If you choose to wear a bike helmet you’ll want to be sure it's in peak condition. We asked experts from Giro, Met and Bontrager when and why you should replace your lid.
“It really depends on how much care you take of the helmet,” says April Beard, Bontrager's product manager for helmets. “There is no evidence that the EPS liner will deteriorate from age, but there are things such as solvents, chemicals, environmental exposure, that can degrade the performance of the helmet.”
Helmets.org, a non-profit consumer-funded programme providing bicycle helmet information, largely backs up the manufacturer stance. They cite data from an MEA Forensic study in 2015 that found that the foam liners of used but not crashed helmets retained their performance over many years, with some the helmets tested being 26 years old.
The Snell Motorcycle Foundation has a slightly different stance, saying, “Glues, resins and other materials used in helmet production can affect liner materials. Hair oils, body fluids and cosmetics, as well as normal ‘wear and tear’ all contribute to helmet degradation.”
For these reasons, and the fact that noticeable improvements in the protective characteristic of helmets take place over time due to advances in materials, designs and production methods, Snell recommends a five-year helmet replacement period.
Ulysse Daessle of Italian brand Met says, “As we can’t follow the history and the usage of each helmet, we suggest that customers replace their helmet after three to five years of use. We arrived at this recommendation because the statistics of average use show that this is when a big percentage of helmets have been subject to hard conditions, crashes, marks of use…”
“That’s not to say the helmet will automatically be unsafe after five years, but as manufacturer we have to advise the customer: a helmet is a safety device and you really need to take care of it and change it in case of doubt. So we take this safety margin and advise you to change your helmet after five years of use.”
Giro’s advice is the same.
“We make a general recommendation that you replace your helmet every three to five years depending on use and handling,” says senior brand manager Eric Richter. “This is based on observation of the average user and factors like wear over time, weather, handling, the potential for degradation from personal care products like sunscreen or bug spray, and the simple fact that helmet technology does improve over time.”
You had a minor tumble off the bike, hitting your head but not very hard, or you accidentally dropped your helmet onto the road while carrying it; the helmet isn't broken and the shell looks fine, so surely it's okay to keep using it?
“It’s really hard to say,” says Met’s Ulysse Daessle. “It depends of many factors and we can’t say anything definitive as we are not inside the helmet! We advise in any case a really careful inspection in order to detect any cracks, bumps or scratches. If there’s any doubt, change the helmet.”
Giro’s Eric Richter says, “If you fall and the helmet is impacted, you should have it inspected or replaced immediately, even if no damage is visible. The reason is that helmet liners are made to absorb energy from impacts and they do this through their own degradation or destruction – like an airbag in a car. If the liner is compromised from an impact or other factors, it may not offer the full protective capability it was designed to provide.”
It's not just the EPS foam that can get damaged in a minor crash. You should also think about the integrity of the rest of the helmet – the straps and the fit system, for example, which are critical to securing the helmet properly on your head.
“Bear in mind that if the helmet did its job most people would tell you that they did not even hit their head, or did not hit their head that hard,” says Helmets.org.
You might have felt only a minor bump while the helmet received quite a serious blow. Most helmet manufacturers – Giro, Met and Bontrager included – offer crash replacement schemes where you can get a new helmet at a discount price after a nasty incident as long as it’s within a specified period after purchase, so it makes good sense to err on the side of caution here.
Regular inspection of your bike helmet for damage is sensible, but what exactly should you be looking out for?
“It’s easy to spot some signs telling you to replace your helmet,” says Ulysse Daessle of Met. “After a crash, damages like cracks to the EPS, bumps on the polycarbonate outer shell, wear and tears marks, could be visible.”
Giro’s Eric Richter says, “If a helmet is visibly damaged – a cracked outer shell, crushed or cracked foam liner or any other damage – don’t use it.
Any exposed EPS can start to look chipped or worn and if the polycarbonate shell shows a dent of any sort then you should replace the helmet. You might think that a small piece missing from the edge of the helmet isn’t important but there may be hidden damage to the construction.
Look inside the vents for any cracks or splitting of the EPS, and if the polycarbonate shell is separating from the EPS it's time for a new lid.
“It’s also important to understand than a helmet’s structure might be affected by heat, chemicals, stickers applied on the surface with unknown chemicals, or simply by cleaning the helmet with the wrong product [more on that in a mo],” says Ulysse Daessle. “Those are damages that are hard to spot and it’s up to the rider to be aware of this and take care of the helmet.”
Eric Richter says, “Remember that helmets don’t last forever and damage is not always visible. If at any time you are unsure about your helmet, or have questions about your helmet’s condition, we recommend that you visit your local retailer or contact the manufacturer before riding with it.”
The Helmets.org website also has a guide to inspecting your helmet, which is well worth a read if you're unsure.
The most important thing you can do to maximise the lifespan of your bike helmet is protect it from bumps and bangs wherever possible. If you take your bike in the car, for example, consider storing your helmet in a padded bag to keep it safe.
“Helmets are generally made of materials that can be damaged by many commonly-available cleaners,” says Giro’s Eric Richter. “Petroleum-based solvents or cleaners are especially dangerous. They can damage a helmet so that its protective capabilities are significantly reduced. Oftentimes this damage is not visible.
“For best results, clean the helmet using a soft cloth or sponge, warm water and mild soap (such as a mild dish soap). Allow the helmet to air dry and then store it in a cool, dry place where it won’t get damaged.”
Met’s Ulysse Daessle says, “As you put much love into taking care of your bike, it has to be the same for your helmet. Respect some basics: store it away from heat, sun and chemical products. Don’t do anything stupid with it like sitting on it or throwing it on the ground. Clean it with water and soap only, and don’t put any chemical, glue, paint or stickers on it as this might affect the characteristics of the shell.”
Eric Richter adds, “Treating the helmet with care and not exposing it to extreme temperatures will ensure the helmet lasts as long as possible.”
The boot of your car can get very hot in the summer, for example, as can a kitbag in direct sunlight.
You should replace the pads from time to time primarily for safety reasons – they help secure the helmet in the correct position on your head. There’s also comfort and hygiene to think about.
Beware of insect repellents too, in particular, those that contain DEET because, like some other chemicals, they can compromise the construction of the helmet as well as the appearance.
Quite a lot of modern helmets – particularly higher end ones – come with a MIPS (Multi-directional Impact Protection System) liner that’s designed to reduce the rotational forces that can result from certain impacts.
“The MIPS liner should not be removed or tampered with,” says April Beard of Bontrager. “You can wash it with a solution of mild soap and water, without removing it from the helmet. If any part of the MIPS system breaks you should replace the helmet.”