ground while being worn
- The outer protective shell is dinged and/or there’s a visible deformity on it
- Retention system no longer works like when it was new
- Excessive exposure to heat or UV